05-23510. Airworthiness Directives; Learjet Model 45 Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Final rule; request for comments.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for certain Learjet Model 45 airplanes. This AD requires modifying the electrical wire bundle for the alternator on the left-hand engine, inspecting for clearance between wire harnesses and engine tubing for each engine, and corrective actions if necessary. For certain airplanes, this AD also requires replacing the fuses for the hydraulic shutoff valves with fuses having higher amperage. This AD results from a report of a fire in the left-hand engine nacelle. We are issuing this AD to prevent chafing between the wire bundle for the alternator on each engine and the hydraulic lines, which could result in a fire in the engine nacelle.

DATES:

This AD becomes effective December 20, 2005.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in the AD as of December 20, 2005.

We must receive comments on this AD by February 3, 2006.

ADDRESSES:

Use one of the following addresses to submit comments on this AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401, Washington, DC 20590.
• Fax: [phone].
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942, for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT:

James P. Galstad, Aerospace Engineer, Systems and Propulsion Branch, ACE-116W, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Discussion

We have received a report of a fire in the left-hand engine nacelle on a Learjet Model 45 airplane. Investigation revealed that an electrical wire bundle for the engine alternator had chafed a hole in a hydraulic line. This condition, if not corrected, could result in a fire in the engine nacelle.

Relevant Service Information

We have reviewed Bombardier Alert Service Bulletin SB A40-71-01, dated September 29, 2005 (for Learjet Model 45 airplanes with serial numbers (S/Ns) 45-2001 through 45-2029 inclusive); and Bombardier Alert Service Bulletin SB A45-71-4, dated September 29, 2005 (for Learjet Model 45 airplanes with S/Ns 45-005 through 45-273 inclusive). These service bulletins describe procedures for modifying the electrical wire bundle for the alternator on the left-hand engine to separate the wiring from the hydraulic pump lines and to protect the wiring; inspecting the left and right engines to make sure that the proper clearances are maintained between all wiring harnesses and engine tubing; and correcting improper clearances if necessary. The service bulletins also specify sending a compliance report to the manufacturer.

We have also reviewed Bombardier Service Bulletin SB 40-24-01, dated April 22, 2005 (for Learjet Model 45 airplanes with S/Ns 45-2001 through 45-2015 inclusive); and Bombardier Service Bulletin SB 45-24-6, dated April 22, 2005 (for Learjet Model 45 airplanes with serial numbers 45-005 through 45-254 inclusive). The actions in these service bulletins must be accomplished before or concurrently with Bombardier Alert Service Bulletins SB A40-71-01 and SB A45-71-4. Bombardier Service Bulletin SB 40-24-01 and SB 45-24-6 describe procedures for replacing the fuses for the hydraulic shutoff valves with fuses having higher amperage.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

FAA's Determination and Requirements of This AD

The unsafe condition described previously is likely to exist or develop on other airplanes of the same type design. For this reason, we are issuing this AD to prevent chafing between the wire bundle for the alternator on each engine and the hydraulic lines, which could result in a fire in the engine nacelle. This AD requires accomplishing the actions specified in the applicable service information described previously, except as discussed under “Difference Between the AD and Bombardier Alert Service Bulletins SB A40-71-01 and SB A45-71-4.”

Difference Between the AD and Bombardier Alert Service Bulletins SB A40-71-01 and SB A45-71-4

Although Bombardier Alert Service Bulletins SB A40-71-01 and SB A45-71-4 specify sending a compliance report to the manufacturer, this AD does not include that requirement.

Clarification of Inspection Terminology

In this AD, the “inspecting for proper clearance” specified in Bombardier Alert Service Bulletins SB A40-71-01 and SB A45-71-4, is referred to as a “general visual inspection.” We have included the definition for this inspection in a note in the AD.

FAA's Determination of the Effective Date

Since an unsafe condition exists that requires the immediate adoption of this AD, we have found that notice and opportunity for public comment before issuing this AD are impracticable, and that good cause exists to make this AD effective in less than 30 days.

Comments Invited

This AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any relevant written data, views, or arguments regarding this AD. Send your comments to an address listed in the ADDRESSES section. Include “Docket No. FAA-2005-23144; Directorate Identifier 2005-NM-218-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD that might suggest a need to modify it.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Dockets

You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

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 have determined that 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 the 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); 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.

We prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

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

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

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

§ 39.13

[Amended]

2. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

2005-24-13 Learjet: Amendment 39-14393. Docket No. FAA-2005-23144; Directorate Identifier 2005-NM-218-AD.

Effective Date

(a) This AD becomes effective December 20, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Learjet Model 45 airplanes, certificated in any category; serial numbers (S/Ns) 45-005 through 45-273 inclusive, and 45-2001 through 45-2029 inclusive.

Unsafe Condition

(d) This AD results from a report of a fire in the left-hand engine nacelle. We are issuing this AD to prevent chafing between the wire bundle for the alternator on each engine and the hydraulic lines, which could result in a fire in the engine nacelle.

Compliance

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

Modification

(f) Within 50 flight hours after the effective date of this AD: Modify the electrical wire bundle for the alternator on the left-hand engine; and do a general visual inspection of the left and right engines to make sure that the proper clearances are maintained between all wiring harnesses and engine tubing. Correct improper clearances before further flight. Do all actions in accordance with the Accomplishment Instructions of the applicable service bulletin in paragraph (f)(1) or (f)(2) of this AD.

(1) For Learjet Model 45 airplanes with S/Ns 45-2001 through 45-2029 inclusive: Bombardier Alert Service Bulletin SB A40-71-01, dated September 29, 2005.

(2) For Learjet Model 45 airplanes with S/Ns 45-005 through 45-273 inclusive: Bombardier Alert Service Bulletin SB A45-71-4, dated September 29, 2005.

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.”

Concurrent Requirement

(g) For airplanes with S/Ns identified in paragraphs (g)(1) and (g)(2) of this AD: Before or concurrently with the modification required by paragraph (f) of this AD, replace the fuses for the hydraulic shutoff valves with fuses having higher amperage in accordance with the Accomplishment Instructions of the applicable service bulletin in paragraph (g)(1) or (g)(2) of this AD.

(1) For Learjet Model 45 airplanes with S/Ns 45-2001 through 45-2015 inclusive: Bombardier Service Bulletin SB 40-24-01, dated April 22, 2005.

(2) For Learjet Model 45 airplanes with S/Ns 45-005 through 45-254 inclusive: Bombardier Service Bulletin SB 45-24-6, dated April 22, 2005.

No Reporting Requirement

(h) Although Bombardier Alert Service Bulletin SB A40-71-01, dated September 29, 2005; and Bombardier Alert Service Bulletin SB A45-71-4, dated September 29, 2005; specify sending a compliance report to the manufacturer, this AD does not include that requirement.

Alternative Methods of Compliance (AMOCs)

(i)(1) The Manager, Wichita Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Material Incorporated by Reference

(j) You must use the service information listed in Table 1 of this AD to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference of these documents in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942, for a copy of this service information. You may review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, Nassif Building, Washington, DC; on the Internet at http://dms.dot.gov; or at the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call [phone], or go to http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

Table 1.—Material Incorporated by Reference

Bombardier service bulletin	Date
Alert Service Bulletin SB A40-71-01	September 29, 2005.
Alert Service Bulletin SB A45-71-4	September 29, 2005.
Service Bulletin SB 40-24-01	April 22, 2005.
Service Bulletin SB 45-24-6	April 22, 2005.

Issued in Renton, Washington, on November 18, 2005.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.