SUPPLEMENTARY INFORMATION:

Discussion

We received a report of a cabin fire in the left-hand upper cabin fuselage above the aft cabin window at frame 23 on a Learjet Model 55 airplane. If installed incorrectly, the power lead terminals of the lavatory light assembly have the potential to chafe against the oxygen line, causing deterioration of the insulation on the light assembly wiring. This condition, if not corrected, could result in contact between the electrical terminals of the light assembly and an adjacent oxygen supply line, and consequent short circuit or fire hazard.

Relevant Service Information

We reviewed Bombardier Alert Service Bulletin A55-25-7, dated December 17, 2008. The alert service bulletin describes procedures for an inspection of the installation of the forward light assembly in the aft lavatory to determine the location of the terminal connector (as shown in Figure 1, detail A of the alert service bulletin); an inspection for damage of the light assembly terminals, wires, and oxygen line; an inspection to determine if the cable nipple is installed over the light assembly terminal; and corrective actions if necessary. The corrective actions include turning the light assembly to locate the terminal connector in the forward position; replacing damaged light assembly terminals, wires, and oxygen line; and installing a new cable nipple. The alert service bulletin also describes procedures for installing a clamp to the forward side of the frame to maintain a positive distance between the light assembly and oxygen line.

FAA's Determination and Requirements of This AD

We are issuing 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(se) same type design(s). This AD requires accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the AD and the Service Information.”

Differences Between the AD and the Service Information

Operators should note that, although the Accomplishment Instructions of the Bombardier Alert Service Bulletin A55-25-7, dated December 17, 2008, describes procedures for submitting information to the manufacturer, this AD does not require that action.

Bombardier Alert Service Bulletin A55-25-7, dated December 17, 2008, refers only to doing “inspections.” We have determined that the procedures in the alert service bulletin should be described as “general visual inspections.” Note 1 has been included in this AD to define this type of inspection.

FAA's Justification and Determination of the Effective Date

This condition has the potential to compromise the integrity of the oxygen line due to the chafing between the light assembly terminals and oxygen line and has the potential to become an oxygen-fueled ignition source. Because of our requirement to promote safe flight of civil aircraft and thus the critical need to ensure the risk of fire is mitigated by proper installation of the forward light assembly in the aft lavatory and proper positive distance maintained between the oxygen line and light assembly, and the short compliance time involved with this action, this AD must be issued immediately.

Because an unsafe condition exists that requires the immediate adoption of this AD, we find that notice and opportunity for prior public comment hereon are impracticable and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited

This AD is a final rule that involves requirements affecting flight safety, and we did not provide you with notice and an opportunity to provide your comments before it becomes effective. However, we invite you to send any written data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2009-0054; Directorate Identifier 2008-NM-222-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this AD. We will consider all comments received by the closing date and may amend this AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov, including any ( printed page 7556) personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this AD.

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), 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.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

Adoption of the Amendment

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

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

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

2. The FAA amends § 39.13 by adding the following new AD:

2009-03-01 Learjet: Amendment 39-15802. Docket No. FAA-2009-0054; Directorate Identifier 2008-NM-222-AD.

Effective Date

(a) This airworthiness directive (AD) is effective March 5, 2009.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Learjet Model 55, 55B, and 55C airplanes, certificated in any category; serial numbers 002 through 147 inclusive.

Subject

(d) Air Transport Association (ATA) of America Code 25: Equipment/Furnishings.

Unsafe Condition

(e) This AD results from a report of a cabin fire in the left-hand upper cabin fuselage above the aft cabin window at frame 23. We are issuing this AD to detect and correct improper installation of the lavatory light assembly, which could result in contact between the electrical terminals of the light assembly and an adjacent oxygen supply line, and consequent short circuit or fire hazard.

Compliance

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

Inspections, Corrective Actions, and Installation

(g) Within 30 days or 25 flight hours after the effective date of this AD, whichever occurs first, do the actions specified in paragraphs (g)(1) and (g)(2) of this AD. Do the actions in accordance with the Accomplishment Instructions of Bombardier Alert Service Bulletin A55-25-7, dated December 17, 2008.

(1) Do a general visual inspection of the installation of the forward light assembly in the aft lavatory to determine the location of the terminal connector; do a general visual inspection for damage of the light assembly terminals, wires, and oxygen lines; do a general visual inspection to determine if the cable nipple is installed over the light assembly terminal; and do all applicable corrective actions. Do all applicable 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.”

(2) Install a clamp and hardware to the forward side of the frame to maintain the distance specified in Bombardier Alert Service Bulletin A55-25-7, dated December 17, 2008, between the light assembly and oxygen line.

No Reporting

(h) Although Bombardier Alert Service Bulletin A55-25-7, dated December 17, 2008, specifies to submit certain information to the manufacturer, this AD does not include that requirement.

Alternative Methods of Compliance (AMOCs)

(i)(1) The Manager, Wichita Aircraft Certification Office, 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: Daniel Hilton, Aerospace Engineer, Electrical Systems and Avionics Branch, ACE-119W, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4173; fax (316) 946-4107.

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office (FSDO). The AMOC approval letter must specifically reference this AD.

Material Incorporated by Reference

(j) You must use Bombardier Alert Service Bulletin A55-25-7, dated December 17, 2008, 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 this service information 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 or 425-227-1152.

(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 NARA, call 202-741-6030, or go ( printed page 7557) to: http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.