[Federal Register Volume 85, Number 194 (Tuesday, October 6, 2020)]
[Rules and Regulations]
[Pages 62993-63002]
[FR Doc No: 2020-21997]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-6141; Product Identifier 2015-NM-048-AD; Amendment
39-21237; AD 2020-18-16]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain The Boeing Company Model 767-200, -300, -300F, and -400ER
series airplanes. This AD was prompted by the FAA's analysis of the
Model 767 fuel system reviews conducted by the manufacturer. This AD
requires modifying the fuel quantity indicating system (FQIS) to
prevent development of an ignition source inside the center fuel tank
due to electrical fault conditions. This AD also provides optional
actions for cargo airplanes. The FAA is issuing this AD to address the
unsafe condition on these products.

DATES: This AD is effective November 10, 2020.
    The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of November 10,
2020.

ADDRESSES: For service information identified in this final rule,
contact Boeing Commercial Airplanes, Attention: Contractual & Data
Services (C&DS), 2600 Westminster Blvd., MC 110 SK57, Seal Beach, CA
90740-5600; telephone<PHONE_NUMBER>; internet https://www.myboeingfleet.com. You may view this service information at the
FAA, Airworthiness Products Section, Operational Safety Branch, 2200
South 216th St., Des Moines, WA. For information on the availability of
this material at the FAA, call<PHONE_NUMBER>. It is also available on
the internet at https://www.regulations.gov by searching for and
locating Docket No. FAA-2016-6141.

Examining the AD Docket

    You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2016-
6141; or in person at Docket Operations between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays. The AD docket contains
this final rule, any comments received, and other information. The
address for Docket Operations is U.S. Department of Transportation,
Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200
New Jersey Avenue SE, Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Jon Regimbal, Aerospace Engineer,
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des
Moines, WA 98198; phone and fax:<PHONE_NUMBER>; email:
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to certain The Boeing
Company Model 767-200, -300, -300F, and -400ER series airplanes. The
NPRM published in the Federal Register on May 4, 2016 (81 FR 26747).
The NPRM was prompted by the FAA's analysis of the Model 767 fuel
system reviews conducted by the manufacturer. The NPRM proposed to
require modifying the FQIS to prevent development of an ignition source
inside the center fuel tank due to electrical fault conditions. The
NPRM also proposed to provide optional actions for cargo airplanes. The
FAA is issuing this AD to address ignition sources inside the center
fuel tank, which, in combination with flammable fuel vapors, could
result in a fuel tank explosion and consequent loss of the airplane.

Comments

    The FAA gave the public the opportunity to participate in
developing this final rule. The following presents the comments
received on the NPRM and the FAA's response to each comment.

Support for the NPRM

    The Air Line Pilots Association, International (ALPA) and National
Air Traffic Controllers Association (NATCA) supported the intent of the
NPRM. Additional comments from NATCA are addressed below.

Request To Withdraw NPRM: No Unsafe Condition

    Boeing requested that the FAA withdraw the NPRM. Boeing suggested
that, by requiring center fuel tank FQIS wire separation for passenger
airplanes that have not incorporated a nitrogen generating system
(NGS), the NPRM specifically addresses airplanes regulated by the
European Union Aviation Safety Agency (EASA) and other civil aviation
authorities and the lack of a flammability reduction means (FRM) rule.
Boeing stated that because it considered the use of FRM (NGS) to
address unknown ignition sources as the final corrective action, Boeing
has not developed center tank FQIS wire separation service instructions
for passenger aircraft. Boeing stated that it believes no unsafe
condition exists and does not feel that the lack of FRM rule
harmonization should cause additional work and expense for airlines.
    The FAA disagrees with the commenter's request. The FAA determined
that an unsafe condition exists using the criteria in FAA Policy
Memorandum ANM100-2003-112-15, ``SFAR 88--Mandatory Action Decision
Criteria,'' dated February 25, 2003.\1\ That policy was used to
evaluate the noncompliant design areas identified in the manufacturer's
fuel system reviews and to determine which noncompliance issues were
unsafe conditions that required corrective action under 14 CFR

part 39. The FAA's unsafe condition determination was not based on an
assessment of average risk or total fleet risk, but rather was driven
by the qualitative identification of an unacceptable level of
individual risk that exists on flights that are anticipated to occur
with a preexisting latent in-tank failure condition and with a
flammable center fuel tank. For these reasons, and based on further
detailed responses to similar comments in the supplemental NPRM (SNPRM)
for Docket No. FAA-2012-0187 (80 FR 9400, February 23, 2015), and in
the subsequently issued final rule, AD 2016-07-07, Amendment 39-18452
(81 FR 19472, April 5, 2016) (``AD 2016-07-07''), which addressed the
same unsafe condition for Boeing Model 757 airplanes, the FAA has
determined that it is necessary to issue this final rule.
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Request To Withdraw NPRM: Unjustified by Risk

    Airlines for America and the Cargo Airline Association, in
consolidated comments (A4A/CAA), United Parcel Service (UPS) and FedEx
requested that the FAA withdraw the NPRM. A4A/CAA and UPS cited
comments submitted by Boeing to Docket No. FAA-2012-0187 in which
Boeing stated that the risk is ``less than extremely improbable.'' A4A/
CAA added that Boeing does not believe that an unsafe condition exists.
UPS stated that Boeing's comments demonstrate an unsafe condition does
not exist. A4A/CAA and UPS noted that they consider the Boeing comments
to be applicable to the airplane models in the NPRM. FedEx stated that
the proposed rule is not supported with a safety risk assessment and it
is therefore difficult to understand the validity and justification of
the proposed rule.
    UPS stated that an agency is required to consider all relevant
factors and articulate a satisfactory explanation for its action. UPS
noted that the FAA is apparently basing its decision to issue the AD on
historical Special Federal Aviation Regulation (SFAR) No. 88 design
reviews that have been superseded by the more recent Boeing analysis
and favorable operational experience in the years since the SFAR 88
reviews were completed.
    The FAA disagrees with the commenters' requests. The FAA notes that
Boeing's comments were addressed in the SNPRM for Docket No. FAA-2012-
0187 in the comment response for ``Request To Withdraw NPRM (77 FR
12506, March 1, 2012): Unjustified by Risk.'' As explained in that
comment response, in addition to examining average risk and total fleet
risk, the FAA examines the individual flight risk on the worst
reasonably anticipated flights. In general, the FAA issues ADs in cases
where reasonably anticipated flights with preexisting failures (either
due to latent failure conditions or allowable dispatch configurations)
are vulnerable to a catastrophic event due to an additional foreseeable
single failure condition. This is because the FAA considers operation
of flights vulnerable to a potentially catastrophic single failure
condition to be an excessive safety risk to the passengers on those
flights. The FAA has determined that the currently mandated SFAR 88
service bulletins, airworthiness limitations, and critical design
configuration control limitations do not adequately address the unsafe
condition identified in this AD and therefore it is necessary to issue
this final rule. The FAA has not changed this AD regarding this issue.

Request To Withdraw NPRM: No Safety Risk Assessment

    FedEx requested that the FAA withdraw the NPRM, stating that a
safety risk assessment was not included with the proposed rule. FedEx
quoted the NPRM to the fuel tank flammability reduction (FTFR) rule (70
FR 70922, November 23, 2005), which noted that the FAA had not
evaluated the risk to all-cargo airplanes because they are derivatives
of passenger airplanes. FedEx noted that the NPRM to the FTFR rule also
stated that the risk may be lower for all-cargo operations due to fewer
miles flown and more nighttime operations when temperatures are lower.
FedEx stated that its fleet utilization is only about 5 flight hours
per day, which would further lower the risk of accidents. FedEx
requested that the FAA provide a safety risk assessment for the Model
767 FQIS that justifies the proposed rule.
    The FAA does not agree to withdraw the NPRM. The FAA's
determination that an unsafe condition exists was not based on a
calculation of the total risk of an accident occurring in the life of
the fleet. Instead, the FAA's determination was based on an analysis
showing that numerous Model 767 all-cargo airplane flights will occur
with a latent FQIS in-tank failure, and that such flights will not
provide the minimum acceptable level of safety for transport airplanes
defined in FAA regulations and policy because they will not be fail-
safe for one additional electrical wiring fault. This was discussed in
detail in the SNPRM for Docket No. FAA-2012-0187, which addresses the
same issue for Model 757 airplanes, in the comment response for
``Request To Withdraw NPRM (77 FR 12506, March 1, 2012): Unjustified by
Risk.'' That comment response is applicable to this AD. The FAA has not
changed this AD regarding this issue.

Request To Withdraw NPRM: Probability Analysis Inconsistent With
Regulatory Requirements

    A4A/CAA and UPS requested that the FAA withdraw the NPRM. The
commenters stated that the assumption of a single failure regardless of
probability is inconsistent with 14 CFR part 25 regulatory
requirements. The commenters referred to the phrase ``regardless of
probability'' associated with single failures. A4A/CAA and UPS
acknowledged that the term is used with single failures in FAA Advisory
Circular (AC) 25.981-1C,\2\ ``Fuel Tank Ignition Source Prevention
Guidelines,'' but since that term does not appear in 14 CFR
25.981(a)(3), the commenters considered its use arbitrary, possibly
introducing additional requirements not included in that section. A4A/
CAA and UPS stated that the ``worst reasonably anticipated flight'' is
a flight with a latent FQIS failure and a high-flammability tank, and
this ``latent plus one'' failure--regardless of probability of a single
failure--is not consistent with 14 CFR 25.981(a)(3).
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    The FAA disagrees with the commenters' request. The FAA notes that
the commenters' assertion about the intent of 14 CFR 25.981(a)(3) is
incorrect based on both the language of the rule and on the published
rulemaking documents. The absence of a probabilistic qualifier in both
the ``from each single failure'' clause and in the ``from each single
failure in combination with each latent failure not shown to be
extremely remote'' clause in 14 CFR 25.981(a)(3) in fact means just
that--there is no probabilistic qualifier intended by the regulation.
The intent for single failures in these two scenarios to be considered
regardless of probability of the single failure was explicitly stated
in the NPRM for 14 CFR 25.981, as amended by amendment 25-102 (66 FR
23085, May 7, 2001). That NPRM stated, in pertinent part, that it would
also add a new paragraph (a)(3) to require that a safety analysis be
performed to demonstrate that the presence of an ignition source in the
fuel tank system could not result from ``any single failure, from any
single failure in combination with any latent failure condition not
shown to be extremely remote, or from any combination of failures not
shown to be extremely improbable.'' These new

requirements would define three scenarios that must be addressed in
order to show compliance with the proposed paragraph (a)(3). ``The
first scenario is that any single failure, regardless of the
probability of occurrence of the failure, must not cause an ignition
source. The second scenario is that any single failure, regardless of
the probability occurrence, in combination with any latent failure
condition not shown to be at least extremely remote (i.e., not shown to
be extremely remote or extremely improbable), must not cause an
ignition source. The third scenario is that any combination of failures
not shown to be extremely improbable must not cause an ignition
source.''
    The preamble to the final rule for amendment 25-102 made a nearly
identical statement, including the same uses of the phrase ``regardless
of probability.'' The FAA has determined that it is necessary to
proceed with issuance of this final rule as proposed. Further details
and a description of the FAA's risk assessment can be found in
responses to similar comments in a related SNPRM that addressed the
same unsafe condition for Model 757 airplanes, in Docket No. FAA-2012-
0187, and in the subsequently issued final rule, AD 2016-07-07,
amendment 39-18452 (81 FR 19472, April 5, 2016) (``AD 2016-07-07''). No
change to this AD was made in response to these comments.

Request To Withdraw NPRM: No Technical Justification

    FedEx requested that the FAA withdraw the NPRM, stating that the
proposed requirement has not been technically justified. FedEx stated
that 14 CFR 25.981, as amended by amendment 25-102; and SFAR 88 (in 14
CFR part 21); required the aircraft original equipment manufacturer
(OEM) to evaluate the Model 767 fuel system and components for
compliance with the new requirements. FedEx added that it understands
that Boeing and Goodrich Aerospace determined that the only FQIS
component that did not meet those requirements was the center tank's
densitometer. FedEx noted that AD 2010-06-10, Amendment 39-16234 (75 FR
15322, March 29, 2010) (``AD 2010-06-10''), was issued to install
support hardware, modify the wiring of the center wing tank FQIS
densitometer, and replace the hot short protector for the center tank.
FedEx added that Boeing and Goodrich did not determine a need for
additional barrier devices on the Model 767 FQIS.
    The FAA does not agree to withdraw the rule. The FAA notes that
FedEx's understanding of the results of Boeing's Model 767 FQIS SFAR 88
analysis is not correct. Boeing's analysis also identified the FQIS
latent-plus-one condition as non-compliant with 14 CFR 25.981(a)(3).
Consequently, the FAA has determined modifying the FQIS is necessary to
prevent development of an ignition source inside the center fuel tank
due to electrical fault conditions. The FAA has not changed this AD
regarding this issue.

Request To Withdraw NPRM: No New Data Since FTFR Rulemaking

    A4A/CAA and UPS requested that the FAA withdraw the NPRM based on a
lack of new data since the issuance of the FTFR rule (73 FR 42444, July
21, 2008). The commenters referred to the FTFR rule and decision to not
require FRM for all-cargo airplanes, and the FAA's intent to gather
additional data and consideration of further rulemaking if flammability
of these airplanes is excessive. UPS stated that since the FTFR rule,
no additional data has been publicly introduced that would support or
justify the applicability of this rulemaking to all-cargo aircraft. The
commenters also referred to the FAA's response to comments in the
preamble to the SNPRM for Docket No. FAA-2012 0187, which documented
the FAA's decision on applicability of FRM and cost estimates. The
commenters stated that the FAA response was misleading and not factual
since manufacturers did not begin detailed designs to address the
proposed unsafe condition until after the FTFR rule was published. The
commenters added that the FAA did not discuss other changes to the FQIS
system in the FTFR rule.
    The FAA disagrees with the commenters' request. The FAA notes that
the FTFR rule and FQIS ADs are two different issues with separate FAA
actions. The intent of the FTFR rule was to provide an order of
magnitude reduction in the rate of fuel tank explosions for the
airplanes affected by that rule through adding a new airworthiness
standard for the flammability of fuel tanks. The FAA notes that the
FTFR rule was never intended to be a replacement for the issuance of
ADs to address identified unsafe conditions. An unsafe condition due to
the identified FQIS latent-plus-single failure issue in high-
flammability fuel tanks was determined to exist during the SFAR 88 AD
Board held by the FAA in 2003 using the guidance in FAA Policy
Memorandum ANM100-2003-112-15 for high-flammability fuel tanks,
including the center fuel tank on Model 767-200, -300, -300F, and -
400ER series airplanes. That same issue was not considered to be an
unsafe condition in low-flammability wing fuel tanks based on that same
policy memorandum. The FAA has not changed this AD regarding this
issue.

Request To Withdraw NPRM: Insufficient Justification for AD

    Based on an assertion that the FAA did not sufficiently explain how
the unsafe condition justifies AD rulemaking, UPS requested that the
FAA withdraw the NPRM. UPS stated that the FTFR rule did not suggest
that any future modifications of FQIS systems had been considered. UPS
contended that all-cargo operators were surprised and prejudiced by
costly proposed FQIS modifications that are unsupported by both an
updated risk assessment and full cost/benefit analysis that consider
the pertinent facts. UPS alleged that the FAA did not fully explain or
justify its decision making for the NPRM, and concluded that the NPRM
is arbitrary and does not reflect properly reasoned agency action.
    The FAA disagrees with the commenter's request. A review of the
rulemaking record shows that the commenter's first assertion is not
correct. The FAA notes that Section III.K.5. of the preamble of the
FTFR rule states that ``the findings from the analysis required by SFAR
88 showed that most transport category airplanes with high-flammability
fuel tanks needed transient suppression units (TSUs) to prevent
electrical energy from airplane wiring from entering the fuel tanks in
the event of a latent failure in combination with a single failure.''
In addition, the NPRM for the FTFR rule states: ``As part of the safety
reviews of SFAR 88, we have identified other models that likewise would
need a transient suppression device.'' These statements indicate that
the FAA expects to take AD action on multiple airplane models to
address FQIS issues identified through the SFAR 88 analyses. The
preamble of the FTFR rule also states that the proposed FRM has the
potential to reduce the industry cost associated with those expected
ADs because the installation of an FRM likely would eliminate the need
to further address the FQIS issue through AD actions.
    The purpose of those statements was to note that there would be
some cost savings to industry resulting from the elimination of other
actions required to address an unsafe condition for the airplanes
affected by the proposed rules, and to point out that the FAA did not
take credit for those potential cost reductions in assessing the cost
of the FTFR rule because the costs were not

well understood at the time. That statement was not a commitment by the
FAA to forego issuing ADs if necessary to address an identified unsafe
condition on the airplanes but rather to not require the affected
airplanes to incorporate FRM. As noted previously, the NPRM for the
FTFR rule and the FTFR rule both made statements indicating that the
FAA expects to issue AD actions on multiple airplane models to address
FQIS issues identified through the SFAR 88 analyses. The FAA explained
the unsafe condition and the risk on anticipated flights with a pre-
existing latent failure condition in the NPRM to this final rule. The
FAA also provided an estimate of the costs associated with the proposed
AD in accordance with FAA rulemaking policy and the Administrative
Procedures Act. The FAA has not changed this AD regarding this issue.

Request To Withdraw NPRM: NPRM Arbitrary and Inconsistently Applied

    A4A/CAA and UPS requested that the FAA withdraw the NPRM. The
commenters noted that airplanes with FRM are not included in the
applicability, and the NPRM would therefore not fully address the
unsafe condition. The commenters added that the distinction between
high- and low-flammability exposure time fuel tanks as used in the NPRM
is arbitrary. The commenters stated that an arbitrary differentiation
of high- versus low-flammability as decisional criteria for the need
for corrective action does not take into account the actual probability
of the impact of the difference in flammability on the potential of
catastrophic failure. The commenters also stated that allowing the
proposed alternative actions for cargo airplanes does not fully address
the unsafe condition in the NPRM. The commenters referenced the FAA's
response to comments in AD 2016-07-07 regarding this issue. The
commenters summarized numerical analysis showing no significant
difference in risk between high- and low-flammability fuel tanks. The
commenters concluded that the FAA's risk analysis is arbitrary and an
unsafe condition does not exist.
    The FAA disagrees with the assertion that the NPRM is arbitrary and
inconsistent. The NPRM follows defined policy in FAA Policy Memorandum
ANM100-2003-112-15, and consistently applies the policy to several
airplane models with similar unsafe conditions, similar to AD 2016-07-
07. The FAA defined the difference between low- and high-flammability
exposure time fuel tanks based on recommendations from the Aviation
Rulemaking Advisory Committee Fuel Tank Harmonization Working Group
(FTHWG). The preamble to the final rule for amendment 25-102, which
amended 14 CFR 25.981, defined this difference as based upon comparison
of ``the safety record of center wing fuel tanks that, in certain
airplanes, are heated by equipment located under the tank, and unheated
fuel tanks located in the wing.'' The FTHWG concluded that the safety
record of fuel tanks located in the wings was adequate and that if the
same level could be achieved in center wing fuel tanks, the overall
safety objective would be achieved.
    In the response to comments in the preamble to the final rule for
AD 2016-07-07 referenced by the commenters, the FAA described why FRM
or alternative actions for cargo airplanes provide an acceptable level
of safety, even if they do not completely eliminate the non-compliance
with 14 CFR 25.981(a)(3).
    The fuel tank explosion history for turbojet/turbofan powered
transport airplanes fueled with kerosene type fuel, outside of
maintenance activity, has consisted of explosions of tanks that (1) are
not conventional aluminum wing tanks and (2) spend a considerable
amount of their operating time empty. The service history of
conventional aluminum wing tanks has been acceptable. The intent of the
difference in decision criteria in FAA Policy Memorandum ANM100-2003-
112-15 was intended to give credit for this satisfactory service
experience, and to differentiate between tanks with a level of
flammability similar to that of a conventional wing tank and those with
a significantly higher level of flammability.
    The numerical analysis provided by the commenters is inconsistent
with the fuel tank explosion service history. There are at least three
identifiable physics-based reasons for that inconsistency. First, low-
flammability tanks on most types of airplanes are main tanks that are
the last tanks used. During a large portion of their operating time,
the systems and structural features that have the potential to be
ignition sources in the event of a failure condition are covered with
liquid fuel, and an ignition source, if it occurs, is likely to be
submerged. When a potential ignition source in a main tank is
uncovered, it is likely to be later in the flight when the tank is cool
and no longer flammable. The commenters' analysis does not account for
this significant effect. Second, the numerical analysis used by the
commenters assumes that any given ignition source has a random
occurrence in time at the estimated probability, and that, in order for
an explosion to occur, that random occurrence of an ignition source
needs to coincide with the tank being in a flammable state. In fact,
many of the identified ignition threats do not simply occur briefly and
then go away. Instead, a fault occurs that, until it is discovered and
corrected, repeatedly creates an ignition source, and repeatedly tests
whether flammable conditions exist.
    Third, the flammability of low-flammability fuel tanks is typically
dependent on weather, and a low-flammability fuel tank may operate for
months without ever becoming flammable. This is not true of most high-
flammability fuel tanks, which typically have significant on-airplane
heat sources driving their temperature. This factor can mean that, on
some airplanes, an in-tank latent failure can occur and, after some
period of time, be detected and corrected without the low flammability
tank ever having flammable conditions. The numerical analysis provided
by the commenters does not account for these significant factors. The
difference in likelihood of a failure that results in repeated ignition
source events causing a tank explosion is not simply proportional to
difference in the fleet average flammability of the tank for the
reasons stated above. The FAA has not changed this AD regarding this
issue.

Request To Withdraw NPRM: Arbitrary and Inconsistent Wire Separation
Standards

    A4A/CAA and UPS requested that the FAA withdraw the NPRM based on a
lack of consistent design standards for FQIS wire separation. The
commenters assumed that the approved standard for the retrofit is a 2-
inch wire separation minimum, which the commenters considered arbitrary
and inconsistently applied. The commenters reported that the amount of
wiring capable of meeting that separation standard varies widely among
airplane models. A4A/CAA and UPS also acknowledged that other
separation methods were used in areas not meeting the 2-inch wire
separation requirement.
    The FAA does not agree with the commenters' request. The degree of
physical isolation of FQIS wiring from other wiring, whether provided
by physical distance or barrier methods, that is necessary to eliminate
the potential for hot shorts due to wiring faults is dependent on the
materials used, the wire securing methods, and the possible types of
wiring faults. The FAA relied on the manufacturer to assess the details
of the design and to propose the appropriate isolation

measures. While 2 inches of physical separation may appear to be an
arbitrary number, it was the distance proposed by the manufacturer as
appropriate for their design based on analysis of the design details.
The FAA has not changed this AD regarding this issue.

Request To Withdraw NPRM: Not Justified Based on Cost-Benefit Analysis

    FedEx noted that the proposed AD does not include a cost-benefit
analysis. FedEx added that in the NPRM for the FTFR rule, the FAA
stated that proposal would not extend to airplanes used in all-cargo
operations because the cost did not appear justified by the associated
benefits. FedEx acknowledged that the FAA's statement was meant for the
installation of the NGS. However, FedEx stated that it believes the
current proposed rule would provide cost-benefit results that are less
justifiable than the FTFR rule. FedEx stated that while the costs may
be comparable, the benefits associated with the FQIS modification will
be less. The FAA infers that FedEx is requesting that the proposed rule
be withdrawn because it cannot be shown to be cost beneficial.
    The FAA does not agree that the proposed AD should be withdrawn or
that a full cost-benefit analysis is required to justify AD action to
address the identified unsafe condition. In the NPRM to this AD, the
FAA provided the cost analysis that is required by FAA policy and the
Administrative Procedures Act. In the NPRM, the FAA described the basis
for the unsafe condition determination, noting that a significant
number of flights are anticipated to occur in a non-fail-safe
condition. Such flights would not meet the minimum level of safety
expectations for transport airplanes. The cost of the requirement in
the airworthiness standards to provide fail-safe design was justified
at the time of rulemaking for the associated regulatory standards. The
fact that a design is later discovered not to have met the regulatory
standard and is very expensive to correct should not and does not
prevent the FAA from requiring appropriate corrective action to restore
a design to the minimum acceptable level of safety defined in the
airworthiness standards for that product. The FAA has not changed this
AD regarding this issue.

Request To Withdraw NPRM: Inadequate Fleet Exposure and Cost Estimates

    Boeing requested that the FAA withdraw the NPRM. Boeing stated that
the fleet exposure for the affected fleet continues to decrease due to
aging airplanes and adequate wire separation design on Model 767
airplanes. Boeing added that the estimated costs in the NPRM do not
take into account the costs of compliance for passenger airplanes
without FRM installed.
    The FAA disagrees with the commenter's request. The FAA did not
base its unsafe condition determination on fleet risk but instead on
individual risk. This is discussed in detail in the response to
comments in the SNPRM for Docket No. FAA-2012-0187, under the heading
``Request To Withdraw NPRM (77 FR 12506, March 1, 2012): Unjustified by
Risk.'' Therefore, the age of the airplane and its current production
stoppage do not affect the determination that an unsafe condition still
exists on an individual airplane.
    The NPRM for this proposed rule did contain a cost estimate for
passenger airplanes that was based on the estimate provided by Boeing
for the Model 757 and Model 767 airplanes, which have an FQIS of
similar design. The FAA notes that Boeing asserted that the cost to
operators of modifying an airplane's FQIS to be fully compliant with
the airworthiness standards would be similar to the cost of installing
Boeing's NGS flammability reduction system. Based on that, Boeing
requested that the FAA agree to not require Boeing to develop service
information for a fully compliant FQIS modification. However, the FAA
used Boeing's estimate of the cost to modify the Model 757 and Model
767 FQIS to a fully part-25-compliant configuration to provide the
estimated costs in the NPRM, based on an assumption that the cost for
Model 747 airplanes would be similar. At the time, Boeing concurred
with this estimate. This is discussed in detail in the response to
comments in the SNPRM for Docket No. FAA-2012-0187. The FAA has not
changed this AD regarding this issue.

Request To Withdraw NPRM: Underestimated Parts Cost

    FedEx stated that the proposed rule underestimates costs for the
required actions. Specifically, FedEx noted that Boeing estimates the
part kit cost for installing NGS to be $440,000, not $200,000 as stated
in the proposed AD. FedEx stated that the NGS is a very expensive
system, which adds undue burden on operators. FedEx claimed that the
proposed rule is therefore unjustified.
    The FAA agrees to clarify. The FAA's cost estimate in the NPRM was
not for installation of NGS, but rather was for an FQIS modification to
bring the FQIS into compliance with the applicable regulations. The
estimated parts cost and work hours used were those supplied by Boeing
and Goodrich Aerospace for such a modification. However, if an operator
chooses to install an NGS in lieu of accomplishing the modification,
the FAA acknowledges the parts cost would likely be higher for that
operator. The FAA has not changed this AD regarding this issue.

Request To Require Cargo Airplane Option for All Airplanes

    Boeing requested that the NPRM be revised to make the alternative
actions for cargo airplanes specified in paragraph (h) of the proposed
AD applicable to all airplanes, including passenger airplanes with FRM
not installed due to differences in foreign regulations. In addition,
Boeing requested that the actions specified in paragraph (h) of the
proposed AD become the primary means of compliance for all airplanes,
not an alternative method of compliance for some airplanes.
    The FAA disagrees with the commenter's request. As discussed in the
comment response in the SNPRM for Docket No. FAA-2012-0187, under the
heading ``Requests To Withdraw NPRM (77 FR 12506, March 1, 2012) Based
on Applicability'' the FAA does not consider the alternative action for
cargo airplanes allowed by this AD to provide an adequate level of
safety for passenger airplanes. The FAA is willing to accept a higher
level of individual flight risk exposure for cargo flights that are not
fail-safe due to the absence of passengers and the resulting
significant reduction in occupant exposure on a cargo airplane versus a
passenger airplane, and due to relatively low estimated individual
flight risk that would exist on a cargo airplane after the corrective
actions are taken. The FAA has not changed this AD regarding this
issue.

Request To Change Compliance Time

    A4A/CAA, FedEx, Japan Airlines (JAL), and Air Transport
International requested that the FAA extend the compliance time for the
modifications specified in paragraphs (g) and (h)(2) of the proposed AD
to 72 months. A4A/CAA stated that the compliance time should match that
of AD 2016-07-07 because the unsafe condition and corrective actions
are similar. Air Transport International noted the longer compliance
time would provide additional time for passenger-to-freighter
conversions to incorporate a currently unreleased service bulletin into
any supplemental type certificate (STC). A4A/CAA stated that although

service information was not yet available, the compliance time should
align with major maintenance schedules, but should be not less than 72
months after service information is available.
    Conversely, NATCA recommended that the FAA reject requests for a
compliance time longer than 5 years as proposed in the NPRM. Assuming
final rule issuance in 2016, NATCA estimated that a 5-year compliance
time would result in required compliance by 2021--25 years after the
TWA Flight 800 fuel tank explosion that led to the requirements in SFAR
88, and 20 years after issuance of SFAR 88.
    The FAA agrees with the commenters' requests to extend the
compliance time, and disagrees with NATCA's request. The FAA received
similar requests to extend the compliance time from several commenters
regarding the NPRMs for the FQIS modification on other airplanes. The
FAA disagrees with establishing a compliance time based on issuance of
the service information that is not yet approved or available. The FAA
has determined that a 72-month compliance time is appropriate and will
provide operators adequate time to prepare for and perform the required
modifications without excessive disruption of operations. The FAA has
determined that the requested moderate increase in compliance time will
continue to provide an acceptable level of safety. The FAA has changed
paragraphs (g) and (h)(2) of this AD accordingly.

Request To Extend Repetitive BITE Check Interval

    Air Transport International and All Nippon Airways (ANA) requested
that paragraph (h)(1) of the proposed AD be revised to extend the
repetitive check interval for the BITE checks. Air Transport
International requested that the repetitive interval be extended to 750
flight hours to match the repetitive interval specified in AD 2016-07-
07. ANA noted that an interval of 750 flight hours will allow the check
to be done during A-check intervals.
    The FAA agrees to extend the repetitive check interval to 750
flight hours. The FAA intended to propose a 750 flight hour interval,
but inadvertently specified 650 flight hour intervals in the proposed
AD. The FAA has revised paragraph (h)(1) of this AD to specify
repetitive intervals of 750 flight hours.

Request To Clarify Actions in Paragraph (h)(1) of the Proposed AD

    ANA requested that the FAA clarify the actions specified in
paragraph (h)(1) of the proposed AD. ANA noted there are two actions
(record the existing fault code stored in the FQIS processor prior to
doing the BITE check of the FQIS and do a BITE check of the FQIS) that
must be done using Boeing Service Bulletin 767-28-0118, dated July 15,
2014. ANA stated Boeing Service Bulletin 767-28-0118, dated July 15,
2014, does not contain specific instructions to record existing fault
codes. ANA noted that recording existing fault codes can be done using
existing maintenance tasks. ANA asked if recording the existing fault
codes must be done using Boeing Service Bulletin 767-28-0118, dated
July 15, 2014, and if so, requested that Boeing Service Bulletin 767-
28-0118, dated July 15, 2014, be revised to address the AD action.
    The FAA agrees to clarify. Boeing Service Bulletin 767-28-0118,
dated July 15, 2014, contains notes in Parts 4 and 5 of the
Accomplishment Instructions stating that operators should record the
existing faults prior to initiating the BITE check of the processor.
However, those notes don't include specific procedures. Operators may
use accepted procedures, including existing maintenance tasks, to
comply with the requirements to record existing fault codes. No change
to this AD is necessary.

Request To Clarify Whether Certain Actions Can Be Done Without
Obtaining an Alternative Method of Compliance (AMOC)

    ABX AIR requested that the FAA clarify whether it can perform the
repetitive checks specified in paragraph (h)(1) of the proposed AD. ABX
AIR noted that it operates airplanes converted to a cargo configuration
using an STC, so its airplanes are not included in the effectivity of
Boeing Service Bulletin 767-28-0118, dated July 15, 2014. ABX AIR asked
if it could still do the repetitive checks in accordance with Boeing
Service Bulletin 767-28-0118, dated July 15, 2014, without obtaining an
AMOC.
    The FAA agrees to clarify. The FAA determined that the BITE check
procedures in the service bulletin are applicable to all Boeing 767
airplanes. Therefore, it is acceptable to use the procedures specified
in the service information even on airplanes that are not listed in the
effectivity of Boeing Service Bulletin 767-28-0118, dated July 15,
2014.

Request To Provide Dispensation for Airplanes To Be Retired

    British Airways (BA) requested that the proposed AD be revised to
provide dispensation for aircraft to be retired, which would not be
prohibitive for operators. BA stated that the only Boeing solution
available to comply with the proposed AD is to install an NGS. BA
further stated that NGS is not mandatory for operators outside of the
U.S. and is a high cost, high work-hour modification.
    The FAA infers that the commenter is requesting an extension of the
compliance time for airplanes that will be retired by a certain date or
for the AD to exclude those airplanes. The FAA notes that the commenter
did not propose a specific period of additional time for operation
without addressing the unsafe condition, and did not propose any
specific alternative corrective actions. The FAA's understanding is
that British Airways no longer operates Model 767 airplanes. The FAA
also notes that this AD does not require installing an NGS; this AD
requires an FQIS modification. If the commenter or another operator
wishes to make a specific proposal, they can submit that proposal using
the AMOC process specified in paragraph (j) of this AD. The FAA has not
changed this AD regarding this issue.

Request To State That an Exemption Is Required

    Boeing requested that paragraph (h) of the proposed AD be revised
to state that an exemption is required to accomplish the specified
actions. Boeing stated that the FAA has identified that the BITE
procedure and wire separation design changes specified in the proposed
AD are not sufficient for compliance to 14 CFR 25.981(a) at the FQIS
level. Boeing stated that an exemption is therefore needed prior to
approval of the related design change.
    The FAA agrees to clarify. The BITE check is not a type design
change or alteration, so no exemption from the airworthiness standards
is required for that action. The FAA design data approval of any
partial wire separation modification would require an exemption. That
exemption would be obtained by the party seeking approval of the
alteration data, and no further exemption would be required for the
party using that data to alter an aircraft. Obtaining such an exemption
would be part of the certification process for such a change, so the
FAA does not find it necessary to include such information in paragraph
(h) of this AD. In addition, some parties may choose to comply with the
AD using a design change that fully complies with the airworthiness
standards. The FAA also notes that the commenter appears to
misunderstand why an exemption is needed for the required modification.
The exemption is

needed because, even with the modification, the FQIS does not comply
with 14 CFR 25.901(c) and 14 CFR 25.981(a). The exemption does not
authorize evaluation of a partial system for compliance with the system
level requirement. The FAA has not changed this AD regarding this
issue.

Request To Clarify Certification Basis for Modification Requirements

    NATCA recommended that the FAA revise paragraph (g) of the proposed
AD to clearly state that the required FQIS design changes must comply
with the fail-safe requirements of 14 CFR 25.901(c), as amended by
amendment 25-46 (43 FR 50597, October 30, 1978); and 14 CFR 25.981(a)
and (b), as amended by amendment 25-102; NATCA added that these
provisions are required by SFAR 88.
    The FAA does not agree to change paragraph (g) of this AD. While
the FAA agrees that modifications to comply with paragraph (g) should
be required to comply with the referenced regulations, that requirement
already exists in 14 CFR part 21. No change to this AD is necessary.

Request To Require Modification on All Production Airplanes

    NATCA recommended that the FAA require designs that comply with 14
CFR 25.901(c) and 25.981(a)(3) on all newly produced transport
airplanes. NATCA stated that continuing to grant exemptions to 14 CFR
25.901(c), as amended by amendment 25-40 (42 FR 15042, March 17, 1977);
and 14 CFR 25.981(a)(3), as amended by amendment 25-102; has allowed
continued production of thousands of airplanes with this known unsafe
condition.
    The FAA disagrees with the commenter's request. The recommendation
to require production airplanes to fully comply with 14 CFR 25.901(c)
and 14 CFR 25.981(a)(3) is outside the scope of this rulemaking. The
FAA has implemented requirements for all large transport airplanes
produced after September 2010 to include flammability reduction methods
for tanks that would otherwise be high-flammability fuel tanks. Boeing
incorporated this change into the Model 767 series airplanes that are
still in production and the FAA has excluded those airplanes from the
applicability of this AD. The FAA has not changed this final rule
regarding this issue.

Request To Exclude Certain Airplanes

    United Airlines (UAL) requested that the FAA revise the proposed AD
to exclude airplanes that are affected by 14 CFR 121.1117. UAL noted
that the FRM required by 14 CFR 121.1117 will have been installed on
all affected airplanes in passenger configuration by December 26, 2018.
UAL suggested that the FAA either delete paragraph (g) of the proposed
AD or make paragraph (g) of the proposed AD applicable only to
airplanes in a cargo configuration that do not have an FRM installed
and non-U.S.-registered airplanes that do not have to comply with FRM
requirements.
    The FAA disagrees with the commenter's request. There are other
passenger-carrying airplanes operated under 14 CFR part 91 that are not
required to install FRM. (The requirement to install FRM on all
passenger-carrying airplanes operated by air carriers is in 14 CFR
121.1117.) The FAA notes that foreign air carriers may not have to
comply with that requirement or similar requirements of their own civil
aviation authority. EASA, for example, has chosen not to require FRM to
be retrofitted to in-service airplanes. The proposed AD is intended to
require any Model 767 series passenger airplane that does not have FRM,
regardless of the rules under which it is operated, to address the FQIS
latent-plus-one unsafe condition with a corrective action that fully
complies with the FAA airworthiness standards. This requirement
fulfills the FAA's International Civil Aviation Organization (ICAO)
obligation to address unsafe conditions on all of the aircraft
manufactured by the state of design, not just those aircraft whose
operation is under the jurisdiction of the state of design. The FAA has
not changed this AD regarding this issue.

Request To Provide Cost-Effective Method of Compliance

    BA and JAL requested that the FAA encourage Boeing to provide a
cost-effective method of compliance for passenger airplanes. JAL noted
that Boeing expects the NGS installation to be an AMOC for the proposed
AD. However, JAL and BA noted that the majority of non-FAA operators
are not required to retrofit the NGS system. The commenters requested
that the FAA encourage Boeing to develop an acceptable cost-effective
method of compliance that does not require installation of an NGS.
    The FAA agrees that the lack of service information for FQIS
modifications makes it difficult to assess the required work to modify
the FQIS, and acknowledges the high cost of NGS. However, the FAA
disagrees with the commenters' request. For passenger-carrying
airplanes, the cost per airplane of providing a modification of the
FQIS that fully complies with the airworthiness standards was estimated
by Boeing and their FQIS vendor (Goodrich) prior to the issuance of the
NPRM to be comparable to the cost of installing NGS. Based on that cost
estimate, Boeing proposed that they not be required to develop a fully
compliant FQIS modification for passenger airplanes because it would
not provide significant savings to operators and NGS would provide a
greater safety benefit. The FAA agreed. The FAA's understanding is that
Boeing's current position is the same, and that they do not plan to
develop a fully compliant FQIS modification for passenger airplanes to
address paragraph (g) of this AD. However, if service information is
developed, approved, and available in the future, operators may request
approval under the provisions of paragraph (j) of this AD to use
approved service instructions as an AMOC for the requirements of this
AD, or the FAA may approve the service information as a global AMOC for
this AD. In addition, Boeing has issued Service Bulletin 767-28-0122,
Revision 1, dated February 26, 2020, for all-cargo airplanes, and the
FAA has revised paragraph (h)(2) of this AD to specify that Boeing
Service Bulletin 767-28-0122, Revision 1, dated February 26, 2020, is
an acceptable method of compliance. This revision includes adding
paragraphs (h)(2)(i) and (ii) of this AD. The FAA has also added
paragraph (i) of this AD to provide credit for Boeing Service Bulletin
767-28-0122, dated October 11, 2016, and redesignated subsequent
paragraphs accordingly. The FAA has also revised the Estimated Costs
for Alternative Actions table in this final rule to include the
estimated costs for the wire separation modification specified in
Boeing Service Bulletin 767-28-0122, Revision 1, dated February 26,
2020, if operators choose to comply using that method.
    The FAA notes that this cost estimate is based on data provided in
Boeing Service Bulletin 767-28-0122, dated October 11, 2016, while the
cost estimate provided for a modification using methods approved in
accordance with the procedures specified in paragraph (h)(2)(i) of this
AD (paragraph (h)(2) of the proposed AD) is based on data provided by
the manufacturer for Model 757 and 767 airplanes. The FAA had
previously determined, as specified in the NPRM, that the work involved
for the cargo airplane wire separation modification would take 230
work-hours. Boeing has since provided an updated estimate of 74 work-
hours for the alternative modification for cargo airplanes. The FAA has
revised the cost

estimate for the modification accordingly in this final rule.

Request To Require Design Changes From Manufacturers

    NATCA recommended that the FAA follow the agency's compliance and
enforcement policy to require manufacturers to develop the necessary
design changes soon enough to support operators' ability to comply with
the proposed requirements. NATCA noted that SFAR 88 required
manufacturers to develop all design changes for unsafe conditions
identified by their SFAR 88 design reviews by December 2002, or within
an additional 18 months if the FAA granted an extension.
    The FAA acknowledges the commenter's concerns. However, any
enforcement action is outside the scope of this rulemaking. The FAA has
not changed this final rule regarding this issue.

Request To Address Unsafe Condition on All Fuel Tanks

    NATCA recommended that the FAA require design changes that
eliminate unsafe FQIS failure conditions on all fuel tanks on the
affected models, regardless of fuel tank location or the percentage of
time the fuel tank is flammable. NATCA referred to four fuel tank
explosions in low-flammability exposure time fuel tanks identified by
the FAA during FTFR rulemaking. NATCA stated that neither FRM nor
alternative actions for cargo airplanes (e.g., BITE checks (checks of
built-in test equipment) followed by applicable repairs before further
flight and modification of the center fuel tank FQIS wiring within 60
months) would bring the airplane into full regulatory compliance. NATCA
added that the combination of failures described in the NPRM meets the
criteria for ``known combinations'' of failures that require corrective
action in FAA Policy Memorandum ANM100-2003-112-15.
    The FAA disagrees with the commenter's request. The FAA has
determined that according to Policy Memorandum ANM100-2003-112-15, the
failure condition for the airplanes affected by this AD should not be
classified as a ``known combination.'' While the FQIS design
architecture is similar to that of the early Boeing Model 747
configuration that is suspected of contributing to the TWA Flight 800
fuel tank explosion, significant differences exist in the design of
FQIS components and wire installations between the affected The Boeing
Company models and the early Model 747 airplanes such that the intent
of the ``known combinations'' provision for low-flammability fuel tanks
in the policy memorandum is not applicable. Therefore, this AD affects
only the identified Boeing airplanes with high-flammability exposure
time fuel tanks, as specified in paragraph (c) of this AD. The FAA
provided a detailed response to similar comments in the preamble of the
final rule for AD 2016-07-07. The FAA has not changed this final rule
regarding this issue.

Clarification of Applicability

    The FAA has added paragraph (c)(3) to this AD to clarify that
airplanes equipped with an ignition mitigation means (IMM) approved by
the FAA as compliant with certain regulations are excluded from this
AD. The FAA intended for airplanes with compliant IMM to be excluded
from the actions required by this AD. The FAA has determined that the
installation of an approved IMM provides a level of risk reduction at
least as great as that provided by FRM and adequately addresses the
unsafe condition.

Clarification of BITE Check Compliance Time

    The FAA has revised paragraph (h)(1) of this AD to clarify the
compliance time for the BITE check relative to the requirement to
record the fault codes. The FAA recognized that operators might
interpret the proposed requirements for alternative actions for cargo
airplanes as allowing additional flights prior to performing the BITE
check after first recording the fault codes. The FAA intended for
operators to perform the BITE check immediately after recording the
fault codes to address both the fault codes that exist prior to
performing the BITE check and any new codes that are identified during
the BITE check.

Conclusion

    The FAA reviewed the relevant data, considered the comments
received, and determined that air safety and the public interest
require adopting this final rule with the changes described previously
and minor editorial changes. The FAA has determined that these minor
changes:
     Are consistent with the intent that was proposed in the
NPRM for addressing the unsafe condition; and
     Do not add any additional burden upon the public than was
already proposed in the NPRM.
    The FAA also determined that these changes will not increase the
economic burden on any operator or increase the scope of this final
rule.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Service Bulletin 767-28-0118, dated July
15, 2014. This service information describes procedures for a BITE
check of the FQIS.
    The FAA also reviewed Boeing Service Bulletin 767-28-0122, Revision
1, dated February 26, 2020. This service information describes
procedures for modifying the airplane by separating FQIS wiring that
runs between the FQIS processor and the center tank wing spar
penetrations from other airplane wiring and applicable corrective
actions (including correcting loop resistance and electrical bonding
resistance).
    This service information is reasonably available because the
interested parties have access to it through their normal course of
business or by the means identified in the ADDRESSES section.

Costs of Compliance

    The FAA estimates that this AD affects 261 airplanes of U.S.
registry. This estimate includes 255 cargo airplanes; 4 private,
business/corporate/executive, or government airplanes; and 2
experimental airplanes. The FAA estimates the following costs to comply
with this AD:

                                        Estimated Costs: Required Actions
----------------------------------------------------------------------------------------------------------------
                                                                                Cost per       Cost on U.S.
              Action                        Labor cost            Parts cost        product         operators
----------------------------------------------------------------------------------------------------------------
Modification......................  1,200 work-hours x $85           $200,000         $302,000      $78,822,000
                                     per hour = $102,000.
----------------------------------------------------------------------------------------------------------------

                                      Estimated Costs: Alternative Actions
----------------------------------------------------------------------------------------------------------------
              Action                        Labor cost                 Parts cost           Cost per  product
----------------------------------------------------------------------------------------------------------------
BITE check........................  18 work-hours x $85 per     $0.....................  $1,530 per check.
                                     hour = $1,530 per check..
Wire separation (using service      Up to 289 work-hours x $85  Up to $51,970..........  Up to $76,535.
 information).                       per hour = Up to $24,565.
Wire separation...................  74 work-hours x $85 per     $10,000................  $16,290.
                                     hour = $6,290.
----------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. Subtitle VII: Aviation Programs,
describes in more detail the scope of the Agency's authority.
    The FAA is issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701: General requirements.
Under that section, Congress charges the FAA with promoting safe flight
of civil aircraft in air commerce by prescribing regulations for
practices, methods, and procedures the Administrator finds necessary
for safety in air commerce. This regulation is within the scope of that
authority because it addresses an unsafe condition that is likely to
exist or develop on products identified in this rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order
13132. This AD will not have a substantial direct effect on the States,
on the relationship between the national government and the States, or
on the distribution of power and responsibilities among the various
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, and
    (3) Will not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.

Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness
directive (AD):

2020-18-16 The Boeing Company: Amendment 39-21237; Docket No. FAA-
2016-6141; Product Identifier 2015-NM-048-AD.

(a) Effective Date

    This AD is effective November 10, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 767-200, -300, -
300F, and -400ER series airplanes, certificated in any category,
excluding airplanes identified in paragraphs (c)(1) through (3) of
this AD.
    (1) Airplanes on which the center auxiliary tank consists only
of the spaces between the side of body rib 0 and rib 3 of the left
and right wings (i.e., the wing center structural box is a dry bay
and is not part of the fuel tank).
    (2) Airplanes equipped with a flammability reduction means (FRM)
approved by the FAA as compliant with the fuel tank flammability
reduction (FTFR) requirements of 14 CFR 25.981(b) or 26.33(c)(1).
    (3) Airplanes equipped with an ignition mitigation means (IMM)
approved by the FAA as compliant with the FTFR requirements of 14
CFR 25.981(c) or 26.33(c)(2).

(d) Subject

    Air Transport Association (ATA) of America Code 28, Fuel.

(e) Unsafe Condition

    This AD was prompted by the FAA's analysis of the Model 767 fuel
system reviews conducted by the manufacturer. The FAA is issuing
this AD to prevent ignition sources inside the center fuel tank,
which, in combination with flammable fuel vapors, could result in a
fuel tank explosion and consequent loss of the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified,
unless already done.

(g) Modification

    Within 72 months after the effective date of this AD, modify the
fuel quantity indicating system (FQIS) to prevent development of an
ignition source inside the center fuel tank due to electrical fault
conditions, using a method approved in accordance with the
procedures specified in paragraph (j) of this AD.

(h) Alternative Actions for Cargo Airplanes

    For airplanes used exclusively for cargo operations: As an
alternative to the requirements of paragraph (g) of this AD, do the
actions specified in paragraphs (h)(1) and (2) of this AD. To
exercise this option, operators must perform the first inspection
required under paragraph (h)(1) of this AD within 6 months after the
effective date of this AD. To exercise this option for airplanes
returned to service after conversion of the airplane from a
passenger configuration to an all-cargo configuration more than 6
months after the effective date of this AD, operators must perform
the first inspection required under paragraph (h)(1) of this AD
prior to further flight after the conversion.
    (1) Within 6 months after the effective date of this AD, record
the existing fault codes stored in the FQIS processor and before
further flight thereafter do a BITE check (check of built-in test
equipment) of the FQIS, in accordance with the Accomplishment
Instructions of Boeing Service Bulletin 767-28-0118, dated July 15,
2014. If any nondispatchable fault code is recorded prior to the
BITE check or as a result of the BITE check, before further flight,
do all applicable repairs and repeat the BITE check until a
successful test is performed with no nondispatchable faults found,
in accordance with Boeing Service Bulletin 767-28-0118, dated July
15, 2014. Repeat these actions thereafter at intervals not to exceed
750 flight hours. Modification as specified in paragraph (h)(2) of
this AD does not terminate the repetitive BITE check requirement of
this paragraph.
    (2) Within 72 months after the effective date of this AD, do the
actions specified in paragraph (h)(2)(i) or (ii) of this AD.
    (i) Modify the airplane by separating FQIS wiring that runs
between the FQIS processor and the center tank wing spar
penetrations, including any circuits that might pass through a main
fuel tank, from other airplane wiring that is not intrinsically safe
using methods approved in accordance with the procedures specified
in paragraph (j) of this AD.
    (ii) Modify the airplane by separating FQIS wiring that runs
between the FQIS processor and the center tank wing spar
penetrations,

including any circuits that might pass through a main fuel tank,
from other airplane wiring that is not intrinsically safe, and do
all applicable corrective actions, in accordance with the
Accomplishment Instructions of Boeing Service Bulletin 767-28-0122,
Revision 1, dated February 26, 2020. Do all applicable corrective
actions before further flight.

(i) Credit for Previous Actions

    This paragraph provides credit for the actions specified in
paragraph (h)(2)(ii) of this AD, if those actions were performed
before the effective date of this AD using Boeing Service Bulletin
767-28-0122, dated October 11, 2016.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle ACO Branch, FAA, has the authority to
approve AMOCs for this AD, if requested using the procedures found
in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request
to your principal inspector or local Flight Standards District
Office, as appropriate. If sending information directly to the
manager of the certification office, send it to the attention of the
person identified in paragraph (k)(1) of this AD. Information may be
emailed to<EMAIL_ADDRESS>    (2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the local flight standards district office/certificate holding
district office.
    (3) An AMOC that provides an acceptable level of safety may be
used for any repair, modification, or alteration required by this AD
if it is approved by The Boeing Company Organization Designation
Authorization (ODA) that has been authorized by the Manager, Seattle
ACO Branch, FAA, to make those findings. To be approved, the repair
method, modification deviation, or alteration deviation must meet
the certification basis of the airplane, and the approval must
specifically refer to this AD.
    (4) For service information that contains steps that are labeled
as Required for Compliance (RC), the provisions of paragraphs
(j)(4)(i) and (ii) apply.
    (i) The steps labeled as RC, including substeps under an RC step
and any figures identified in an RC step, must be done to comply
with the AD. An AMOC is required for any deviations to RC steps,
including substeps and identified figures.
    (ii) Steps not labeled as RC may be deviated from using accepted
methods in accordance with the operator's maintenance or inspection
program without obtaining approval of an AMOC, provided the RC
steps, including substeps and identified figures, can still be done
as specified, and the airplane can be put back in an airworthy
condition.

(k) Related Information

    (1) For more information about this AD, contact Jon Regimbal,
Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch,
2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-
3557; email<EMAIL_ADDRESS>    (2) Service information identified in this AD that is not
incorporated by reference is available at the addresses specified in
paragraphs (l)(3) and (4) of this AD.

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the
incorporation by reference (IBR) of the service information listed
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing Service Bulletin 767-28-0118, dated July 15, 2014.
    (ii) Boeing Service Bulletin 767-28-0122, Revision 1, dated
February 26, 2020.
    (3) For service information identified in this AD, contact
Boeing Commercial Airplanes, Attention: Contractual & Data Services
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-
5600; telephone<PHONE_NUMBER>; internet https://www.myboeingfleet.com.
    (4) You may view this service information at the FAA,
Airworthiness Products Section, Operational Safety Branch, 2200
South 216th St., Des Moines, WA. For information on the availability
of this material at the FAA, call<PHONE_NUMBER>.
    (5) You may view this service information that is incorporated
by reference at the National Archives and Records Administration
(NARA). For information on the availability of this material at
NARA, email<EMAIL_ADDRESS>or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on August 26, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification
Service.
[FR Doc. 2020-21997 Filed 10-5-20; 8:45 am]
BILLING CODE 4910-13-P