AD 2013-13-09

We are adopting a new airworthiness directive (AD) for certain Learjet Inc. Model 60 airplanes. 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. This AD requires 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 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.

Final rule.

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):

2013-13-09 Learjet Inc.: Amendment 39-17497; Docket No. FAA-2013- 0214; Directorate Identifier 2012-NM-152-AD.

(a) Effective Date

This AD is effective August 6, 2013.

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(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 60-32-33, 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 60-57-7, 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 60-78-7, 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

For more information about this AD, contact Don Ristow, Aerospace Engineer, Mechanical Systems and PropulsionBranch, ACE- 116W, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, KS 67209; phone: 316-946- 4120; fax: 316-946-4107; email: donald.ristow@faa.gov.

(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) Bombardier Service Bulletin 60-32-33, dated July 23, 2012.
(ii) Bombardier Service Bulletin 60-57-7, dated July 23, 2012.
(iii) Bombardier Service Bulletin 60-78-7, Revision 2, dated May 1, 2006.
(3) For service information identified in this AD, contact Learjet, Inc., One Learjet Way, Wichita, KS 67209-2942; telephone 316-946-2000; fax 316-946-2220; email ac.ict@aero.bombardier.com; Internet http://www.bombardier.com.
(4) You may view this service information at FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221.
(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, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. The NPRM published in the Federal Register on March 27, 2013 (78 FR 18531). The NPRM proposed to 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

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interface box, and modifying the wiring for the new thrust reverser interface box.

Comments

We gave the public the opportunity to participate in developing this AD. We have considered the comment received. The National Transportation Safety Board supported the NPRM (78 FR 18531, March 27, 2013).

Conclusion

We reviewed the relevant data, considered the comment received, and determined that air safety and the public interest require adopting the AD as proposed except for minor editorial changes. We have determined that these minor changes:
Are consistent with the intent that was proposed in the NPRM (78 FR 18531, March 27, 2013) for correcting the unsafe condition; and
Do not add any additional burden upon the public than was already proposed in the NPRM (78 FR 18531, March 27, 2013).Interim Action

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

Estimated Costs --------------------------------------------------------------------------------------------------------------------------------------------------------
Action Labor cost Parts cost Cost per product Cost on U.S. operators -------------------------------------------------------------------------------------------------------------------------------------------------------- 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; and routing and securing
anti-skid wheel and squat switch
electrical wire harnesses to MLG
strut assembly (Bombardier Service
Bulletin 60[dash]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; and installation of aft
electricalcover and strap, and flat
landing light lamp (Bombardier
Service Bulletin 60-57-7, 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 serial
numbers 60[dash]002 through 60-276
(Bombardier Service Bulletin 60-78-7,
Revision 2, dated May 1, 2006) (132
U.S. airplanes). --------------------------------------------------------------------------------------------------------------------------------------------------------

According to the manufacturer, some of the costs of this 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

This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on therelationship 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) Is not a ``significant rule'' under 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.