01-21631. Airworthiness Directives; Boeing Model 737-100, -200, -200C, -300, -400, and -500 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This proposal would require inspection of landing gear parts and/or their records to see that parts have serial numbers and that each part's number of flight cycles has been tracked; assignment of serial numbers and flight cycle use numbers if necessary; and removal of individual landing gear components from service when they reach their life limit. This action is necessary to prevent failure of landing gear parts, which could lead to landing gear collapse. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by October 12, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-343-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2000-NM-343-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

The service information referenced in the proposed rule may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

James Blilie, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2000-NM-343-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-343-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports that a check by the manufacturer of the list of Model 737 series airplane main and nose landing gear life-limited parts revealed that some life-limited parts were not included on the list. Those life-limited parts have now been added to the 737 Main Landing Gear and Nose Landing Gear Components Interchangeability Lists (drawings). Failure to remove “safe life” parts at their life limit could result in failure of landing gear parts, which could lead to landing gear collapse.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Service Bulletin 737-32-1322, dated September 30, 1999, which describes procedures for examining records and/or landing gear parts to verify that parts identified in this service bulletin have serial numbers on them; for assigning and marking serial numbers on parts if necessary; for examining records to find out if flight cycles for the landing gear parts identified in this service bulletin have been tracked; for assigning a number of flight cycles to parts for tracking purposes, if necessary; and for removing landing gear parts from service when they reach their life limit. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.

Boeing Service Bulletin 737-32-1322, dated September 30, 1999, refers to Boeing Drawing 65C73761—737 Main Landing Gear Components Interchangeability List, and Boeing Drawing 65C73762—737 Nose Landing Gear Components Interchangeability List, as additional sources of service information for accomplishment of the removal of landing gear parts from service when they reach their life limit.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the service bulletin described previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

Operators should note that, although the service bulletin recommends that the serial numbers assigned to parts must be different for each part, it does not define a process to ensure that duplicate serial numbers will not be issued. This proposal would require that the serialization of those parts' numbers be accomplished per a method approved by the FAA.

Cost Impact

There are approximately 3,132 airplanes of the affected design in the worldwide fleet. The FAA estimates that 1,099 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 1 work hour per airplane to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $65,940, or $60 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that 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); and (3) if promulgated, 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. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness directive:

Boeing: Docket 2000-NM-343-AD.

Applicability: Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, certificated in any category, line numbers 1 through 3132, inclusive.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (g) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of landing gear parts, which could lead to landing gear collapse, accomplish the following:

Inspection of Parts and/or Records

(a) During the next gear overhaul, or within 10 years from the effective date of this AD, whichever occurs later, examine records and/or landing gear parts in accordance with Boeing Service Bulletin 737-32-1322, dated September 30, 1999, to determine whether parts have serial numbers and whether the number of flight cycles for each part has been tracked. If landing gear parts have serial numbers in accordance with Boeing Service Bulletin 737-32-1322, dated September 30, 1999, and the number of flight cycles has been tracked, no further action is necessary for paragraphs (a), (b), or (c) of this AD.

Assignment of Serial Numbers and Flight Cycles

(b) If any part examined as mandated in paragraph (a) of this AD does not have serial numbers, during the next gear overhaul, or within 10 years from the effective date of this AD, whichever occurs later, assign serial numbers to those parts using a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, and mark them on the parts in accordance with Boeing Service Bulletin 737-32-1322, dated September 30, 1999.

(c) If flight cycles for any part examined as mandated in paragraph (a) of this AD have not been tracked, during the next gear overhaul, or within 10 years from the effective date of this AD, whichever occurs later, assign a number of lifetime flight cycles to that part in accordance with Part 2. B. of the Accomplishment Instructions of Boeing Service Bulletin 737-32-1322, dated September 30, 1999.

Removal from Service at Life Limit

(d) When any landing gear part has reached its life limit number of flight cycles, as described in Part 2. B. of the Accomplishment Instructions of Boeing Service Bulletin 737-32-1322, dated September 30, 1999, remove that part from service.

Spare Parts

(e) As of the effective date of this AD, no person shall install on any airplane a landing gear part unless it has been assigned a serial number and a lifetime flight cycle number in accordance with the requirements of this AD.

(f) As of the effective date of this AD, no person shall install on any airplane a landing gear part that has reached its life limit of flight cycles, in accordance with Boeing Service Bulletin 737-32-1322, dated September 30, 1999.

Alternative Methods of Compliance

(g) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

Special Flight Permits

(h) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Issued in Renton, Washington, on August 21, 2001.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.