airplane following the implementation of subpart H would be subjected
to a more rigorous safety assessment.''
    Boeing asked whether an existing STC applicable to an existing
airplane model, applied to a new airplane of the same model but with
subpart H as part of its certification basis, would be subjected to
requirements of subpart H. It referred to the statement in the NPRM
that post-type certificate modifications have repeatedly introduced
wiring safety problems. Boeing asked for clarification of whether an
existing amended or supplemental type certificate would be subjected to
subpart H requirements prior to installation on an airplane with or
without subpart H as its basis of certification.
    In the case of a previously certified IFE system being considered
for installation on an airplane model with subpart H in its
certification basis, the answer is yes. The IFE system would have to be
certified to the EWIS requirements of subpart H. To do otherwise could
compromise the safety of the airplane by applying a lesser
certification standard to the IFE system. After the effective date of
the final rule, if a modification is proposed for an existing airplane
model without subpart H in its certification basis, whether or not the
modification will need to have subpart H in its certification basis
will be decided on a case-by-case basis, and the requirements of Sec.
21.101, Designation of applicable regulations, will apply.
7. Component Identification: EWIS (Sec.  25.1711)
    This rule requires applicants to identify EWIS components using
consistent methods that facilitate easy identification of the
component, its function, and its design limitations. For EWIS
associated with flight-essential functions, identification of the EWIS
separation requirement is also required.
    The number of this rule remains unchanged from its number as
proposed. In response to comment, we have revised wording to clarify
its intent, as discussed below.
    Boeing requested that we clarify Sec.  25.1711(a) by revising it as
follows:

    EWIS components must be labeled or otherwise identified using a
consistent method that facilitates identification of the wire EWIS
component, its function, and its design limitations, if any.

GE requested we revise the same paragraph to read as follows:

    EWIS components must be labeled or otherwise identified using a
consistent method that facilitates identification.

    Boeing and GE also requested that we remove the requirement in
Sec.  25.1711(b) that, for systems requiring redundancy, components
must be identified with component part number, function, and separation
requirement for bundles. They stated that all wiring should be treated
with the same level of care. The commenters contended that as the
proposed requirement was written, the regulation was impractical to
implement, since there are many redundancy separation categories in the
aircraft. A given bundle might have different separation requirements
from multiple other bundles, from hydraulic systems, and from air
ducts, and the requirement could vary with axial distance along the
fuselage. There would not be room to add all this data to the bundle
label.
    We have clarified Sec.  25.1711(a) as requested by Boeing. It is
the intent of this rule to require identification of all EWIS
components and not just the wire (which is one component of an EWIS).
We have revised that section by replacing the word ``wire'' with the
phrase ``EWIS component.''
    We have decided against deleting the phrase ``of the wire, its
function, and its design limitations, if any'' from Sec.  25.1711(a).
It is important that the EWIS component's function and design
limitation information be easily and readily available to maintainers
and future modifiers. Labeling components with this information will
help ensure that the level of safety provided by the original design is
not degraded. It will also prevent potential safety hazards from
improper maintenance and from replacement of original parts with parts
not designed or intended for that particular use.
    We have also decided against deleting Sec.  25.1711(b). We agree
that all wiring must be treated with care. But we are especially
concerned that wires and other EWIS components associated with flight-
essential or flight-critical systems be easily identifiable by those
designing and installing modifications, as well as by technicians
performing maintenance or repair. If a wire bundle has different
separation requirements as it is routed throughout the airplane, then
those varying separation requirements must be identified on the bundle
at the appropriate location where a particular separation requirement
is applicable. It would not be necessary to have each label on the
bundle contain all the differing separation requirements.
    IASA suggested that using a color-coding approach to identifying
critical systems would help post-TC modifiers easily identify critical
airplane systems. We agree with the need to help ensure easy
identification of these systems so that post-TC modifications and
repairs do not inadvertently introduce unintended failure modes.
However, the EWIS identification requirements of Sec.  25.1711 do not
prescribe the means by which EWIS is identified. It only requires that
the identification scheme be consistent throughout the airplane and
that modifications follow the same scheme. Color coding of EWIS may be
an acceptable means to comply with the requirements. We made no changes
because of this comment.
    US Airways stated that mandating identification for all terminals,
switches, connectors, or any component mounted in an area with limited
space could cause tags or something similar to be used. These would in
turn become contaminants.
    We agree that some EWIS components may be so small that it would be
impractical to label the component directly with textual data, and that
excessive use of tags could become a source of future contamination.
However, Sec.  25.1711 states that other means of identification can be
used if the component cannot be physically marked. For example, the
manufacturer's consistent marking scheme may be such that a color code
is used to mark these types of components. Applicants will have to
collaborate with their FAA Aircraft Certification Office to work out
the details. The method of identification is not mandated by the rule.
It is left up to the applicant to propose a method of identification.
We made no changes based on this comment.
8. Fire Protection: EWIS (Sec.  25.1713)
    This rule requires that EWIS components meet the applicable fire
and smoke protection requirements of Sec.  25.831(c). It further
requires that EWIS located in designated fire zones be fire resistant.
Insulation on electrical wires and cables is required to be self-
extinguishing when tested in accordance with the applicable portions of
Appendix F, part 1, of part 25. Section 25.1713 is adopted as proposed,
except that we removed the phrase ``at least'' that preceded ``fire
resistant.''
    EASA and Airbus commented that Sec.  25.1713(a) should also
reference Sec.  25.863. Airbus stated that this reference is common
practice for fire

protection compliance demonstration for EWIS components. EASA stated
that the equivalent EASA requirement, CS 25.1713, will reference CS
25.863.
    Because Sec.  25.1723 already requires EWIS components to meet
requirements of Sec.  25.863, it is not necessary to state the same
requirement in Sec.  25.1713.
    Boeing commented that proposed Sec.  25.1713(c) repeats and
replaces Sec.  25.869(a)(4), except with the change underlined below:

    (c) Insulation on electrical wire and electrical cable, and
materials used to provide additional protection for the wire and
cable, installed in any area * * *

Boeing requested that we change Sec.  25.1713(c) and/or Appendix F to
Part 25 to clarify which test article configurations (test components
individually or test components installed on the wire), and which
flammability tests are required for ``materials used to provide
additional protection for the wire and cable.''
    Boeing noted that Appendix F only refers to electrical conduit. It
said the rule is clear on how electrical conduit and insulation on wire
must be tested, but not on how to test the ``materials used to provide
additional protection for the wire and cable.''
    Boeing said that the rules should make clear what testing is
required for materials such as tight-fitting protective sleeve ( heat
shrinkable material, for example), loose-fitting protective sleeve
(such as spiral wrap or Varglas), or, for that matter, clamps, grommets
installed in holes, or other devices used to protect wire and cable.
    We have not revised Sec.  25.1713(c) and/or Appendix F because we
believe the requirements of Sec.  25.1713(c) are clear and unambiguous.
A material used to protect wire such as heat shrinkable material, or
loose fitting protective sleeving such as spiral wrap or Varglas, must
be tested in accordance with the requirements of part 25, Appendix F,
part I, in the same manner as electrical wire is tested. As stated in
Appendix F, Part 1(a)(v), it is not necessary to test small parts such
as clamps and grommets because they would not contribute significantly
to the propagation of a fire.
9. Electrical Bonding and Protection Against Static Electricity: EWIS
(Sec.  25.1715)
    Section 25.1715 requires that EWIS used for electrical bonding and
protection against static electricity meet the requirements of Sec.
25.899. It requires that EWIS components used for any electrical
bonding purposes (not just those used for protection against static
electricity) provide an adequate electrical return path under both
normal and fault conditions.
    Section 25.1715 was proposed as Sec.  25.1717. Its number was
changed to better harmonize with foreign airworthiness authorities. In
response to comments, we have revised the wording of Sec.  25.1715 and
expanded it to clarify meaning, as discussed below.
    Boeing stated that the term ``adequate electrical return path'' as
used in Sec.  25.1717 (now Sec.  25.1715) is difficult to define, and
should be replaced with performance criteria, such as the following:

    On airplanes having grounded electrical systems, electrical
bonding provided by EWIS components must provide an electrical
return path capable of carrying both normal and fault currents
without creating a shock hazard.

GE requested clarification of what constitutes a fault condition for
compliance with proposed Sec.  25.1717. It asked if a fault condition
includes failure of the bonding path, such as physical breakage.
    We have revised Sec.  25.1715 as requested by Boeing but have added
the phrase ``or damage to the EWIS components, other airplane system
components, or airplane structure.'' to the end of the suggested
revision.
    In response to GE's comment, the intent of the requirement is to
ensure that the current return paths are sized so they can accommodate
fault currents due to component failure. One example would be shorted
integrated drive generator power feeder cables where electrical bonding
is used for the fault current path.
10. Accessibility Provisions: EWIS (Sec.  25.1719)
    This rule requires access be provided to allow for inspection of
EWIS and replacement of their components, as necessary for continued
airworthiness.
    Section 25.1719 was proposed as Sec.  25.1725. Its number has been
changed to facilitate harmonization. No other changes have been made.
    EASA and Airbus commented that the wording of proposed Sec.
25.1725 (now Sec.  25.1719) is slightly different from that recommended
by ATSRAC. ATSRAC recommended that it state:

    Means must be provided to allow for inspection of EWIS and the
replacement of its components as necessary for continued
airworthiness.

The NPRM proposed Sec.  25.1725 to read as:

    Access must be provided to allow inspection and replacement of
any EWIS component as necessary for continued airworthiness.

    Airbus said that the word ``access'' is ambiguous. For example, it
said, it is almost impossible to access the inside of a conduit. U.S.
Airways noted that the rule needs to be revised because there are areas
where access to cables and wire runs is not possible.
    EASA suggested we change the rule to ATSRAC's original wording and
stated that it will use this wording in its equivalent requirement, CS
25.1719.
    We have decided to retain the wording of this requirement as
proposed. However, it should be noted that it is not the intent of the
rule to require human physical access in all cases. If such access is
not possible because of physical design, then other inspection
techniques could be allowed, such as use of a remote optical device.
However, in response to U.S. Airways' statement, Sec.  25.1719 does
require that access be provided to allow for inspection and replacement
for any EWIS component if it is necessary for continued airworthiness.
Therefore there will not be areas where EWIS components are
inaccessible for airplanes with Sec.  25.1719 in their type
certification basis.
    We have revised AC 25-1701-1 to reflect the fact that other types
of inspection techniques could be approved when human physical access
is not possible. Other types of emerging inspection techniques may not
require physical access.
11. Protection of EWIS (Sec.  25.1721)
    Section 25.1721 requires that cargo or baggage compartments not
contain any EWIS whose failure would adversely affect safe operation.
It also requires that all EWIS be protected from damage by movement of
people and from damage from items carried on the airplane by passengers
or cabin crew.
    Section 25.1721 was proposed as Sec.  25.1727. Its rule number was
changed to harmonize with regulations of foreign airworthiness
authorities. No other changes have been made.
    Boeing suggested that this rule be revised to state that EWIS
should be protected so it ``* * * cannot be damaged by normal movement
of cargo or baggage in the compartment.'' It said this change will
clarify requirements. Boeing, GE, and AIA/GAMA stated that maintenance
personnel need to be trained in proper EWIS handling.
    We have decided against revising Sec.  25.1721 in the manner Boeing
suggests. This requirement is not limited to ``normal movement.'' EWIS
in cargo or baggage compartments must be designed and installed so it
is protected in both normal and non-normal situations, such as when
cargo

containers come loose and strike compartment walls during flight
because of cargo system malfunctions.
    We agree that training personnel in proper handling of EWIS is also
necessary. Although we have not mandated this training, except for
technicians and inspectors working directly with EWIS, we have outlined
a training program for a wide variety of personnel who work on
airplanes. This training program is outlined in Advisory Circular 120-
YY, Aircraft Electrical Wiring Interconnection Systems Training
Program. We made no changes due to these comments.
    GE requested that the phrase ``risk of damage'' be deleted from
proposed Sec.  25.1727 (now Sec.  25.1721). It stated that risk of
damage implies control of the failure effect of damage that is assumed
to occur, as in Sec.  25.901(c). It said that because 14 CFR 25.1309
already adequately controls the relationship between probability of a
failure condition and its effect, risk of damage should be deleted from
proposed Sec.  25.1727.
    We believe it is necessary to address both damage and risk of
damage. Design and installation must be such that they preclude damage
to EWIS to the extent possible when all design and installation factors
are considered. We recognize, however, that it is not always possible
to prevent possible damage because of design or installation
considerations. EWIS components should be robust enough to minimize the
damage that could occur if they come into contact with cargo, baggage,
or personnel. We made no changes due to this comment.
12. Flammable Fluid Shutoff Means: EWIS (Sec.  25.1727)
    Section 25.1727 requires that EWIS associated with each flammable
fluid shutoff means and control be ``fireproof'' (as defined in Sec.
1.1) or located and protected so that any fire in a fire zone will not
affect operation of the flammable fluid shutoff means, in accordance
with Sec.  25.1189.
    Section 25.1727 was originally proposed as Sec.  25.1733. We have
changed its number to facilitate harmonization with foreign
airworthiness authorities. No other changes have been made.
    Boeing recommended that the word ``fireproof'' in Sec.  25.1733
(now Sec.  25.1727) be replaced with ``fire resistant'' to be
consistent with terminology used in Sec.  25.869(a) and proposed Sec.
25.1735 (now Sec.  25.1733). AIA/GAMA stated that fire resistant and
fireproof are not synonymous.
    AIA/GAMA is correct. ``Fireproof'' is a more stringent standard
than ``fire retardant.'' The basis for proposed Sec.  25.1727 is the
requirement of Sec.  25.1189(d) that ``each flammable fluid shutoff
means and control must be fireproof or must be located and protected so
that any fire in a fire zone will not affect its operation.''
    To ensure the effectiveness of flammable fluid shutoff means and
controls, the requirement for EWIS associated with those systems must
be as stringent as the requirement for other components of those
systems.
13. Powerplant and APU Fire Detection System: EWIS (Sec.  25.1731)
    This rule requires that EWIS that are part of a fire or overheat
detector system located in a fire zone be fire resistant, as defined in
Sec.  1.1. It also requires that EWIS components of any fire or
overheat detector system for any fire zone may not pass through another
fire zone unless:
     They are protected against the possibility of false
warning caused by fire in the zone through which they pass, or
     Each zone involved is simultaneously protected by the same
detector or extinguishing system.
    This rule also requires that EWIS that are part of a fire or
overheat detector system in a fire zone meet requirements of Sec.
25.1203. Section 25.1203 requires approved, quick acting, fire or
overheat detectors in each designated fire zone, and in the combustion,
turbine, and tailpipe sections of turbine engine installations, to
provide prompt indication of fire in those zones.
    Section 25.1731 was originally proposed as Sec.  25.1737. Its
number was changed for purposes of harmonization. No other changes have
been made.
    EASA requested that the reference to Sec.  25.1203 be moved to
Sec.  25.1719 (now Sec.  25.1705 Systems and Functions: EWIS).
    The intent of Sec.  25.1731 is to ensure that any EWIS components
associated with powerplant and auxiliary power units' fire detector
systems be as robust and fire resistant as the other components making
up these systems. The requirements of Sec.  25.1731 are based on those
contained in Sec.  25.1203. It could create confusion if the
requirements in Sec.  25.1731 were split between two separate subpart H
regulations as requested by EASA. Therefore we have retained the
originally proposed Sec.  25.1731 in this final rule.
14. Fire Detector Systems, General: EWIS (Sec.  25.1733)
    Section 25.1733 requires that EWIS associated with any installed
fire protection system be considered in showing compliance with the
applicable requirements for that particular system. This is a new
requirement that has not previously existed in part 25. Current part 25
regulations contain fire detection system requirements for powerplants,
lavatories, and cargo compartments. Each of these fire detection
systems requires electrical wire, and failure of this wire could lead
to inability of the detection system to function properly. This rule
applies to all required fire protection systems with the exception of
those for powerplants and APUs. Requirements for EWIS associated those
systems are contained in Sec.  25.1731.
    Section 25.1733 was originally proposed as Sec.  25.1735. Its
number was changed to better harmonize with foreign airworthiness
authorities. As stated previously in the discussion under the heading
of Systems and Functions: EWIS (Sec.  25.1705), we have revised this
rule to include references to Sec. Sec.  25.854 and 25.858, in response
to comments from EASA.
    Boeing and GE requested that proposed Sec.  25.1735 (now Sec.
25.1733) be removed from subpart H, because it is not directly related
to EWIS certification. The commenters noted that any system, not just
fire detection systems, which uses wiring in its design will be
required to meet requirements of subpart H.
    We have decided to adopt this requirement as proposed. Fire
detection systems need wire and other EWIS components to operate.
Failure of an associated EWIS component could lead to inability of the
detection system to function properly. Therefore EWIS components must
be considered an integral part of the fire detection system and meet
requirements of the applicable regulation.
15. Engine, Nacelle, and APU Wiring
    GE, Honeywell, and AIA/GAMA commented that engine, nacelle, and APU
wiring should be exempt from the proposed EWIS certification and
maintenance requirements. They said wiring in these areas is extremely
rugged, has excellent reliability in service, and is easily accessible
for inspection. They further stated that it is physically impossible
for a wiring failure or deterioration in the propulsion system to cause
a hazardous or catastrophic effect. They expressed the view that
existing regulations are

adequate, as demonstrated by service experience, and application of
these rules to engine, nacelle and APU wiring confers no safety benefit
and would result in significant cost to industry.
    We agree that EWIS components installed on the engine are very
robust. This is because the harsh environment in which they are
installed and the critical function engines play in the safe operation
of the airplane dictate such robust design and installation. However,
we do not agree that it is impossible for an engine wiring failure to
cause a hazardous or catastrophic condition. The following quote is
from the ``Lauda Air B767 Accident Report,'' dated July 21, 1993,
issued by the Aircraft Accident Investigation Committee Ministry of
Transport and Communications, Thailand--

    Investigation of the accident disclosed that certain ``hot-
short'' conditions involving the electrical system occurring during
an auto-restow command, could potentially cause the DCV to
momentarily move to the deploy position.

    This illustrates that, in the past, there have been designs where
an engine wiring failure could cause a catastrophic accident.
Application of these requirements to all wiring on part 25 airplanes
will help ensure that in the future we will minimize EWIS designs and
installations that could lead to serious safety issues. Our position is
consistent with ATSRAC's recommendation that engine wires not be
excluded from compliance with these new requirements. Additionally, our
regulatory analysis indicates that these rules are cost effective. We
made no rule change due to these comments.
16. Designated Fire Zones
    General Electric (GE) commented that the entire rulemaking package
was written from the perspective of wiring contained in the pressurized
fuselage, and then extrapolated to other areas. It stated as an example
the assumption made throughout the NPRM that an electrical fire is
catastrophic. GE stated that this is not the case in a designated fire
zone, because such zones contain specific design measures to safely
detect, contain, and put out a fire. The commenter stated that
unpressurized portions of the airplane spend much of the flight at
ambient pressures which will not easily support combustion. GE
suggested that itemizing fuel sources that are isolated from the
pressurized portion of the airplane--engine oil, engine fuel--as if
they coexisted with the heated and air-conditioned section of the
aircraft is very misleading.
    We believe that a fire in a fire zone is a safety issue. Fire zones
are designated as such because they are areas that have a higher
potential for a fire to occur. These zones do have fire detection and
suppression systems or other design features to mitigate effects of
fire. But these features are designed to meet a limited set of test
conditions for a limited duration of time and are not designed to meet
all anticipated sets of conditions that may exist in a fire zone. Any
fire on board an airplane, no matter where it occurs, has the potential
for serious safety consequences.
    The rule package was written with the objective of ensuring the
safety of wiring in the entire airplane, consistent with the intent of
ATSRAC.
17. Goal of the New Wiring Subpart
    GE and AIA/GAMA commented that many of the proposed subpart H EWIS
certification requirements are duplicative of existing part 25 rules.
They asserted that repeating a requirement in multiple locations
promotes differences in interpretation and confusion over acceptable
means of compliance. They recommended that the proposed subpart contain
new applicable requirements and act as a collector with references or
points to the existing applicable rules. They said this packaging
technique would provide the benefit of the common location sought by
the FAA to bring focus to the importance of EWIS design and
certification while minimizing the confusion, interpretation, and
divergence that challenges use of duplicate rule sets.
    We do not agree with the opinion that the proposed certification
requirements of subpart H are duplicates of existing part 25
requirements. To be a duplicate implies that the requirement exists in
both the new subpart H and in other places within part 25. This is not
the case. As described in the proposal's preamble, some of the subpart
H requirements previously resided in other part 25 subparts. But they
have been relocated to the new subpart H, and in some cases enhanced,
and no longer exist elsewhere in part 25. Also, many requirements of
subpart H are new requirements. In some cases (for instance in Sec.
25.1705 in this final rule), we reference existing part 25 requirements
that are applicable to EWIS but have not been moved into subpart H
because they do not lend themselves to division into wire and non-wire
portions. The goal of collecting existing part 25 wire-related
requirements and developing new requirements is to make them easy to
locate, ensure their application to EWIS, and highlight the importance
of considering wiring and its associated components as an airplane
system. Eliminating the majority of the proposed subpart H requirements
and simply referencing other wire-related requirements in a new Sec.
25.1700 series paragraph would not support this goal.
18. Harmonization
    British Airways, Royal Dutch Airlines (KLM), Airbus, and the
Association of Asia Pacific Airlines requested that the proposed FAA
and European Aviation Safety Agency's (EASA) EWIS requirements and
advisory material be fully harmonized and made identical where
possible.
    Harmonization of these requirements with EASA has been our goal
from the beginning. We have coordinated extensively with EASA and other
national civil aviation authorities to achieve this common objective.
While there may be some differences in wording because of our differing
regulatory procedures, our intent is to harmonize the substantive
requirements to the extent possible.

D. Instructions for Continued Airworthiness: EWIS (Sec.  25.1729 and
Appendix H)

1. Requirements for EWIS ICA
    Section 25.1729 requires that applicants prepare EWIS ICA in
accordance with requirements of Appendix H to part 25. Section 25.1729
was originally proposed as Sec.  25.1739. Its number has been changed
to facilitate harmonization with the regulations of foreign
airworthiness authorities. Otherwise, this rule remains unchanged from
the form in which it was proposed.
    This final rule also revises paragraph H25.4 and adds a new
paragraph H25.5 to Appendix H--Instructions for Continued
Airworthiness. Section H25.5 is a new requirement. It requires TC
applicants and applicants for design change to develop maintenance
information for EWIS as part of the ICA that are required for design
approval. The EWIS ICA must be developed through the use of an enhanced
zonal analysis procedure (EZAP). The ICA must include tasks, and
intervals for performing those tasks, to reduce the likelihood of
ignition sources and accumulation of combustible material and tasks to
clean the EWIS of combustible material if there is not an effective
task to reduce the likelihood of its accumulation. The ICA must also
include--
     Instructions for protections and cautions to prevent
accidental damage or contamination to EWIS during maintenance,
alteration, or repairs.
     Acceptable maintenance practices in a standard format.

     Wire separation requirements as determined under Sec.
25.1707.
     Information explaining the EWIS identification method and
requirements for identifying any changes to EWIS under Sec.  25.1711.
     Electrical load data and instructions for updating that
data.
    The ICA developed through the use of an EZAP must be in the form of
a document appropriate for the information to be provided, easily
recognizable as EWIS ICA, and either contain required EWIS ICA or
specifically reference other portions of the ICA that contain this
information.
    The amendment to section H25.4 requires that the Airworthiness
Limitations section of the ICA include any mandatory replacement times
for EWIS components.
    The final wording for the requirement for ICA as a single document
was revised from its proposed form, to clarify intent, as discussed
below. No other changes have been made to these rules.
2. ICA as a Single Document
    Boeing and AIA/GAMA requested we delete paragraph H25.5(b) of
Appendix H. This paragraph requires that EWIS ICA be contained in a
single document, easily recognizable as EWIS ICA. They said their
current approach is to produce several documents, including the
maintenance planning data document, airplane maintenance manual, and
standard wiring practices manual, with appropriate cross-references.
These documents may not be EWIS specific. Boeing and AIA/GAMA believe
separating EZAP-generated maintenance activities from those required by
Special Federal Aviation Regulation (SFAR) 88 defeats the intent of the
rule and is impractical.
    Additionally, Airbus, and GE suggested we revise H25.5(b) to say
``the ICA must be provided in a manner acceptable to the Administrator,
where instructions specific to EWIS are easily recognizable.'' They
believe there is no safety benefit in uniquely identifying ICA related
to, but not specific to, EWIS. They also requested that proposed Sec.
25.1739 (now Sec.  25.1729) be revised with a reference back to Sec.
25.1529 or deleted in its entirety. They stated that Sec.  25.1529
already requires Instructions for Continued Airworthiness to be
developed in accordance with Appendix H.
    We do not agree that paragraph H25.5 (b) should be deleted or
revised as requested. The requirements of paragraph (b) do not preclude
incorporation by reference of detailed information. However, we expect
the DAH to provide a document appropriate for the information provided,
in other words, a single or source document that either includes the
EZAP-generated EWIS ICA or specifies where those EWIS ICA can be
located. This also means that, if incorporation by reference is the
approach taken by the DAH, all referenced documents are available at
the same time as the EWIS ICA source document. We have revised the text
of final H25.5(b) to clarify that the requirement only applies to EWIS
ICA developed in accordance with requirements of H25.5(a)(1) and that
the ``document must either contain the required EWIS ICA or
specifically reference other portions of the ICA that contain this
information.'' This does not change the meaning of the requirement, but
clarifies it.
    We also do not agree with the request to delete or revise Sec.
25.1729. Having a separate requirement for EWIS ICA located within
subpart H is consistent with the purpose of creating the new subpart.
The goal was to collect existing part 25 wire-related requirements and
develop new requirements, make them easy to locate, ensure their
application to EWIS, and highlight the importance of considering wiring
and its associated component as an airplane system. We made no changes
due to this comment.
3. Standard Wiring Practices Manuals
    Airbus commented about the requirement to include acceptable
maintenance practices in a standard format. Airbus made the point that
electronic standard wiring practices manuals (SWPM), in which such
maintenance practices can be found, are easily searchable. It requested
that manufacturers who publish their SWPMs electronically be either
exempt from the requirement for a standard format for SWPMs, and/or an
interim master breakdown index (which was outlined in the AC as an
approach to standardizing SWPM formats without rewriting them), or able
to adopt a similar approach.
    We are rejecting Airbus's request to exempt electronic versions of
the SWPM from requirements of part 25, Appendix H, H25.5. The objective
of this requirement is to ensure that maintenance personnel can readily
access necessary information. They may work on many different models,
so having a standard format will facilitate this. An applicant may
propose an alternative ``standard'' format to that described in the AC,
as long as it achieves the same objective (again, taking into account
that maintenance personnel will be working on a range of models). The
master breakdown index described in AC 25-26 was developed so that
existing non-electronic SWPMs would not have to be reformatted. An
electronic SWPM, by definition, can be easily indexed to align with the
master breakdown index format as depicted in the AC. We made no changes
due to this comment.
4. Mandatory Replacement Times
    Airbus requested that the requirement in section H25.4 to include
mandatory replacement times for EWIS in Airworthiness Limitations of
ICA be deleted because it is not related to any requirements to define
mandatory EWIS replacement times.
    We are retaining H25.4. The intent of this requirement is not to
mandate life limits for EWIS components, but to ensure that the
designer consider whether EWIS life limitations are applicable to a
particular design and identify those limits in the Airworthiness
Limitations section of the ICA. Such limitations, if any, would be
identified when demonstrating compliance with Sec.  25.1703. That rule
requires that EWIS be installed according to limitations specified for
that EWIS component, and this might include life limits under certain
circumstances. For example, a given EWIS component may be well suited
for a particular environment, but because of technological limitations,
the material it is made of may degrade over time when exposed to
certain environmental stresses. The component manufacturer may
recommend that certain tests be performed at given intervals to ensure
that its material properties are still within its qualification limits,
and if they are not, recommend that the component be replaced. Life
limits might also be identified when demonstrating compliance with the
EWIS safety assessment requirements of Sec.  25.1705, as part of
identifying acceptable mitigation strategies to prevent hazardous or
catastrophic failures. We made no changes due to this comment.
5. Wire Identification Method Information
    Airbus, AIA/GAMA, and GE suggested we delete the requirement in
proposed H25.5 for information explaining wire identification methods
and requirements for identifying changes to EWIS. They stated that
changes to EWIS, including future identification, are the modifier's
responsibility, and a DAH cannot anticipate all possible future changes
and give instructions for identification methods for changed
components.

    This requirement is intended to ensure that EWIS components added
or changed due to post-TC modifications retain the same identification
scheme used by the design approval holder. It is not necessary for the
original DAH to anticipate future changes to EWIS. The original DAH is
only required to describe the original identification scheme used. An
example could be a particular color used to identify EWIS components
associated with a fly-by-wire system. It is the responsibility of the
future modifier to follow that EWIS identification scheme as required
by Sec.  25.1711.
6. Electrical Load Data
    GE requested confirmation that H25.5(a)(2), (3), (4), and (5) do
not apply to the existing fleet. Also, AIA/GAMA and GE contended that
electrical load data is a certification issue, not a continued
airworthiness issue, and future changes or updates to that information
is the modifier's responsibility. They requested that paragraph
H25.5(a)(5) be deleted.
    The requirements of H25.5(a)(2), (3), (4), and (5) do not apply to
the existing fleet unless a modification is introduced that would
require that these requirements be part of the type certification basis
of the modification, in accordance with 14 CFR 21.101.
    We agree that it is the responsibility of modifiers (e.g., STC
applicants) to ensure that they update the actual load data of the
airplane they are modifying and document the electrical load data as
required by H25.5(a)(5). However, we have decided against deleting
paragraph H25.5(a)(5). We are using this requirement as a means to
ensure that accurate electrical load data is available to those who
need it. Accurate electrical load data is necessary to help ensure
continued airworthiness. It is important that the load demand of an
airplane's systems not exceed the generation and distribution capacity
of its electrical power system. By ensuring this, the necessary levels
of electrical power will always be available for those airplane systems
needed for safe operation. We made no changes due to this comment.

E. Continued Airworthiness and Safety Improvements Subparts for
Operating Rules (Parts 91, 121, 125, 129)

1. Establishment of New Subparts
    This rule establishes new subparts in parts 91, 121, 125, and 129.
These new subparts will contain operator requirements for continued
airworthiness and safety improvements, just as the new part 26 will
contain requirements for continued airworthiness and safety
improvements applicable to DAHs. As we stated in the NPRM:

    The FAA believes that inclusion of certain rules under the new
subparts will improve the reader's ability to readily identify rules
pertinent to continued airworthiness. * * * The proposed new
subparts consist of relocated, revised, and new regulations
pertaining to continued airworthiness of the airplane. Unless we say
otherwise, our purpose in moving requirements to these new subparts
is to ensure easy visibility of those requirements applicable to the
continued airworthiness of the airplane. We do not intend to change
their legal effect in any other way. (70 FR 58537)

    Our creating these new subparts does not, by itself, impose any new
requirements; it simply establishes the locations in which these
requirements will be placed. In some cases, as with the fuel tank
safety provisions of today's final rule, we may adopt parallel sections
in all four new subparts. In other cases, as with the EWIS provisions
of today's final rule, we may adopt requirements in only certain
subparts. But in each case, the new requirements will only be adopted
after public notice and opportunity to comment where we will explain
the proposed scope and effect of the new requirements.
    Other new regulations and new subparts have been added to the CFR
since publication of the NPRM. As a result, some of the rule numbers
and some of the letter names for the new subparts that were proposed
for this rule have already been used. In this final rule we have
revised those rule numbers and subpart letter names where necessary.
    Provisions enabling each of the new Continued Airworthiness and
Safety Improvements subparts, which were inadvertently left out of the
proposal, have been added here. The placement of certain provisions
within the rules has also been revised. The table below indicates the
changes. Commenters' original references are retained here, however,
for ease of reference to the proposal, including references to draft
ACs.

       Table 3.--Operations Rules Changes From NPRM to Final Rule
------------------------------------------------------------------------
       Part                 Final rule                    NPRM
------------------------------------------------------------------------
91................  Sec.   91.1(d) (new).....  N/A.
91................  Subpart L--Continued       Subpart L--Continued
                     Airworthiness and Safety   Airworthiness and Safety
                     Improvements.              Improvements.
91................  Sec.   91.1501 Purpose     Sec.  Sec.   91.1501
                     and definition.            Purpose and definition.
91................  Sec.   91.1507 Fuel tank   Sec.   91.1507 Fuel tank
                     system inspection          system maintenance
                     program.                   program.
121...............  Sec.   121.1(g) (new)....  N/A.
121...............  Subpart AA--Continued      Subpart Y--Continued
                     Airworthiness and Safety   Airworthiness and Safety
                     Improvements.              Improvements.
121...............  Sec.   121.1101 Purpose    Sec.   121.901 Purpose
                     and definition.            and definition.
121...............  Sec.   121.1111            Sec.   121.911 Electrical
                     Electrical wiring          wiring interconnection
                     interconnection systems    systems (EWIS)
                     (EWIS) maintenance         maintenance program.
                     program..
121...............  Sec.   121.1113 Fuel tank  Sec.   121.913 Fuel tank
                     system maintenance         system maintenance
                     program.                   program.
125...............  Sec.   125.1(e) (new)....  N/A
125...............  Subpart M--Continued       Subpart M--Continued
                     Airworthiness and Safety   Airworthiness and Safety
                     Improvements.              Improvements.
125...............  Sec.   125.501 Purpose     Sec.   125.501 Purpose
                     and definition..           and definition.
125...............  Sec.   125.507 Fuel tank   Sec.   125.507 Fuel tank
                     system inspection          system inspection
                     program.                   program.
129...............  Subpart A--General.......  Subpart A--General.
129...............  Sec.   129.1(b)..........  Sec.   129.1(b).
129...............  Subpart B--Continued       Subpart B--Continued
                     Airworthiness and Safety   Airworthiness and Safety
                     Improvements.              Improvements.
129...............  Sec.   129.101 Purpose     Sec.   129.101 Purpose
                     and definition.            and definition.
129...............  Sec.   129.111 Electrical  Sec.   129.111 Electrical
                     wiring interconnection     wiring interconnection
                     systems (EWIS)             systems (EWIS)
                     maintenance program.       maintenance program.
129...............  Sec.   129.113 Fuel tank   Sec.   129.113 Fuel tank
                     system maintenance         system maintenance
                     program.                   program.
------------------------------------------------------------------------

2. Continued Airworthiness Subparts and Airworthiness Directives
    The Regional Airline Association (RAA) commented that proposed
Sec.  121.901(a) (now Sec.  121.1101(a)), as a stand-alone provision,
is unlimited in scope. It contended that the requirement can be
interpreted to mean that operators must incorporate any future design
and maintenance changes that a type certificate holder incorporates
into its ICA, regardless of their airworthiness status. The RAA said
that this would effectively eliminate the need for any future
airworthiness directives. The RAA said it therefore has the potential
to eliminate operator participation in the rulemaking process for
future original equipment manufacturers' recommendations affecting
maintenance and design of their fleet.
    In a similar vein, United Parcel Service (UPS) recommended we not
adopt the new subpart for part 121 and instead use the part 39 AD
process to implement required actions once the necessary data and
documents have been developed by manufacturers. It stated the new
subpart, as proposed, will allow the FAA to impose regulations prior to
development of a technically feasible solution available for comment.
UPS stated that operators would be unable to accurately comment on the
cost and feasibility of the actions required for compliance. The
current AD process allows operators the ability to comment on a
specific solution with a known cost impact.
    We do not believe that Sec.  121.1101(a) as a stand-alone provision
can be reasonably construed as unlimited in scope. Section 121.1101(a)
describes the purpose of the new Subpart AA and who it is applicable
to, and defines the ``FAA Oversight Office.'' It does not impose
technical requirements. Any specific requirements for continued
airworthiness and safety improvements will be proposed for comment in
the same way as the EWIS and fuel tank safety requirements included in
this final rule were proposed for comment. The FAA will continue to
issue airworthiness directives in accordance with requirements of 14
CFR part 39 when we find that an unsafe condition exists in a product
and the condition is likely to exist or develop in other products of
the same type design.
    We also disagree that subpart AA should not be created. The new
requirements contained in subpart AA are necessary to raise the level
of safety by correcting fleet-wide continued airworthiness issues.
Airworthiness directives only address specific unsafe conditions that
exist in a product and are likely to exist or develop on products of
the same type design. Continued airworthiness issues, such as EWIS
maintenance, affect all transport category airplanes. In addition,
using ADs to implement these requirements would mean that ADs would
need to be continually issued as new models, model variants, or
modifications are introduced by a DAH. The use of the AD process to
impose the requirements contained in subpart AA would not be the most
effective method to address these issues.
    We do not believe that adopting the new subpart instead of issuing
ADs will prevent operators from being able to accurately comment on the
cost and feasibility of the manufacturers' proposed requirements. It
would be impractical to set up a comment period for each specific set
of maintenance changes developed by the manufacturers, as the commenter
appears to want. However, a substantial cost/benefit analysis is always
prepared to support any proposed 14 CFR regulation and public comments
are solicited. This is a more comprehensive analysis than those
prepared for an AD. We made no changes due to this comment.
3. Type and Scope of Requirements
    The Air Transport Association (ATA) commented that in proposed
Sec.  121.1101(a), the words ``* * * may include, but are not limited
to * * *'' can be interpreted to mean that at a minimum the operator's
maintenance program must incorporate 100% of all design changes and
100% of all ICA, not just the EWIS/FTS design changes and ICAs to be
developed. ATA stated there is no justification presented in the NPRM
for such an open-ended regulatory requirement. It said this requirement
cannot be interpreted consistently by all operators impacted or by all
the FAA Aviation Safety Inspectors with oversight responsibility. ATA
recommended that the second sentence of Sec.  121.1101(a) be rewritten
as follows:

    These requirements may include revising the maintenance program
by incorporating the intent of applicable revisions to the
Instructions for Continued Airworthiness, as identified in this
subpart.

    As explained in the NPRM (at 58538-9), this rulemaking is one of
several to adopt new requirements relating to continued airworthiness,
and the purpose of creating these new subparts is to have a common
location for all of these requirements, both existing and proposed. The
purpose of Sec.  121.1101(a) (and its counterparts, Sec. Sec.
91.1501(a), 125.501(a), and 129.101(a)), is to identify the type and
scope of requirements that may be included within this subpart. It is
purposely broad to encompass possible future rulemaking but does not
itself impose requirements. Any future requirements will be proposed
through the normal rulemaking process and all interested parties will
be afforded the opportunity to comment on them.
    As under current requirements for ICA, a TC holder is required to
update ICA to address any new design change for which they get
approval. An operator altering an airplane to incorporate the new
design change would have to update its maintenance program ``based on''
the approved ICA. TC holders may also update their ICA in the absence
of design changes, but, as under existing regulations, these updates
would not be mandatory unless we issue an AD mandating them, which we
would do only if necessary to address an unsafe condition. Operators
may also independently revise their EWIS and fuel tank ICA. Under
today's final rule, these changes would have to be approved by their
Principal Inspector.

F. Operating Requirements for EWIS (Parts 121 and 129)

1. Requirements for Maintenance and Inspection Program Revisions
    For those operating under parts 121 and 129, we are establishing,
within the new Continued Airworthiness and Safety Improvements
subparts, requirements to revise maintenance and inspection programs to
include maintenance and inspection tasks for EWIS. The tasks must be
based on ICA developed in accordance with Appendix H.
    We have extended the compliance dates for Sec. Sec.  121.1111 and
129.111. They were originally proposed with a compliance date of
December 16, 2008. But as a result of comments discussed earlier we
have decided to fix the time for compliance as a number of months after
the effective date, rather than as a hard date, and to also allow some
additional time beyond that which was originally contemplated. The
compliance date for these rules is now 39 months after the effective
date of the rule. We have also revised these rules to clarify meaning,
as discussed below.
2. ICA Developed by Design Approval Holders
    Boeing noted that the proposed operational regulations would
require that the maintenance program revisions be based on ICA
developed by the DAH.

Boeing would like clarification of the interpretation of the term
``based on.'' It asked whether certificate holders are expected to
adopt, without change, the ICA provided by the DAHs.
    As discussed previously, it was not our intent to require operators
to use ICA developed by TC holders. While we think it is very likely
that operators will use those ICA, we intend that they be able either
to develop their own or to contract with third parties for ICA, as long
as they meet the applicable requirements. We have revised the
operational rules to clarify this flexibility. Deviations from the EWIS
or fuel tank system maintenance programs that have been developed in
accordance with the requirements of SFAR 88 or Appendix H must be
approved by the operator's Principal Inspector, who will coordinate the
changes with the FAA Oversight Office as appropriate. Similarly, later
changes to either the EWIS maintenance program or the fuel tank system
maintenance program must be approved by the operator's Principal
Inspector, who will coordinate the changes with the FAA Oversight
Office, as appropriate. In some cases, coordination with the Oversight
Office will be necessary to ensure that the program's original
objectives are still met. Details of these coordination procedures are
defined in an FAA order and described in an advisory circular.
3. Different Requirements for Existing and Future Designs
    RAA requested that proposed Sec.  121.911 (now Sec.  121.1111) be
revised so the performance objective of the ``retrofit'' requirements
may be distinguished from the design changes that may be considered for
newly manufactured fleet types. The commenter assumed that each OEM
will be required to re-certify to the new standards provided in the
part 25 proposal, and that carriers would be subjected to a massive
retrofit program. NACA requested that we clarify requirements by being
more specific about differences between new production aircraft and
retrofitting aircraft. They ask if all the part 25 enhancements will
become ICA and fall under these requirements.
    At the outset, Sec.  121.1111 requires neither ``retrofit'' nor
``design changes.'' It simply imposes requirements for operators'
maintenance programs. We agree that some clarification is appropriate.
As explained in the NPRM, the purpose of Sec.  26.11 is to require type
certificate holders to develop ICA for existing airplanes that would
enable operators to comply with this section. For those airplanes, only
certain provisions of new paragraph H25.5 (H25.5(a)(1) and (b)) are
required. But for all future airplane designs subject to new Sec.
25.1729, type certificate applicants must show compliance with all
provisions of paragraphs H25.4(a)(3) and H25.5. Our intent in the
operational rules is to require operators to incorporate into their
maintenance programs all of the EWIS ICA developed for each of their
airplanes. For existing airplanes, this would be limited to ICA meeting
paragraphs H25.5(a)(1) and (b). For future airplanes, this would also
include ICA meeting the remaining requirements of paragraphs
H25.4(a)(3) and H25.5. We have revised Sec.  121.1111 (and Sec.
129.111) to clarify these differences.
    KLM disagreed with the requirement for operators of all airplanes,
regardless of the airplane's age, to implement maintenance program
inspections and procedures for EWIS. The commenter contended that the
amount of exposure to deteriorating factors on new aircraft is limited,
so there is negligible benefit to performing additional maintenance
tasks on wiring. The commenter also pointed out that checking wiring on
a new aircraft may even cause more wiring failures due to maintenance
near the wiring. KLM suggested we consider a threshold for starting the
first inspections.
    Although older airplanes have been exposed to more stressors that
can accelerate the degradation of wire and other EWIS components, age
is not the sole factor in degradation. We do not want to specify a
threshold for starting the first EWIS inspections. The intervals for
performing the inspections, including the first ones, are determined by
performing the EZAP analysis. Factors to be considered in establishing
intervals are the hostility of the environment in which the EWIS is
located and the likelihood of accidental damage. Neither of these
factors is necessarily dependent on age, and EWIS failures can occur on
newer airplanes. So the ``threshold'' for the first EWIS inspection
would normally be the same as the interval, measured from the issuance
of the first certificate of airworthiness. The results of the analysis
are reviewed by industry working groups (as part of the MSG-3 process)
and approved by the FAA Oversight Office. It is during the industry
working group review that the final inspection intervals are set and
subsequently approved by the FAA. We made no changes due to this
comment.
4. ICA for Alterations
    British Airways requested that proposed Sec.  121.911 (now Sec.
121.1111) be revised to state that if changes to the ICA are required
after alterations, incorporation of these changes into the maintenance
program may be delayed until after the airplane has resumed service,
but before it reaches the ``relevant age or flight hours.'' The
commenter expressed concern that the current wording would result in
extended operational delays and grounded aircraft after minor
alterations or repairs. British Airways also expressed concerns about
SFAR 88-related alterations/component changes conducted while the
airplane is in a normal operating environment (e.g., at the ramp). It
asked whether inspections or incorporation of ICA changes to the
maintenance program must be completed before resuming operations and,
if so, requests a rule change allowing ICA incorporation into
maintenance programs after the airplane returns to service but before
it reaches the ``relevant age or flight hours.''
    The only alterations for which EWIS ICA will be developed are those
for which compliance with either Sec. Sec.  26.11 or 25.1729 must be
shown--in other words, major alterations approved under STCs or amended
TCs. The only alterations for which fuel tank system ICA will be
developed are those for which compliance with either SFAR 88 or Sec.
25.1529 must be shown--again, major alterations approved under STCs or
amended TCs. We believe that any of these alterations would be
scheduled to occur during a period of allocated downtime such as a
scheduled maintenance ``C Check.'' The maintenance planning for such
modifications should include the actions necessary to incorporate
additional EWIS or fuel tank ICA into the approved maintenance or
inspection program. No additional time would be needed for these
actions. Accordingly, no changes were made due to these comments.
5. Alaska Operations
    Senator Stevens of Alaska stated that this rule will have severe
consequences to residents and cargo carriers operating in his state.
Referencing Section 1205 of the Federal Aviation Reauthorization Act of
1996 (49 U.S.C. 40113(f)), and the uniqueness of aviation in Alaska,
Senator Stevens, Everts Air Cargo, and Alaska Senator Murkowski
requested that ``intrastate'' operations in Alaska be exempted from
this rule.
    Consistent with 49 U.S.C. 40113(f), the FAA has carefully
considered the potential impact of this rulemaking on Alaska intrastate
operators to determine whether intrastate service in Alaska would be
adversely affected. We have

determined that there would not be an adverse effect and that
regulatory distinctions are inappropriate.
    Under both EAPAS and the Fuel Tank Safety Rule, manufacturers are
required to develop maintenance program revisions and make them
available to operators to support their compliance with the operational
rules. We have concluded that in the case of both the EAPAS and FTS
operations rules, any burden on affected operators in implementing
these changes would not have a significant impact. Under EAPAS, the
changes would be integrated into existing inspections that are
currently performed during heavy maintenance checks. The fuel tank
tasks, which would be aligned with the EAPAS inspections, would also be
performed during these checks. Because these additional inspections
would be only a small additional piece of a much more extensive
maintenance visit, we concluded that they would have no adverse effect
on intrastate service in Alaska.
    Lynden Air Cargo requested that the L-382G aircraft be excluded
from requirements of proposed Sec. Sec.  121.911 and 121.913 (now
Sec. Sec.  121.1111 and 121.1113). Senator Stevens asked that Lynden
Air Cargo's six L-382G airplanes in interstate operation be exempted.
Lynden Air Cargo said that it does not carry passengers and operates a
small fleet largely outside the U.S. It stated that it is in the public
interest to maintain its unique capabilities in Alaska where it
supports remote communities and projects with no roads or waterways, as
well as regularly supporting the U.S. military during critical
campaigns and the ongoing war on terrorism. Lynden Air Cargo also asked
to be excluded from Sec.  121.909 (now Sec.  121.1109).
    We do not believe it is appropriate to exclude the L-382G from
requirements of Sec. Sec.  121.1111 and 121.1113 for those airplanes in
interstate operation. The safety rationale for these rules applies
equally to that airplane. Lynden Air Cargo may apply for an exemption
to these rules in accordance with 14 CFR part 11. However, under Sec.
11.81, Lynden Air Cargo must provide information stating why granting
such an exemption would be in the public interest and why it would not
adversely affect safety, or how it would provide a level of safety
equivalent to the final rule. Also, we are not granting Lynden Air
Cargo's request for an exclusion from Sec.  121.1109. That requirement,
which is not a new rule but simply a renumbering of the requirement
formerly designated as Sec.  121.370a, has been in effect since
November 1, 2002 (reference 67 FR 72761, December 6, 2002), and we did
not make any changes to that rule other than changing its section
number.
6. EWIS Inspections
    Lynden Air Cargo stated that it does not have the engineering staff
to effectively analyze and comment on the myriad complexities
associated with the proposed certification rule changes. However, it
said that with an aircraft type certificated under CAR 4b (Lockheed L-
382G Hercules), the cost to ``retroactively'' apply these new
certification rules would require extraordinary expenditures. Lynden
had the following concerns about the practical application and
implementation of specific inspection criteria for EWIS under EZAP-
developed methods:
     How does an inspector accomplishing a general visual
inspection (GVI) or a detailed inspection (DET) of EWIS make a specific
determination of airworthiness? The FAA has failed to state an
objective criteria in its proposed rule (i.e., what will be the accept/
reject criteria?).
     If there are no actual circuit defects, what corrective
action will be required? An immediate action? Or can it be scheduled
and effectively planned for a future inspection action?
     Disturbing wire bundles for inspections can induce more
problems than are corrected.
    The proposed operating rules do not require ``retroactive''
application of design requirements. They do require that operators
include EWIS maintenance tasks in their maintenance programs. Any post-
inspection actions are based on results of the GVI or DET. If
inspections determine that EWIS components need cleaning or repairing,
procedures for accomplishing these tasks are contained in the airplane
manufacturer's standard wiring practices manual or equivalent
procedures developed by the operator. If inspection shows that no
circuit defects exist (to use the words of the commenter) then no
corrective action would be required. We agree that moving, or
disturbing, wire bundles does have the potential to cause damage if not
done with care. Precautions for preventing such damage should be part
of the operator's overall EWIS maintenance program.
7. Non-U.S. Registered Airplanes
    Boeing requested that the FAA clarify whether the proposed part 129
rule would affect foreign operators operating non-U.S. registered
airplanes into the United States. They noted that part 129 usually
applies to these operations and it seems unusual that they have been
omitted in the proposed rule.
    Under International Civil Aviation Organization (ICAO) Annex \7\ 8,
the state of registry of an airplane is the state responsible for its
airworthiness. For this reason, the airworthiness regulations of part
129, including those contained in new subpart B, apply only to U.S.-
registered airplanes.
---------------------------------------------------------------------------

    \7\ ICAO's 98 articles, created and accepted at its Chicago
Convention, established the privileges and obligations of member
states. Standards and recommended practices of ICAO are designated
as ``Annexes'' to the Convention.
---------------------------------------------------------------------------

8. Taking Airplanes Out of Service
    US Airways requested clarification of Sec.  91.911 to stipulate
that aircraft need not be taken out of service specifically to
accomplish the revised inspections.
    We believe that U.S. Airways meant to ask for clarification of
Sec.  121.911 (now Sec.  121.1111) instead of Sec.  91.911, which is
not contained in the proposal. Operators will have considerable
flexibility in determining when inspections will be performed. For
example, in the appendix of the DAH EZAP AC, which describes an
acceptable procedure for establishing EWIS inspection intervals, even
inspections of EWIS located in the most severe environment with the
highest risk of accidental damage may be performed at intervals ranging
from an ``A'' check to a ``1-C'' check, which are normally scheduled
maintenance intervals. Although we cannot guarantee that an airplane
will not have to be taken out of service specifically to accomplish the
new EWIS maintenance program requirements, we believe these tasks can
be scheduled to be performed during other scheduled maintenance times.
Section 121.1111 does not require tasks to be accomplished at any
particular intervals. It only requires that the maintenance program for
a particular airplane include inspections and procedures for EWIS.
9. Training
    The NTSB referred to its recommendation A-00-108 of Sept. 19, 2000,
in which it asked the FAA to address the need for improved training of
maintenance personnel to ensure adequate recognition and repair of
potentially unsafe wiring conditions. The NTSB commented that, since
non-EWIS maintenance actions often compromise EWIS safety, training of
all maintenance personnel on EWIS maintenance and inspection is
critical. The board would like us to amend the NPRM to specifically
state that all maintenance personnel must receive EWIS training.

    We agree with the NTSB on the importance of training personnel not
directly involved with EWIS maintenance and inspection. But the cost of
training all groups identified by ATSRAC as people working directly
with, indirectly with, or in the vicinity of, EWIS was not commensurate
with the benefits. While not required as a result of this final rule,
AC 120-94 provides a sample curriculum for a more comprehensive
training program. We strongly encourage organizations to voluntarily
offer this training.
10. Reporting Requirements
    The NTSB commented that in its recommendation A-00-108 it asked the
FAA to address improved reporting of potentially unsafe electrical
wiring conditions. It noted that the NPRM holds manufacturers and
operators responsible for proper maintenance and inspection of EWIS.
The board contends there can be no quantitative measurement of how well
the maintenance and inspection system is performing without an
effective mechanism to collect basic data, examine the findings, and
provide reporting about performance.
    The NTSB noted that, even though it has supported the FAA's
previous NPRMs to revise and improve the service difficulty reporting
(SDR) system, the FAA has withdrawn both. It noted that restricted
access to existing data and inability to effectively search available
data inhibits research into recurring or potential problems that may
exist across operators, and such research is important in the
prevention of accidents. The board strongly encouraged the FAA to amend
the NPRM to address this issue and revise the SDR system, regardless of
any potential industry opposition.
    We have developed an Enhanced Airworthiness Datamart (EADM),
covering the years 1995 to the present, which provides analysts with a
more detailed view of SDRs. We have deployed the EADM on the Aviation
Safety Information Analysis and Sharing (ASIAS) system secured portal.
It integrates those reports with information on aircraft age, hours,
and cycles from the Airclaims database. The resulting data set allows
the user to identify trends in service difficulties as a fleet of
aircraft ages.
    Also, with the 1995 creation of the Air Transport Association (ATA)
code 97 for electrical wiring, precise reporting of electrical problems
is possible. In 1995 the FAA updated its Joint Aircraft Systems/
Component Codes (JASC) to include electrical wiring. We added ATA code
97 to each airplane system category for the wiring within those
systems. Because of these new analysis tools, we made no changes due to
this comment. While the value of the contents of service difficulty
reporting systems is contingent upon the accuracy of reporting by the
operators, the data is publicly available and useful in analysis
(http://av-info.faa.gov/isdr/SDRQueryControl.ASP?vB=IE&cD=32).

G. Operating Requirements for Fuel Tank Systems (Parts 91, 121, 125,
and 129)

1. Requirements for Maintenance and Inspection Program Revisions
    This rule includes provisions for operators to revise their
maintenance programs by adding maintenance tasks for fuel tanks. These
maintenance tasks must be based on ICA that have been developed in
accordance with SFAR 88 or Sec.  25.1529 and Appendix H and approved by
the FAA Oversight Office. Parts 91, 121, 125, and 129 each contain
these requirements in the new subparts for Continued Airworthiness and
Safety Improvements. These fuel tank requirements are not new
requirements. Rather, they clarify requirements of previously existing
rules.
    When this rule was proposed in October 2005, our intent was to set
the same operator compliance date for the fuel tank and EWIS
maintenance program revisions. This would have allowed both sets of
tasks to be added at the same time and required that the maintenance
program be revised only once. As discussed earlier, the rulemaking
process took longer than expected. At this time, we do not want to
delay inclusion of the fuel tank tasks into maintenance. Thus, while
the compliance date for the EWIS maintenance revision requirements of
Sec. Sec.  121.1111 and 129.111 has been changed, the compliance date
for this fuel tank maintenance revision requirement remains December
16, 2008, the date that was originally proposed. We have, however,
changed the date by which the certificate holder must submit
maintenance instructions for auxiliary fuel tanks to the FAA Oversight
Office. That date is now June 16, 2008. The list of airplanes excluded
from the requirements of these rules has also been changed. The
requirement in Sec.  26.11 that the EWIS ICA prepared by the DAH must
be compared with fuel tank ICA to ensure compatibility and minimize
redundancy remains unchanged.
2. Airplanes Excluded From Fuel Tank System Operating Requirements
    We have revised the list of airplanes excluded from the operating
requirements for fuel tank systems. For these rules, which affect
airplanes operating under parts 91, 121, 125, and 129, the list of
excluded airplanes includes those models of airplanes that are neither
U.S.-registered nor operated under these parts. Because of this, the
type certificate holders have not complied with SFAR 88 and, in several
cases, the type certificates have been surrendered. Subjecting these
models to the operational requirements for fuel tank safety would,
therefore, have no effect.
    Additionally, since the Vickers Viscount airplane was originally
type certificated before January 1, 1958, this airplane is not subject
to the EAPAS or Fuel Tank Safety rules because of the general exclusion
of airplanes type certificated before that date. This airplane model
has been removed from the exclusion list originally proposed.
Similarly, the Convair and DC-3 models that have been modified to
incorporate turbine-powered engines are also covered by this general
exclusion. The Lockheed L-300 has been added to the exclusion list.
That exception was granted because there is only one qualified
aircraft, which was modified, used, and later retired by NASA in 1995.
It would not be cost effective to bring it into 121 operations.
    The proposal excluded the Lockheed L-188, the Mitsubishi YS-11, and
the BAC 1-11. There are still more than 20 airplanes of each model
listed on the U.S. registry. For these models, the FAA has granted
partial exemptions to the respective DAHs for SFAR 88 requirements. In
each case, these exemptions, while relieving design approval holders of
some requirements, also have required them to develop service
information to be provided to affected operators and have explicitly
declined to exempt the operators from these operational rules.
Therefore, we have reconsidered the proposed exclusion of these models
and concluded that they should not be excluded.
    The following airplane models are excluded from the Fuel Tank
Safety Operational Rules:

(1) Bombardier CL-44
(2) Concorde
(3) deHavilland D.H. 106 Comet 4C
(4) VFW-Vereinigte Flugtechnische Werk VFW-614
(5) Illyushin Aviation IL 96T
(6) Bristol Aircraft Britannia 305
(7) Handley Page Herald Type 300

(8) Avions Marcel Dassault--Breguet Aviation Mercure 100C
(9) Airbus Caravelle
(10) Lockheed L-300
3. Change in Operator Compliance Date for Auxiliary Fuel Tank ICA
    As stated in the NPRM preamble, the current FTS requirements
mandate that ICA must be developed for the ``actual configuration of
the fuel tank systems of each affected airplane.'' The fuel tank ICA
must address the fuel tank system as defined by the airplane's type
certificate (TC), any supplemental TCs, and any field-approved
incorporated auxiliary fuel tank systems.
    In the NPRM preamble, we acknowledged that the original wording of
the Fuel Tank Safety Rule proved to be unclear to many in the industry.
We proposed revised regulatory language in the NPRM to clarify the
original intent. The revision clarifies that holders of STCs, as well
as TC holders for the affected airplane models, must develop ICA as
required by SFAR 88, and that the operator is required to develop
maintenance instructions for field-approved auxiliary fuel tanks. The
clarified language regarding field-approved auxiliary fuel tanks was
included in paragraphs 91.1507(b), 121.913(b) (the number of proposed
Sec.  121.913 has been changed in this final rule to Sec.  121.1113),
125.507(b), and 129.113(b) of the NPRM. Those paragraphs require
operators to develop and submit to the FAA Oversight Office proposed
ICA by December 16, 2007 to address their field-approved auxiliary fuel
tanks.
    While the referenced paragraphs were clarifications and not newly
proposed requirements, industry has expressed uncertainty regarding the
scope of effort required by operators. As that uncertainty will not be
completely addressed until issuance of this rule, which will provide
the necessary clarification, we think it is appropriate to provide
additional time for operators to develop and submit auxiliary fuel tank
ICA proposals to the FAA Oversight Office. We have decided to extend
the compliance date for these operator submittals to June 16, 2008.
This will allow additional time for operators to conduct the necessary
analyses and develop appropriate ICA, or contract with other experts to
perform this work if needed. The June 16, 2008 date will also allow
adequate time for the FAA's Oversight Office to review and approve the
operator-developed ICA and for the operators to revise their
maintenance programs accordingly by December 16, 2008.
4. Original Configuration and Auxiliary Fuel Tanks
    United Airlines referred to the statement in the NPRM that new
maintenance programs must be developed based on the actual
configuration of the aircraft. It asked if this is intended to include
only major alterations (STCs), or minor alterations affecting wiring
systems as well.
    The commenter refers to a portion of the NPRM discussing
operational requirements of the Fuel Tank Safety Rule. As explained in
the NPRM, we are revising these requirements to eliminate reference to
the ``actual configuration'' of the fuel tank system. Instead, these
requirements clarify that operators' maintenance programs must address
the fuel tank system of the airplane as originally configured and
auxiliary fuel tanks later installed. All auxiliary fuel tank
installations are considered major alterations.
    On a related issue, under the operational rules adopted as part of
the Fuel Tank Safety Rule (Sec.  121.370(b)), operators were required
to revise their maintenance programs to include fuel tank safety
instructions, regardless of whether TC and STC holders provided such
revisions, as required by SFAR 88. In this final rule, we revise these
operational requirements to require that operators revise their
maintenance programs to incorporate fuel tank ICA developed by TC
holders, ICA developed by the operator for field-approved auxiliary
fuel tanks, and ICA developed by STC holders, if any. The effect of
this change is that, except for auxiliary fuel tanks installed under
field approvals, operators are not required to develop ICA to comply
with this rule; they are only required to revise their programs to
incorporate ICA developed by others. Therefore if an STC holder does
not develop ICA, then the operator has no further action to comply with
the operational rule for that STC design configuration. However, if it
appears STC holders will not provide timely support for the operators,
we will consider enforcement action.
5. Inspection and Maintenance Program Terminology
    Boeing commented that Sec.  125.507 refers to a fuel tank system
inspection program; whereas the companion sections in parts 91, 121,
and 129 refer to a fuel tank system maintenance program. It asked
whether this difference was intentional, and, if so, what is the
purpose of the difference.
    Boeing identifies a longstanding difference in terminology between
the regulations applicable to air carrier operations (parts 121 and
129) and other operations (parts 91 and 125). For air carriers, we
commonly use the term ``maintenance program'' to refer to the required
program for inspection and maintenance of aircraft (see Sec. Sec.
121.367 and 129.14). For other operations, we use the term ``inspection
program,'' which is typically narrower in scope than the programs
required of air carriers (see Sec. Sec.  91.409 and 125.247). For
purposes of this rulemaking, the requirements for the two types of
programs are the same. As Boeing notes, we have not always been
consistent in our use of this terminology.

H. Regulatory Evaluation

    The final regulatory evaluation that accompanies this final rule
can be found in the docket. In response to comments, we have revised
our cost and benefit estimates in several instances from those included
in the initial regulatory evaluation.
1. Engine Costs
    GE commented that new rules invariably involve additional
engineering work on the first certification program to comply. There is
often redesign required partway through the program, especially when
airplane rules are being applied to engine components, which are
designed in advance of the airplane. GE estimated additional costs of
understanding proposed subpart H and redesigning engine wiring
accordingly at $3,000,000 to $7,000,000 for the first certification
program only, and this figure doesn't include additional costs
identified by regulation.
    We accept this estimate and incorporate this general engineering
cost into the costs estimated in our final regulatory evaluation. To
estimate total general engine design costs to the industry, we use a
median of $5 million and multiply it by the number of engine
manufacturers (5) to arrive at total costs of $25 million ($23.4
million present value using a discount rate of 7%).
2. Wiring System Safety Analysis for Engines
    GE commented that the proposed Sec.  25.1705 (now Sec.  25.1709)
requirement for an independent safety analysis of wiring systems would
add to the certification cost of each new program. The incremental cost
would be similar to the existing cost of a safety analysis.
    Since the original comment, the engine manufacturer has provided
additional supporting data. The FAA agrees and incorporates this data
into this regulatory evaluation. The total estimated cost to this
engine

manufacturer as a result of this requirement is $6.6 million ($3.2
million present value).
    We have revised our cost evaluation based upon this estimate. Using
this annual estimate for one manufacturer, we have developed an
industry estimate. The corresponding total cost for five engine
manufacturers is $31.5 million ($14.7 million present value) and is
contained in the final regulatory evaluation.
3. Labor Rates
    GE commented that the estimated fully burdened hourly labor cost of
$55.18 for engineers is too low because it doesn't include employee
benefits. GE contended that including benefits would bring labor costs
to $73 per hour. Boeing commented that in this proposal and the
proposed rule on ``Reduction of Fuel Tank Flammability in Transport
Category Airplanes'' there were differences in the fully burdened rates
used for aviation engineers and mechanics. Boeing requested that costs
associated with this proposal be reevaluated using the more realistic
rates contained in Docket No. FAA-2005-22997.
    We have updated the wage rates in our final regulatory analysis. In
the final regulatory evaluation we use $75 as the burdened hourly cost
for an engineer and $50 as the burdened hourly cost for a mechanic. A
detailed discussion can be found in the ``key assumptions & labor
rates'' section of the final regulatory evaluation.
4. The Regional Airplane Fleet
    The Regional Airline Association (RAA) requested we revise the
cost-benefit analysis because it cites no regional transport category
airplane accidents or incidents to indicate that concern over wiring
systems is comparable for all airplanes affected by the proposed rule.
The commenter said that wiring system malfunctions are generally unique
to a specific fleet type, and the review of the NTSB database, most of
the EAPAS NPRM Supplemental Material, and ATSRAC's review were limited
to wiring discrepancies in airplanes with passenger seating of 100
persons or more. The RAA stated that differences in the regional
airline fleet would justify a less stringent design review. For
example, no airplanes with 50 seats or less have in-flight
entertainment systems. Regional airplane galleys generally have no more
than a single coffee maker, and almost none have ovens, so the
electrical loads and wiring required to support this type of service is
minimal. Regional operators are less likely to revise seating or make
other modifications to the cabin from their original configuration. The
commenter said that inspection of regional airplanes affords fewer
opportunities to disturb existing wiring, since accessibility into
locations where wire bundles may be inadvertently damaged is limited.
It noted that the turboprop fleet, in particular, operates at altitudes
and locations where emergency landings can be readily accomplished.
    The RAA said its members will incur greater costs than the larger
fleet because regional operators must amortize compliance costs over a
significantly smaller seat revenue base.
    Smaller transport airplanes do, and will continue to, exhibit the
same EWIS degradation issues found in larger transports in absence of
this final rule. Since the NPRM, the NTSB has issued Safety
Recommendations A-06-29 through -35 pertaining to fires on one
particular model of regional jet. In the six months between October
2005 and March 2006, there were a total of six fires on regional jets.
A seventh fire occurred prior to that six month period. In addition to
the danger posed by the resulting fires, the NTSB stated that two of
the incident airplanes temporarily lost all flight displays. The
investigation by the NTSB revealed that all of the fires originated
from the same electrical component \8\ and that the fires were caused
by moisture-induced short circuits between the electrical terminals of
the contactors. If the requirements contained in this final rule had
been in effect, the type of failure that was the cause of these seven
fires would not have occurred. This is because several of the new
requirements directly address the design issues that lead to the fires.
The following bullets address the specific requirements and the reason
the failures would have been prevented.
---------------------------------------------------------------------------

    \8\ An electrical contactor located in the avionics compartment
beneath the floor and slightly aft of the captain's seat.
---------------------------------------------------------------------------

     Sec.  25.1701 provides a regulatory definition of an EWIS.
The portion of the electrical contactor that was the cause of the
failure would have been considered an EWIS component.
     Sec.  25.1703 requires the proper selection of EWIS
components. Although the electrical contactor was qualified to perform
its intended function by the current Sec.  25.1301, the new
requirements of Sec.  25.1703 would have gone further by requiring a
specific assessment of the component to ensure that it is installed
correctly and operated within its limitations (Sec.  25.1703(a)(2)) and
that if located in a known area of moisture accumulation (which it is)
that it be protected to minimize any hazardous effects due to moisture
(Sec.  25.1703(d)).
     Sec. Sec.  25.1707 and 25.1709 would have prevented
redundant power sources for essential airplane systems from receiving
power from the same electrical contactor, as was the case with this
aircraft design. Section 25.1707 requires that adequate separation
between power sources be provided and that they not interfere with each
other. Section 25.1709 requires an EWIS safety assessment to
demonstrate that failures cannot occur unless they can be shown to be
either extremely remote or extremely improbable, depending on the
severity of the failure.
    The regional jet (RJ) fleet uses the same EWIS components, design
and installation methods, and maintenance techniques as the larger
transports. Although RJs typically do not have in-flight entertainment
systems and the same type of galleys as the larger transports, they
share many systems that have historically exhibited EWIS-related
problems. Examples are the power distribution systems, cargo areas,
hydraulic systems, wheel wells, and high density areas such as the
cockpit and avionics racks. On average, RJs fly more cycles per day
than larger transports. So while their life cycle might be shorter in
years than the larger transports, because their systems are cycled on a
more frequent basis, their EWIS are subjected to more exacerbating
factors causing degradation in a shorter period of time. We have
reviewed SDR data spanning a five year period to specifically identify
EWIS failures on RJs. Although the NTSB findings alone might
demonstrate the underlying necessity of this final rule, in response to
comment, the FAA has evaluated the annual number of wiring SDRs
specifically by aircraft category. The final regulatory evaluation
demonstrates that the number of EWIS failures for regional jets and
large transports should not be examined separately.
5. Measure of Effectiveness
    The RAA requested that we validate use of a 68% effectiveness
measure in the cost-benefit analysis. It noted that the benefit
analysis suggests that by adopting the proposed regulations, ``industry
will be able to detect 68 percent of EWIS problems before a failure
occurs.'' This was based on an FAA review of service difficulty reports
(SDR) for EWIS failures for the period 1995-2002 and expert judgment.
The commenter said that it could not determine the validity of the SDR
analysis, but that NTSB data over the last 10 years does not show the
wiring

malfunctions projected by this benefit analysis. The RAA contended that
the SDR review and expert judgment of SDR data does not reflect the
types of malfunctions that would cause unscheduled landings or non-
fatal and fatal events, and that the effectiveness measure for this
proposal is no better than 23%.
    Our evaluation was based on a review of thousands of SDR entries
and on the ATSRAC-produced Intrusive Inspection Report. In the NPRM, we
did not assume that the rule would be 100 percent effective. Instead we
measured expected effectiveness at 68%. The judgment used to evaluate
EWIS failures in the regulatory evaluation refers to conclusions
reached by experienced FAA and industry engineering and operational
personnel reviewing operator-reported data and applying their
considerable expertise to determine operational impacts of the EWIS
conditions identified. In response to comment, we have re-evaluated the
expected effectiveness and lowered it to 60%. Total potential benefits
are multiplied by the 60% effectiveness measure to arrive at the
expected total benefits. The initial and final regulatory evaluations
provide a detailed description of how we arrived at 68% and 60%
effectiveness rates. Despite the effectiveness measure decreasing from
68% (in the NPRM) to 60% (in the final rule), the total benefits
increase. This is because the wiring problems were much greater than we
originally estimated. Because of our comprehensive examination since
the NPRM, we learned that there are more unscheduled landings and
operational problems occurring from electrical wiring failures than
originally included in our calculations. Since the NPRM we have
analyzed all of the most recent data available.
    Existing rules require operators to submit reports notifying the
FAA of the occurrence or detection of failures, malfunctions, or
defects in systems and components of aircraft. These service difficulty
reports (SDR) are filed when a system, component, or part of an
aircraft, power plant, propeller, or appliance fails to operate in the
normal or usual manner.
    The FAA reviewed all of the most recent reports from operators. The
most recent reports from operators demonstrate that failures of the
electrical wiring interconnection systems (EWIS) are much greater than
previously anticipated and estimated in the NPRM.
    In our analysis, we quantify and estimate the economic impact that
will occur when these electrical failures and malfunctions are averted.
Although we categorize and quantify averting such failures as
``operational benefits,'' the occurrence of these failures has a direct
effect on passenger safety and such failures are often precursors to
more serious events.
    In the NPRM we forecasted 1,118 unscheduled landings caused by
wiring problems; of which 760 (68%) would be averted. In addition to
the averted unscheduled landings, we estimated 968 events would cause
delays; of which 658 (68%) would be averted.
    Based on the most recent data and our comprehensive review, in the
final rule, we estimate roughly 2,202 unscheduled landings; of which
1,321 (60%) will be averted. In addition, there will be 13,649
electrical wiring failures that will have an operational impact; of
which 8,189 (60%) will be averted.
    Accordingly, operational benefits increased in the final rule from
$192 million (NPRM estimate) to $506 million.
    The revised safety benefits as reflected in the final rule are
based on a revised effectiveness estimate of 60% and an updated
forecast showing the trend of operators to use smaller aircraft with
higher load factors. This caused an overall decrease in the estimated
safety benefits as reflected in the final rule. A detailed discussion
of the effectiveness determination can be found in the regulatory
evaluation.
6. Operational Impacts
    UPS requested that we remove the operational improvements portion
of the benefits calculation and restrict cost calculations to tangible
safety benefits versus direct compliance costs. The commenter stated
that this change would reduce the overall benefit calculation by $192.3
million.
    The commenter contrasted the following to justify this request:
     The proposal calculates that averting a 3.5 hour delay
will save airlines $35,739.
     The calculation in the proposed rule for Fuel Tank
Flammability Reduction (FTFR), dated November 2005, uses a delay cost
of $24.43 per minute, so a delay of 3.5 hours yields an estimated cost
of $5,130 per event.
    UPS stated it is notable that the FAA cites the benefit of an
averted delay in one proposed rule, and the cost of a similar delay in
another. Both were open for comment at the same time. The commenter
contended that the value of operational improvements is highly
subjective, inconsistent, doesn't yield accurate results, and is
specific to each operator.
    Boeing commented that it is unusual that the FAA has included
averted delays, unscheduled landings, and failures of in-flight
entertainment systems, which are essentially airline economic concerns,
as part of the benefits accruing from the proposed rule. Boeing noted
that the FAA included these benefits because, to quote the NPRM,
``delays and unscheduled landings contain safety risks for passengers
and crew and increase the likelihood of a more serious event.'' This
commenter questioned the relationship between these non-normal but safe
events. It disagreed with their inclusion in this analysis as a method
of justifying rulemaking. Boeing stated that in past endeavors, the FAA
has not permitted Boeing use of these events as benefits.
    We have decided to retain the operational impacts estimated in the
benefit calculations. As prescribed by the Office of Management and
Budget (OMB), the regulatory evaluation should attempt to quantify all
potential real incremental benefits to society in monetary terms, and
this includes operational improvements that would result from adoption
of these requirements. We have clarified our terminology since the
NPRM. This final rule evaluates operational impacts.
    The operational impacts (``delays'' in the NPRM) that are
quantified in the final regulatory evaluation of EAPAS/FTS cannot be
compared with delays estimated in the Fuel Tank Flammability Reduction
NPRM (FTFR). The estimates contained in FTFR include crew costs, ground
handling costs, and fuel costs. The operational impact benefits for
EAPAS/FTS evaluate impacts from operator equipment malfunctions and
failures in wiring as reported by operators in SDRs.
    Operational impacts caused by EWIS failures are more serious and
have a higher cost impact than the delays characterized in the FTFR
NPRM. Wiring failures have an immediate impact on operations and the
model estimates them accordingly. Fuel tank inerting problems,
addressed in FTFR, are not necessarily fixed immediately. The
operational impact estimated in the regulatory evaluation for this rule
uses operator reports of failures, malfunctions, or defects of systems
and components of the aircraft. The five years of data and accompanying
analysis is included in the final regulatory evaluation and in appendix
C. These types of failures are more serious (in terms of cost and time)
than the delay of $24.43 per minute as reported by ATA and used in that
evaluation. The operational impacts (as

estimated in the final regulatory evaluation) of wiring failures have
safety impacts and increase the likelihood of a more serious event.
7. Training Costs
    GE commented that training addressed in proposed AC 120-YY is
commercially available, at $60 per employee trained, to be repeated
biannually. It stated that costs of having employees occupied in
training rather than production were not factored into our estimate. GE
said the training it investigated involves 17 modules, at an average of
30 minutes each, resulting in 8.5 hours per trained employee,
biannually, in addition to the $60 /employee/year. GE said the cost to
operators and service shops of providing training is therefore $308/
employee/year. U.S. Airways stated that the average annual cost of
$131,108 for developing a training program seems to be significantly
below actual costs. United Airlines asked if operators will be expected
to follow proposed AC120-YY. It says ``target level one'' training
alone takes 40 hours and the three hours quoted in the NPRM seems
extremely low.
    The FAA agrees that the required training might be available
commercially. We base our cost estimates on module C of AC 120-94,
which requires less intensive training than the program identified by
commenters. The training required by this final rule does not apply to
production personnel, but to maintenance and inspection personnel only,
as required by Sec.  121.375. Therefore we did not consider the cost of
having production personnel in training. We believe that the training
covered by Module C is the minimum additional training required to
comply with the new EWIS inspection requirements. We estimated the time
to conduct this training at 3 hours for target groups 1, 2, 4, and 6,
as provided by ATSRAC and stated in the initial regulatory evaluation.
Training for the remaining modules and target groups is voluntary and
not required for compliance with this final rule. No changes were made
as a result of these comments.
    RAA stated that using care when working around wiring, being
knowledgeable about electrical systems, and teaching technicians that a
maintenance/alteration task is not complete until the area is
thoroughly cleaned are simply common sense and need not be mandated.
The commenter expressed confidence these maintenance practices already
exist among its members, and said that specific retrofit requirements
can be more efficiently mandated by Airworthiness Directives.
    RAA said one member suggested it would enhance its training not on
how to develop inspection programs, but as a preventative maintenance
aide for technicians. The commenter suggested the FAA (with industry
assistance) issue an ``Electrical Systems Installation & Repair
Standard Practices Hand Book'' that supplements or replaces the
sections in AC 43.13, along with video training modules. RAA suggested
that training on concepts like proper routing of wire bundles with
sufficient supports that are not so tight as to increase the
possibility of chafing within the bundle would be more beneficial than
inspecting after the fact. The commenter said that availability of
quality training to many technicians will result in a cultural change
in the industry that can roll over to other practices.
    The final regulatory evaluation clearly shows that the benefits
exceed the costs of the proposed EWIS maintenance requirements. As
stated in the NPRM preamble discussion, investigations of previous
accidents and examinations of other airplanes shows that deteriorated
wiring, corrosion, improper wire installation and repairs, and
contamination of wire bundles with various contaminants are common
conditions in today's transport category fleet. Current maintenance
practices do not adequately address wiring components, wiring
inspection criteria are too general, and unacceptable conditions, such
as improper repairs and installations, are not described in enough
detail in maintenance instructions. We commend the RAA member airline
for volunteering to enhance its EWIS training program and we encourage
other companies to do the same. A complete EWIS training course,
developed by ATSRAC, is contained in AC 120-94. Also, we have produced
a course on good wiring practices which is available to the public
through our Oklahoma City training center.
8. Costs for EZAP Analysis and Inspection of Engines
    GE commented that reviewing an engine manual to identify tasks that
touch or approach wiring is estimated at 160 hours. Checking a manual
for the 41 items listed on pages 10-11 of proposed AC120-XX (this
material is now in the DAH EZAP AC), for each of the 14 harnesses per
engine, is estimated at 40 hours. It estimated compliance costs to GE
at $438,000. GE stated that incorporating all 41 elements on pages 10-
11 of proposed AC120-XX into a C-check would increase C-check time by a
minimum of 1 day, resulting in 15,000 extra days of maintenance a year
for operators, at a cost of $150 million annually.
    Our final regulatory evaluation accounts for additional cost
estimates in part due to the comments received from the engine
manufacturer. Since we are not making any changes to part 33, engine
manufacturers will not be required to perform an EZAP. The FAA
disagrees with GE's estimate because airplane manufacturers have
already completed EZAP analyses on existing airplanes without support
from engine manufacturers.
    We do not concur with GE's statement that performing an EZAP on
engine-mounted EWIS components will result in an additional day being
added to the length of a C-check (assuming that the frequency of the
maintenance tasks require them to be completed on a C-check cycle).
Based on data provided by one airplane manufacturer, we estimate that
an additional 1 to 3 inspection tasks per engine will be necessary
based on the results of applying EZAP to the engine zone. Since we
anticipate that these additional tasks will be incorporated into
scheduled maintenance down-times, no additional time for gaining access
to the engines will be required. We expect that these additional tasks
will be performed during scheduled maintenance visits and the
corresponding costs are contained in the cleaning, inspection, and
downtime sections of the regulatory evaluation.
    GE contended that supporting manufacturer compliance with proposed
subpart I (now part 26) will involve an estimated 240 work days, or
$140,000, plus travel expenses of $100,000, per program. Even with cost
savings for technically similar engines, GE said its costs for the DAH
requirements would be $3,600,000.
    Airplane manufacturers have already completed EZAP analyses on
several different models of aircraft, and engine manufacturers have not
provided support for these activities. We are not making any changes to
part 33. Engine manufacturers are not required to support airframe
manufacturers in complying with this final rule for either existing or
future certification programs.
9. Engine Costs for Sec.  25.1362
    GE commented that costs of Sec.  25.1362 were not addressed. As
discussed previously, this rule requires that a suitable electrical
supply be provided to those services required for emergency procedures
after an emergency landing or ditching. GE stated that because very low
levels of electrical energy can ignite

fuel under laboratory conditions, it is not clear that any electrical
supply to the fuel shut-off valve could be predicted to meet this rule.
GE suggested that one way to comply would be by substituting a
mechanical cable for the electrical signal to the engine fuel shut-off
valve. It stated that such a cable, extending from the engine to the
wing/body join, would increase costs by approximately $20,000 per
engine installation. It would also be less reliable, leading to an
incremental unreliability of 0.4 cable seizures per million attempted
engine shutdowns, and incremental maintenance costs. GE estimated an
average annual cost to operators of $1,000,000.
    We do not concur with GE's cost estimate for Sec.  25.1362
compliance. GE interpreted the requirement to mean that electrical
faults must be minimized to prevent them from causing a fire. The FAA's
intent here is to ensure that there is necessary electrical power
available to allow the emergency service equipment, such as a fuel
shut-off valve, to operate after an emergency landing or ditching. Also
as discussed previously, we have revised final Sec.  25.1362 to clarify
this point. We made no changes due to this comment.
10. Wire Labeling Costs
    GE commented that the cost estimate for the labeling requirements
of Sec.  25.1711 appears based on mechanics adding labels during final
assembly. GE stated that identifying wires at 15-inch intervals
requires many more than the estimated 3,500 labels per airplane. Since
fly-by-wire aircraft typically contain 100 miles of wiring, a label at
15-inch intervals equals over 422,000 labels per aircraft. GE stated
that manufacturing wire with labels is more practical but would require
that manufacturers invest in more tooling, plus drawing changes to
harnesses and cables. GE estimated its cost at $9,300,000 over 25 years
or $370,000 per year. Spectrum Technologies contended that the burden
for wire identification labeling was significantly underestimated,
particularly in relation to heat shrink labels and probably other
types. The NPRM estimates a wire identification time of 30 seconds per
label. Spectrum said that, based on industry practice, the time for
heat shrink labeling is more like 240 seconds per sleeve.
    In response to the estimated cost of $0.05 per label, Spectrum
contended that the typical figure for industry brand name heat shrink
labels is more like $1.50, depending on size. It said that the total
cost of adding just one heat shrink sleeve can be calculated as $2.88.
    The new rule does not require that additional labels be manually
added to wiring. It only requires additional information to be included
in the wire labeling that already exists. It appears that the commenter
assumes that there are no labeling requirements in effect today.
Section 25.1301 already requires that components be identified. The
requirement contained in this final rule expands on those requirements
by imposing additional labeling requirements. Complying with Sec.
25.1711 will be a matter of providing additions to, or changing the
type of, information already on the EWIS labels that exist today. Based
upon existing practices, our analysis estimates this additional cost.
    Spectrum Technologies commented on the technical and economic
advantages of a specific prescriptive means of compliance. Based on
comments since the NPRM, we have verified our estimates. While we
disagree with the specific estimates in the illustrative comment, we
believe that manufacturers will demonstrate compliance using the most
efficient and cost effective technology available.
11. Additional Certification and Operator Costs
    Boeing and AIA/GAMA commented that we failed to account for
additional certification costs in complying with the new requirements
in subpart H and supporting all subpart H requirements for amendments
to existing type certificates. Boeing maintained that the FAA should
account for these costs, as well as:
     Additional ``ongoing coordination necessary to ensure
ongoing communication and cooperation between the applicants and the
FAA'' described in draft Advisory Circular 25-XX.
     Costs borne by DAHs to perform the EZAP process detailed
in draft Advisory Circular 120-XX (now in the DAH EZAP AC).
     Most importantly, increased costs associated with enhanced
maintenance of wiring on all in-service airplanes.
    Boeing asked that we include these costs in the analysis to get a
true understanding of the burden associated with the projected benefits
of the proposed rule. AIA/GAMA requested we include costs to operators
for enhanced EWIS maintenance and updated labor rates for engineers as
well as these additional items:
     Additional DAH manufacturing costs for future part 25 TC
and STC products that include new subpart H (regardless of seating
capacity).
     Training for maintenance personnel. This should include
existing airplanes subject to new Sec.  121.911 (now Sec.  121.1111),
Sec.  125.507, and Sec.  129.111 EWIS ICA requirements as well as
future airplanes that include new subpart H and associated EWIS ICA
requirements.
     Additional general aviation operator (part 91/135) costs
associated with enhanced maintenance of EWIS on all future airplanes
that include new part 25 subpart H and associated EWIS ICA
requirements. This should consider additional airplane downtime and
necessary training for maintenance personnel.
     Additional repair station costs to update FAA-approved
maintenance training manuals and provide training to their maintenance
personnel.
    In response to these comments, the FAA estimates the costs for
ongoing coordination necessary to ensure ongoing communication and
cooperation between the applicants and the FAA. Neither the preliminary
nor final regulatory evaluation includes cleaning and inspection costs
for deliveries of future aircraft operated in parts 91 and 135 because
there is no operational requirement to do so. Other than the increased
cost of EWIS component identification addressed in the regulatory
evaluation, we believe that there will be minimal additional
manufacturing costs associated with complying with the new EWIS
certification requirements.
    As in the preliminary regulatory evaluation, we continue to
estimate the following costs:
     Subpart H TC certification costs.
     Subpart H STC certification costs.
     EZAP costs for existing TCs, future TCs, and future STCs.
     SWPM update costs.
     EWIS identification costs for TCs and STCs.
     Training costs for maintenance personnel.
     Planning costs to part 121 operators.
     Cleaning/inspection costs to part 121 operators.
     Downtime costs to part 121 operators.
12. Previous Rulemaking
    The RAA requested that the cost-benefit analysis be revised to
account for previous rulemaking actions that mitigate likelihood that
an accident/incident similar to those that prompted this rulemaking
action will occur in the future. The RAA requested that if benefits of
a revised cost-benefits analysis are less than the cost of adopting the
operating rule, proposed

part 121 & 129 affecting the current fleet be withdrawn.
    The commenter considered the benefits analysis a ``double count,''
or a count of the same fatalities as a benefit in future accident
avoidance as were counted to justify previous rulemaking. It stated
that industry has spent millions of dollars in fleet retrofit and
inspection improvements, mostly mandated by rulemaking, and there has
been a dramatic decrease in the accident rate despite increased fleet
growth. RAA said the estimated 5.3% ratio of accidents to incidents has
changed dramatically in the last 10 years, but the benefits analysis
does not acknowledge this.
    GE stated that the benefit claimed for this rule does not account
for previous rules introduced to address the MD11 in-flight fire and
accident, specifically the rule on cabin insulation materials. GE said
that the effect of that rule was to prevent wire arcing from
propagating into a fire within the pressurized fuselage, by removing
flammable materials. The commenter argues that since significant
measures have already been taken to prevent a recurrence of this kind
of accident, the benefit claimed for the EAPAS rule package should be
reduced accordingly, but says is not clear whether this has been done.
    The cost-benefit analysis evaluates the risk of passenger deaths
associated with wiring failures. We analyze the historical number of
wire failures and evaluate them in the context of this rulemaking. The
accidents and incidents listed in appendix B of the preliminary
regulatory evaluation included neither TWA 800 nor Swissair 111, so we
have not ``double counted'' benefits as the RAA contends.
    Although we have issued various ADs and other rules dealing with
flammability of insulation blankets, those rules do not address the
issue of wire contamination that can also be a source of fuel for on-
board fires. Adoption of EAPAS will help minimize likelihood of an on-
board fire due to wire contamination and wire failures.
    We continue to observe an overall increase in wire-related failures
as demonstrated in EWIS SDRs, accidents, and incidents. Although wire
type and insulation materials have evolved over the years, the means to
design, install, and maintain EWIS remain much the same. To reduce
occurrences of wire-related incidents and accidents, it is necessary to
adopt the requirements contained in this final rule.
13. Relevance to the Current Fleet
    The RAA requested that we revise the cost-benefit analysis to
determine relevance of the ASTRAC analysis to the current fleet. It
stated that the analysis and recommendations were largely based on
inspections of wiring on decommissioned airplanes that at the time
(1998) were older than 20 years (DC-8, DC-9, DC-10, 727, etc.). The RAA
estimated that those airplane wiring systems were certified at least 50
years ago, and since then aircraft wiring systems have improved. It
further stated that the analysis estimates such airplanes represent
less than 1% of the current fleet. The commenter asked how we can imply
that ASTRAC's analysis has any relevance to today's fleet.
    The RAA also questioned the validity of using a 25-year period for
determining benefits. It questioned projecting 25 years into the future
to justify benefits for a retrofit rule and stated that all other
retrofit rules have projected 10 to 20 years. The RAA called it
unrealistic to use an accident/incident review for older aircraft
projected to be retired from service before the end of the 25-year
amortization period.
    We believe that ATSRAC's analysis is relevant to today's fleet. The
regulatory evaluation cites ATSRAC's non-intrusive inspection report
finding 3,372 total discrepancies during the non-intrusive wiring
inspections of 81 airplanes. The ``effectiveness measure'' looks at
continuing failures, malfunctions, or defects in the current fleet as
reported by operators, and evaluates them with respect to the Intrusive
Inspection Report. This final rule will change the certification,
design, installation, and maintenance practices for EWIS, which, up to
this time, have changed very little since the jet age began. In
addition, the physical environments in which wires are installed and
the types of hazards they are exposed to are very similar regardless of
airplane age. At the same time, airplane designs have become more
vulnerable to EWIS safety problems because they are more dependent on
electrical systems and less dependent on mechanical systems, as in the
case of electronic flight control systems.
    We chose the 25-year benefit period because we expect, on average,
that a newly manufactured airplane would be in service for that period
of time. There will also be airplanes delivered in the next 25 years
that are impacted by these requirements. As stated in the preliminary
regulatory evaluation the 25-year analysis parallels the expected
useful life of an aircraft impacted by this proposal.
14. Accidents Indirectly Initiated by EWIS
    The NTSB was concerned that the cost-benefit analysis does not
account for indirect EWIS-initiated accident causes, such as those that
occurred during the June 6, 1992, accident involving COPA flight 201
that crashed near Tucuti, Panama. For that accident, an instrument's
gyroscope wire was believed to have frayed and shorted, leading to
erroneous instrument indications and the pilots' loss of control of the
airplane. The Board believes that the number of EWIS-related accidents
and incidents that can be prevented will exceed that predicted by the
FAA.
    We acknowledge that functional effects of wiring failures may have
contributed to additional incidents and accidents. Although additional
benefits could be estimated for indirect causes, we have focused our
analysis on direct causes only.

I. Harmonization Changes to Transport Category Certification Rules
(Part 25)

1. FAA/JAA (Joint Aviation Authority) Harmonization
    At the time the EWIS certification requirements in this final rule
were being developed, several existing part 25 certification
requirements were also undergoing revision as part of a separate joint
harmonization effort with the European JAA.\9\ These rules were the
result of an effort to develop a common, or ``harmonized'' set of
standards between 14 CFR part 25 and JAR-25, which was then the
European counterpart to part 25. Because this harmonization effort was
essentially complete when drafting of this final rule began, the
harmonized rules were used as the baseline for the new EWIS
certification rules. The harmonized rules are finalized here. This
final rule also further revises several of the harmonized rules to
accommodate the new EWIS requirements.
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    \9\ The JAA is the Joint Aviation Authority of Europe and the
JAR is its Joint Aviation Requirements, the equivalent of our
Federal Aviation Regulations. In the time since these rules were
developed, in 2003, the European Aviation Safety Agency (EASA) was
formed. EASA is now the principal aviation regulatory agency in
Europe, and we intend to continue to work with EASA to ensure that
this rule is also harmonized with its Certification Specifications
(CS). But since the harmonization efforts involved in developing
these rules occurred before EASA was formed, it was the JAA that was
involved with them. So while the JAR and CS are essentially
equivalent, and in the future we will be focusing on the CS, it is
the JAR that will be referred to in the historical background
discussions in this final rule.
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    We received no comments about sections 25.899, 25.1309, and
25.1310.

They are finalized here in the same form in which they were proposed.
2. Circuit Protective Devices (Sec.  25.1357)
    Section 25.1357 specifies standards for use, functional
requirements, and installation requirements for electrical circuit
protective devices. These standards protect the airplane's wiring from
electrical faults or malfunctions. JAR paragraph 25.1357(d) contains a
requirement to provide sufficient spare fuses, formerly located in
paragraph (f). The reason the JAA moved this text from paragraph (f) to
(d) was to make it clear that the spare fuse requirement does not apply
to fuses that are inaccessible in flight. We are moving the spare fuse
requirement of paragraph (f) to paragraph (d) to harmonize with the JAR
requirement. This rule continues to address the underlying safety issue
by providing protection for the airplane's electrical system from
wiring faults or malfunctions, and by ensuring that there is no
confusion about use of spare fuses in flight.
    In addition to the harmonization changes we made to Sec.  25.1757,
we also added a requirement that airplane systems normally requiring
power removal have a power switch to accomplish this, instead of
relying on using the circuit breaker.
    Continental Airlines asked if the prohibition against circuit
breaker use as the primary means of power removal or reset during
normal operations applies to existing STC installations or to future
amendments to existing STCs.
    Section 25.1357(f) will not require an existing installed STC
system to be changed. As with any other change to the airworthiness
standards of part 25, whether future amendments to those STCs would be
required to comply with the requirements of Sec.  25.1357(f) would be
determined in accordance with Sec.  21.101.
    AIA/GAMA and GE requested that we clarify what is meant in Sec.
25.1357(f) by ``normal operation.'' They asked whether consideration
for the need of a switch extends to non-normal or emergency situations.
    It is not the intent of the requirement that every electrically
powered system in the airplane have a means to remove power other than
a circuit breaker. We distinguish between airplane systems normally
turned on and off during normal operations, such as passenger
convenience systems, and those systems normally powered at all times,
such as flight deck multi-function displays or the flight-management
computer. But if, for example, the flight-management computer requires
power cycling regularly as a part of normal operations, this system
would also be required to have a means to do this other than using
circuit breakers that are not specifically designed for use as a
switch. Non-normal or emergency situations do not need to be considered
when determining the need for a switch.
3. Precautions Against Injury (Sec.  25.1360)
    Section 25.1360 is a new rule requiring that the electrical system
and equipment be designed to minimize risk of electrical shock and
burns to the crew, passengers, and maintenance and servicing personnel
during normal operations. This rule adopts the current JAR standard and
is in line with current industry practice. It is unchanged from the
form in which it was proposed.
    AIA/GAMA and GE requested that the term ``maintenance'' in Sec.
25.1360 be limited to line maintenance.
    We infer from GE's comment that it wants Sec.  25.1360 amended to
revise the phrase ``maintenance personnel'' to read ``line maintenance
personnel.'' We are not adopting GE's request. We believe the intent of
the requirement is clear because of the phrase ``using normal
precautions.'' Maintenance personnel, whether working line or shop
maintenance, are trained to use caution when working on, or around,
live electrical circuits. Section 25.1360 requires, in part, that the
airplane's electrical system be designed so that shock hazards to
maintenance personnel are minimized when they are taking normal
precautionary measures to avoid shock hazards. We made no changes due
to this comment.
4. Electrical Supplies for Emergency Conditions (Sec.  25.1362)
    Section 25.1362 is a new rule that duplicates current JAR
standards. It requires that a suitable electrical supply be provided to
those services required for emergency procedures after an emergency
landing or ditching. The circuits for these services must be designed,
protected, and installed so that risk of the services being rendered
ineffective under these emergency conditions is minimized. Section
25.1362 has been changed from the form in which it was originally
proposed in order to clarify meaning, as discussed below.
    Boeing Wichita requested that we clarify what is meant by the words
``protected'' and ``minimized.'' Honeywell and GE asked that the second
sentence of the section be deleted. They said there is no clear
approach to providing electrical power to the fuel shut-off valve on an
engine or APU without potential for it being an ignition source after
an emergency landing. They suggested wording could be added to AC
25.1362-1X as follows:

    Use of the normal aircraft supply voltage has been found to
acceptably minimize the risk of fire.

    We do not agree to delete the second sentence of Sec.  25.1362. The
intent of the requirement is to prevent disconnection of the electrical
supply to the required services before the emergency procedures are
completed. The concern of this rule is not that the circuits are the
source of the fire but rather that they be capable of shutting off the
services that could contribute to the fire. We concur with Boeing
Wichita's request to clarify the intent of the requirements and we have
revised the final Sec.  25.1362 to do this. We have also revised the
associated advisory circular to clarify appropriate means of
compliance.
5. Electrical Appliances, Motors, and Transformers (Sec.  25.1365)
    Section 25.1365 is a new rule within the ``Miscellaneous
Equipment'' section of subpart F concerning design and installation of
domestic appliances, electrical motors, and transformers. The term
``domestic appliance'' is used to refer to those items placed on the
airplane to provide service amenities to passengers. Examples of
domestic appliances are cooktops, ovens, microwave ovens, coffee
makers, water heaters, refrigerators, and toilet flush systems. Section
25.1365 requires that domestic appliances be designed and installed so
that in the event of failures, the requirements of Sec. Sec.  25.1309
(b), (c), and (d) would be satisfied. It requires that galleys and
cooking appliances be such as to minimize risk of overheating or fire
and that they be installed to prevent damage or contamination of other
equipment from fluids or vapors resulting from spillage during use of
the appliances. It also requires that all electric motors and
transformers be provided with a thermal protection device unless it can
be shown that the circuit protective device required by Sec.
25.1357(a) would be sufficient to show compliance with requirements of
Sec.  25.1309(b). We made no changes to this rule.
    Honeywell and GE requested that we change the wording of Sec.
25.1365(d) to limit it to motors and transformers for domestic systems.
    We have decided against limiting applicability of Sec.  25.1365(d)
to domestic appliances. Our intent is that Sec.  25.1365(d) apply to
all motors and transformers on the airplane. While the NPRM only
discussed domestic appliances, the risk of smoke or fire hazard
addressed by this paragraph is

not limited to domestic appliances. The exception to this would be if a
circuit protective device is shown to negate the need for the thermal
protective device (as allowed by the rule language). We would
anticipate that engine- and APU-mounted motors and transformers would
fall into this category because adding thermal protection devices in
those cases could negatively impact the reliability of those devices.
The intended scope of this paragraph is apparent both from the rule
language and from the advisory material for that section:

    Section 25.1365(d) is broader in scope [than just domestic
appliances] and requires that all electric motors and transformers,
including those on domestic appliances, have a thermal protection
device * * *.

J. Additional Certification Rule Changes

1. Rules Changed to Accommodate Subpart H
    To create the new subpart H as the single place for the majority of
wiring certification requirements, some existing requirements applying
to wire were moved out of the rules in which they currently exist and
placed in the new subpart. The rules of which those EWIS requirements
were previously a part or which were the basis of a new EWIS