2011-17265. Airworthiness Directives; Learjet Inc. Model 45 Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD would require revising the maintenance program to incorporate life limits for the main landing gear (MLG) actuator end cap. This proposed AD was prompted by a report of the potential for fatigue cracking of the end cap of the MLG prior to the published life limitation. We are proposing this AD to prevent fatigue cracking of the end cap of the MLG, which could result in the failure of the MLG actuator upon landing, and failure of the MLG to extend or retract during flight.

DATES:

We must receive comments on this proposed AD by August 22, 2011.

ADDRESSES:

You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• 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, Kansas 67209-2942; telephone [phone]; fax [phone]; e-mail [e-mail]; 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, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

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]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Paul Chapman, Aerospace Engineer, Aviation Safety, ACE-118W, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, KS 67209; phone: [phone]; fax: [phone]; e-mail: [e-mail].

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-2011-0651; Directorate Identifier 2011-NM-041-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 from Learjet that indicated the life limitation of the main landing gear actuator was determined using fatigue testing during the Model 45 certification; however, the supplier discovered they had not tested the actuator properly during subsequent testing for another application. Learjet identified the potential for fatigue cracking of the end cap of the main landing gear actuator prior to the published life limitation. This potential for fatigue cracking, if not corrected, could result in failure of the main landing gear actuator upon landing, and failure of the MLG to extend or retract during flight.

Relevant Service Information

We reviewed Learjet 40 Temporary Revision 4-23, dated January 24, 2011, to Learjet 40 Maintenance Manual MM-105; and Learjet 45 Temporary Revision 4-34, dated January 24, 2011, to Learjet 45 Maintenance Manual MM-104. Among other things, the Airworthiness Limitations sections contained in Learjet 40 Temporary Revision 4-23 and Learjet 45 Temporary Revision 4-34 provide new life limits and replacement compliance times for the MLG actuator end cap.

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 these same type designs.

Proposed AD Requirements

This proposed AD would require revising the maintenance program to incorporate life limits for the MLG actuator end cap.

Costs of Compliance

We estimate that this proposed AD affects 351 airplanes of U.S. registry. We estimate the following costs to comply with this proposed AD:

Estimated costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Revise maintenance plan	1 work-hour × $85 per hour = $85 per revision	$0	$85 per revision	$29,835

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

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 FAA amends § 39.13 by adding the following new airworthiness directive (AD):

Learjet Inc.: Docket No. FAA-2011-0651; Directorate Identifier 2011-NM-041-AD.

Comments Due Date

(a) We must receive comments by August 22, 2011.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Learjet Inc. Model 45 airplanes, certificated in any category; all serial numbers.

Note 1:

This AD requires revisions to certain operator maintenance documents to include new actions (e.g. inspections). Compliance with these actions is required by 14 CFR 91.403(c). For airplanes that have been previously modified, altered, or repaired in the areas addressed by these actions, the operator may not be able to accomplish the actions described in the revisions. In this situation, to comply with 14 CFR 91.403(c), the operator must request approval for an alternative method of compliance according to paragraph (i) of this AD. The request should include a description of changes to the required actions that will ensure the continued operational safety of the airplane.

Subject

(d) Air Transport Association (ATA) of America Code 32: Landing Gear.

Unsafe Condition

(e) This AD was prompted by a report of the potential for fatigue cracking of the end cap of the main landing gear (MLG) prior to the published life limitation. We are issuing this AD to prevent fatigue cracking of the end cap of the MLG, which could result in the failure of the MLG actuator upon landing, and failure of the MLG to extend or retract during flight.

Compliance

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

Maintenance Program Revision

(g) Within 30 days after the effective date of this AD, revise the maintenance program by incorporating IRN T3220105 (Main Landing Gear Actuator End Cap (P/N 200-0303)) as specified in Learjet 40 Temporary Revision 4-23, dated January 24, 2011, to Learjet 40 Maintenance Manual MM-105; or Learjet 45 Temporary Revision 4-34, dated January 24, 2011, to Learjet 45 Maintenance Manual MM-104; as applicable. The initial compliance for the replacement specified in IRN T3220105 is prior to the accumulation of 2,387 total flight cycles on the end cap (P/N 200-0303), or within 25 flight cycles after the effective date of this AD, whichever occurs later.

No Alternative Actions or Intervals

(h) After accomplishing the revision required by paragraph (g) of this AD, no alternative actions (e.g., replacements) or intervals, may be used, unless the actions or intervals are approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (i) of this AD.

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 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. The AMOC approval letter must specifically reference this AD.

Related Information

(j) For more information about this AD, contact Paul Chapman, Aerospace Engineer, Aviation Safety, ACE-118W, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, KS 67209; phone: [phone]; fax: [phone]; e-mail: [e-mail].

(k) For service information identified in this AD, contact Learjet, Inc., One Learjet Way, Wichita, Kansas 67209-2942; telephone [phone]; fax [phone]; e-mail [e-mail]; 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, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

Issued in Renton, Washington, on June 29, 2011.

Jeffrey E. Duven,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.