[Federal Register Volume 78, Number 59 (Wednesday, March 27, 2013)]
[Proposed Rules]
[Pages 18531-18533]
[FR Doc No: 2013-07034]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2013-0214; Directorate Identifier 2012-NM-152-AD]
RIN 2120-AA64

Airworthiness Directives; Learjet Inc. Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for
certain Learjet Inc. Model 60 airplanes. This proposed AD was prompted
by a report of a high-speed rejected takeoff caused by all four main
landing gear (MLG) tires blowing out during the takeoff roll. This
proposed AD would require installing new rigid hydraulic tube
assemblies to the MLG struts, installing a new MLG squat switch
bracket, modifying the MLG squat switch wire harness, modifying the MLG
anti-skid wheel transducer electrical wire harnesses, routing and
securing the anti-skid wheel and squat switch electrical wire harnesses
to the MLG strut assembly; installing outboard bracket assemblies,
anti-skid shield, forward electrical cover on the forward stiffener,
upper and lower inboard bracket assemblies, and clamps that support the
electrical wire harness; modifying the aft stiffener for the new
electrical wire harness support; installing the aft electrical cover
and strap on the aft stiffener; installing a new flat landing light
lamp if necessary; and, for certain airplanes; installing a new wheel
speed detect box assembly, nutplates, and brackets and a new thrust
reverser interface box, and modifying the wiring for the new thrust
reverser interface box. We are proposing this AD to prevent failure of
the braking system or adverse operation of the spoiler and thrust
reverser system due to external damage, particularly from tire failure,
which could result in loss of control of the airplane.

DATES: We must receive comments on this proposed AD by May 13, 2013.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax:<PHONE_NUMBER>.
     Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact
Learjet, Inc., One Learjet Way, Wichita, KS 67209-2942; telephone 316-
946-2000; fax<PHONE_NUMBER>; email<EMAIL_ADDRESS>Internet
http://www.bombardier.com. You may review copies of the referenced
service information at the FAA, Transport Airplane Directorate, 1601
Lind Avenue SW., Renton, WA. For information on the availability of
this material at the FAA, call<PHONE_NUMBER>.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this proposed AD, the regulatory
evaluation, any comments received, and other information. The street
address for the Docket Office (phone:<PHONE_NUMBER>) is in the ADDRESSES
section. Comments will be available in the AD docket shortly after
receipt.

FOR FURTHER INFORMATION CONTACT: Don Ristow, Aerospace Engineer,
Mechanical Systems and Propulsion Branch, ACE-116W, FAA, Wichita
Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-
Continent Airport, Wichita, KS 67209; phone:<PHONE_NUMBER>; fax: 316-
946-4107; email<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under the ADDRESSES section. Include ``Docket No. FAA-2013-0214;
Directorate Identifier 2012-NM-152-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this proposed AD. We
will consider all comments received by the closing date and may amend
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.

Discussion

    We received a report of a high-speed rejected takeoff that occurred
when all four MLG tires blew out during the takeoff roll. The tires
blew out due to internal heat damage consistent with under-inflation,
overloading, or a combination of both. Subsequently, damage from tires
could cause damage to various components, including the MLG squat
switches, brake hydraulic tubes, wheel speed sensor wiring, and anti-
skid components. In the event of damage to the squat switch wiring,
thrust reverser operation can be affected adversely. This condition, if
not corrected, could result in failure of the braking system and
adverse operation of the spoiler and thrust reverser system, which
could result in loss of control of the airplane.

Relevant Service Information

    We reviewed Bombardier Service Bulletin SB60-32-33, dated July 23,
2012. The service bulletin describes procedures for installing new
rigid hydraulic tube assemblies to the MLG struts; installing a new MLG
squat switch bracket; modifying the MLG squat switch wire harness;
modifying the MLG anti-skid wheel transducer electrical wire harnesses;
and routing and securing the anti-skid wheel and squat switch
electrical wire harnesses to the MLG strut assembly.
    We reviewed Bombardier Service Bulletin SB60-57-7, dated July 23,
2012. This service bulletin describes procedures for installing
outboard bracket assemblies, anti-skid shield, forward electrical cover
on the forward stiffener, upper and lower inboard bracket assemblies,
and clamps that support the electrical wire harness; modifying the aft
stiffener for the new electrical wire harness support; installing the
aft electrical cover and strap on the aft stiffener; and installing a
new flat landing light lamp if necessary.
    We reviewed Bombardier Service Bulletin SB60-78-7, Revision 2,
dated May 1, 2006. For certain airplanes, this service bulletin
describes procedures for installing a new wheel speed detect box

assembly, nutplates, and brackets and a new thrust reverser interface
box, and modifying the wiring for the new thrust reverser interface
box.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

    This proposed AD would require accomplishing the actions specified
in the service information described previously.

Differences Between Proposed Rule and Service Bulletins

    Although Bombardier Service Bulletins SB60-32-33 and SB60-57-7,
both dated July 23, 2012, recommend accomplishing the modification and
installation within 600 flight hours or 24 months, whichever occurs
first, this proposed AD would require compliance within 600 flight
hours or 12 months, whichever occurs first. In developing an
appropriate compliance time for this AD, we considered not only the
manufacturer's recommendation, but the degree of urgency associated
with addressing the subject unsafe condition, the average utilization
of the affected fleet, and the time necessary to perform the
modifications. In light of all of these factors, we find a compliance
time of within 600 flight hours or 12 months, whichever occurs first,
for completing the required actions to be warranted, in that it
represents an appropriate interval of time for affected airplanes to
continue to operate without compromising safety. This difference has
been coordinated with the manufacturer.

Related Rulemaking

    On April 1, 2010, we issued AD 2010-11-11, Amendment 39-16316 (75
FR 32255, June 8, 2010), applicable to Learjet Inc. Model 60 airplanes,
serial number 60-002 through 60-369 inclusive. That AD currently
requires revising the Tire-Servicing section of the airplane
maintenance manual and revising the Tires Limitation section of the
airplane flight manual to incorporate revised procedures for servicing
tires and checking for proper tire inflation. That AD was prompted by a
report of the MLG tires blowing out during a takeoff roll. The actions
required by that AD are intended to prevent tire failure, which could
result in failures of the braking and thrust reverser systems; and in a
critical phase of operation such as takeoff, loss of airplane control
could result.
    Since issuance of AD 2010-11-11, Amendment 39-16316 (75 FR 32255,
June 8, 2010), the FAA has determined that the tire pressure check can
be terminated by accomplishing the actions specified in this proposed
AD.

Interim Action

    We consider this proposed AD the second of three ADs that are
related to each other, and collectively address unsafe conditions that
might result from damage to critical components on the landing gear or
in the wheel well that affect the braking, spoiler, and thrust reverser
systems. The manufacturer is currently developing a final modification
for the thrust reverser. Once the new thrust reverser modification is
developed, approved, and available, we might consider additional
rulemaking.

Costs of Compliance

    We estimate that this proposed AD affects 275 airplanes of U.S.
registry.
    We estimate the following costs to comply with this proposed AD:

                                                                     Estimated Costs
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                Action                          Labor cost           Parts cost             Cost per product                Cost on U.S.  operators
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Installation of rigid hydraulic tube    Up to 53 work-hours x $85          $7,093  Up to $11,598.....................  Up to $3,189,450.
 assemblies and MLG squat switch         per hour = $4,505.
 bracket; modification of MLG squat
 switch wire harness and MLG anti-skid
 wheel transducer electrical wire
 harnesses; routing and securing anti-
 skid wheel and squat switch
 electrical wire harnesses to MLG
 strut assembly (Bombardier Service
 Bulletin SB60-32-33, dated July 23,
 2012).
Installation of outboard bracket        Up to 25 work-hours x $85          17,960  Up to $20,085.....................  Up to $5,523,375.
 assemblies, anti-skid shield, forward   per hour = $2,125.
 electrical cover, upper and lower
 inboard bracket assemblies, and
 clamps; modification of aft
 stiffener; installation of aft
 electrical cover and strap, and flat
 landing light lamp (Bombardier
 Service Bulletin SB60-57-7, dated
 July 23, 2012).
Installation of wheel speed detect box  Up to 65 work-hours x $85           1,154  $6,679............................  Up to $881,628.
 assembly, nutplates brackets and        per hour = $5,525.
 thrust reverser interface box; and
 modification of wiring for S/Ns 60-
 002 through 60-276 (Bombardier
 Service Bulletin SB60-78-7, Revision
 2, dated May 1, 2006) (132 U.S.
 airplanes).
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    According to the manufacturer, some of the costs of this proposed
AD may be covered under warranty, thereby reducing the cost impact on
affected individuals. We do not control warranty coverage for affected
individuals. As a result, we have included all costs in our cost
estimate.

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.
    We are 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

    We determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 this proposed
regulation:
    (1) Is not a ``significant regulatory action'' under Executive
Order 12866,
    (2) Is not a ``significant rule'' under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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):

Learjet Inc.: Docket No. FAA-2013-0214; Directorate Identifier 2012-
NM-152-AD.

(a) Comments Due Date

    We must receive comments by May 13, 2013.

(b) Affected ADs

    Certain requirements of this AD affect certain requirements of
AD 2010-11-11, Amendment 39-16316 (75 FR 32255, June 8, 2010).

(c) Applicability

    This AD applies to Learjet Inc. Model 60 airplanes, certificated
in any category, serial numbers 60-001 through 60-413 inclusive.

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association
(ATA) of America Code 32, Landing gear; 57, Wings; 78, Engine
exhaust.

(e) Unsafe Condition

    This AD was prompted by a report of a high-speed rejected
takeoff caused by all four main landing gear (MLG) tires blowing out
during the takeoff roll. We are issuing this AD to prevent failure
of the braking system or adverse operation of the spoiler and thrust
reverser system due to external damage, particularly from tire
failure, which could result in loss of control of the airplane.

(f) Compliance

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

(g) Modification and Installation

    Within 600 flight hours or 12 months after the effective date of
this AD, whichever occurs first: Do the actions required by
paragraphs (g)(1), (g)(2), and (g)(3) of this AD, as applicable.
    (1) For all airplanes: Install new rigid hydraulic tube
assemblies to the MLG struts, install a new MLG squat switch bracket
and modify the MLG squat switch wire harness, modify the MLG anti-
skid wheel transducer electrical wire harnesses, and route and
secure the anti-skid wheel and squat switch electrical wire
harnesses to the MLG strut assembly; in accordance with the
Accomplishment Instructions of Bombardier Service Bulletin SB60-32-
33, dated July 23, 2012.
    (2) For all airplanes: Install outboard bracket assemblies,
anti-skid shield, forward electrical cover on the forward stiffener,
upper and lower inboard bracket assemblies, and clamps that support
the electrical wire harness; modify the aft stiffener for the new
electrical wire harness support; install the aft electrical cover
and strap on the aft stiffener; and install a new flat landing light
lamp, as applicable; in accordance with the Accomplishment
Instructions of Bombardier Service Bulletin SB60-57-7, dated July
23, 2012.
    (3) For airplanes having serial numbers 60-002 through 60-276
inclusive: Install a new wheel speed detect box assembly, nutplates,
brackets, and interface box; and modify the wiring for the new
thrust reverser interface box, in accordance with the Accomplishment
Instructions of Bombardier Service Bulletin SB60-78-7, Revision 2,
dated May 1, 2006.

(h) Terminating Action for AD 2010-11-11, Amendment 39-16316 (75 FR
32255, June 8, 2010)

    After accomplishing the actions required by paragraph (g) of
this AD, the requirement in paragraph (h) of AD 2010-11-11,
Amendment 39-16316 (75 FR 32255, June 8, 2010), to check the nose
and main tire pressures before 96 hours prior to takeoff, is
terminated. All provisions of paragraphs (g) and (h) of AD 2010-11-
11 that are not specifically referenced by this paragraph remain
fully applicable and must be complied with.

(i) Credit for Previous Actions

    This paragraph provides credit for the corresponding actions
specified in paragraph (g)(3) of this AD, if those actions were
performed before the effective date of this AD using Bombardier
Service Bulletin SB60-78-7, dated February 21, 2005; or Revision 1,
dated June 30, 2005; which are not incorporated by reference in this
AD.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Wichita Aircraft Certification Office (ACO),
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 ACO, send it to the
attention of the person identified in the Related Information
section of this AD.
    (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.

(k) Related Information

    (1) For more information about this AD, contact Don Ristow,
Aerospace Engineer, Mechanical Systems and Propulsion Branch, ACE-
116W, FAA, Wichita Aircraft Certification Office, 1801 Airport Road,
Room 100, Mid-Continent Airport, Wichita, KS 67209; phone: 316-946-
4120; fax:<PHONE_NUMBER>; email<EMAIL_ADDRESS>    (2) For service information identified in this AD, contact
Learjet, Inc., One Learjet Way, Wichita, KS 67209-2942; telephone
316-946-2000; fax<PHONE_NUMBER>; email<EMAIL_ADDRESS>
Internet http://www.bombardier.com. You may review copies of the
referenced service information at the FAA, Transport Airplane
Directorate, 1601 Lind Avenue SW., Renton, WA. For information on
the availability of this material at the FAA, call<PHONE_NUMBER>.

    Issued in Renton, Washington, on March 20, 2013.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2013-07034 Filed 3-26-13; 8:45 am]
BILLING CODE 4910-13-P