AD 2011-04-08

We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires a general visual inspection for damage of wiring (including chafing, pinched wires, and exposed wires) and correct routing of wires in the left and right circuit breaker panels, and related investigative and corrective actions if necessary. This AD results from reports of wire damage on the pilot and copilot circuit breaker panels caused by a short circuit between chafed wiring and the circuit breaker panel forward mounting bracket. We are issuing this AD to detect and correct damaged or misrouted wires, which could result in a short circuit and the loss of systems associated with the wiring (including fire suppression function for one engine and essential avionics systems).

Final rule.

2011-04-08 Learjet Inc.: Amendment 39-16608; Docket No. FAA-2010- 0951; Directorate Identifier 2010-NM-107-AD.

Effective Date

(a) This AD is effective March 31, 2011.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Learjet Inc. Model 45 airplanes, certificated in any category; having serial numbers identified in paragraphs (c)(1) and (c)(2) of this AD.
(1) Serial numbers 45-2001 through 45-2114 inclusive, 45-2116 through 45-2120 inclusive, 45-2122, 45-2125, and 45-2126.
(2) Serial numbers 45-005 through 45-380 inclusive, 45-382 through 45-391 inclusive, 45-393 through 45-396 inclusive, 45-398, 45-400, 45-401, and 45-403.

Subject

(d) Air Transport Association (ATA) of America Code 24: Electrical power.

Unsafe Condition

(e) This AD results from reports of wire damage on the pilot and copilot circuit breaker panels caused by a short circuit between chafed wiring and the circuit breaker panel forward mounting bracket. The Federal Aviation Administration is issuing this AD to detect and correct damaged or misrouted wires, which could result in a short circuit and the loss of systems associated with the wiring (including fire suppression function for one engine and essential avionics systems).

Compliance

(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Inspection and Corrective Action

(g) Within 50 flight hours after the effective date of this AD: Do a general visual inspection for damage of wiring and correct routing of wires in the left and right circuit breaker panels, and all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A40-24-11, dated November 16, 2009; or Bombardier Alert Service Bulletin A45-24-16, dated November 16, 2009; as applicable; except if arcing damageis found on the forward mounting bracket of the circuit breaker panel, before further flight, repair in accordance with a method approved by the Manager, Wichita Aircraft Certification Office, FAA. Do all applicable related investigative and corrective actions before further flight.

Note 1: For the purposes of this AD, a general visual inspection is: ``A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.''

Alternative Methods of Compliance (AMOCs)

(h)(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. Send information to ATTN: Jose Flores, Aerospace Engineer, Electrical Systems and Avionics, ACE-119W, FAA, Wichita Aircraft Certification Office (ACO), 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone 316-946-4133; fax 316-946-4107.
(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.

Related Information

(i) For more information about this AD, contact Jose Flores, Aerospace Engineer, Electrical Systems and Avionics, ACE-119W, FAA, Wichita Aircraft Certification Office (ACO), 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone 316- 946-4133; fax 316-946-4107.

Material Incorporated by Reference

(j) You must use Bombardier Alert Service Bulletin A40-24-11, dated November 16, 2009; or Bombardier Alert Service Bulletin A45- 24-16, dated November 16, 2009; as applicable; to do the actions required by this AD, unless the AD specifies otherwise.
(1) The Director of the Federal Register approved the incorporation by reference of Bombardier Alert Service Bulletin A40- 24-11, dated November 16, 2009; and Bombardier Alert Service Bulletin A45-24-16, dated November 16, 2009; under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) For service information identified in this AD, contact Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942; telephone 316-946-2000; fax 316-946-2220; e-mail ac.ict@aero.bombardier.com; Internet http://www.bombardier.com.
(3) You may review copies of the service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221.
(4) You may also review copies of the service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at an NARA facility, call 202-741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to the specified products. That NPRM was published in the Federal Register on October 1, 2010 (75 FR 60667). That NPRM proposed to require a general visual inspection for damage of wiring (including chafing, pinched wires, and exposed wires) and correct routing of wires in the left and right circuit breaker panels, and related investigative and corrective actions if necessary.

Comments

We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal and the FAA's response to each comment.

Request To Revise Unsafe Condition

Learjet requested that we revise the unsafe condition, as stated in paragraph (e) of the NPRM, to ``This AD results from reports of wire damage on the pilot and copilot circuit breaker panels causedby a short circuit between chafed wiring and the circuit breaker panel forward mounting bracket'' instead of ``This AD results from reports of wire damage on the pilot and copilot circuit breaker panels caused by a short circuit between chafed wires.''
We agree with the commenter's request. We have revised the language in the SUMMARY section and paragraph (e) of this AD accordingly.

Request To Revise Paragraph (g) of the NPRM

Learjet requested that we revise paragraph (g) of the NPRM to ``except if arcing damage is found on the forward mounting bracket of the circuit breaker panel'' instead of ``except if arcing damage is found on the mounting brackets of the forward circuit breaker panel.''
We agree with the request provided by the commenter. We have revised paragraph (g) of this AD accordingly.

Conclusion

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD with thechanges described previously.
We also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD.

Costs of Compliance

We estimate that this AD affects 339 airplanes of U.S. registry. We also estimate that it would take about 1 work-hour per product to comply with this AD. The average labor rate is $85 per work-hour. Based on these figures, we estimate the cost of this AD to the U.S. operators to be $28,815, or $85 per product.

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 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) Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979),

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(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.

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):