AD 99-22-11

This amendment adopts a new airworthiness directive (AD), applicable to all British Aerospace Model BAe 146 and Avro 146-RJ series airplanes, that requires installation of modified roller sub-assemblies in both the main landing gear (MLG) door lock and the MLG uplock. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this AD are intended to prevent failure of the roller sub-assemblies, which could result in failure of the MLG to retract and lock after takeoff, or to deploy properly for landing.

Final rule

99-22-11 BRITISH AEROSPACE REGIONAL AIRCRAFT (Formerly British Aerospace Regional Aircraft Limited, Avro International Aerospace Division; British Aerospace, PLC; British Aerospace Commercial Aircraft Limited): Amendment 39-11389. Docket 99-NM-27-AD. Issued October 19, 1999.
Applicability: All Model BAe 146 and Avro 146-RJ series airplanes, certificated in any category.

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 (c) 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 the roller sub-assemblies in both the main landing gear (MLG) door lock and the MLG uplock, which could result in failure of the MLG to retract and lock after takeoff, or to deploy properly for landing, accomplish the following:

Modification
(a) Install a modified roller sub-assembly in the MLG door lock unit and the MLG uplock unit (British Aerospace Modification HCM70656A), in accordance with British Aerospace Service Bulletin SB.32-150-70656A, dated December 1, 1998, at the applicable time specified in paragraph (a)(1), (a)(2), (a)(3), or (a)(4) of this AD.

(1) For airplanes that have accumulated 30,000 total flight cycles or more as of the effective date of this AD: Within six months after the effective date of this AD.

(2) For airplanes that have accumulated 26,000 or more, but fewer than 30,000 total flight cycles as of the effective date of this AD: Within 12 months after the effective date of this AD.

(3) For airplanes that have accumulated 22,000 or more, but fewer than 26,000 total flight cycles as of the effective date of this AD: Within 18 months after the effective date of this AD.

(4) For airplanes that have accumulated fewer than 22,000 total flight cycles as of the effective date of this AD: Within 18 months after the accumulation of 22,000 total flight cycles.

NOTE 2: Accomplishment of British Aerospace Modification HCM70656B (installation of improved rollers) is acceptable for compliance with the requirements of paragraph (a) of this AD.

(b) As of the effective date of this AD, no person shall install on any airplane a MLG door lock assembly, part number 200898001 or 200898002, or a MLG uplock assembly, part number 200885001 or 200885002.

Alternative Methods of Compliance
(c) 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, International Branch, ANM-116, FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

Special Flight Permits
(d) 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.

Incorporation by Reference
(e) The actions shall be done in accordance with British Aerospace Service Bulletin SB.32-150-70656A, dated December 1, 1998. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from British Aerospace Regional Aircraft American Support, 13850 Mclearen Road, Herndon, Virginia 20171. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

NOTE 4: The subject of this AD is addressed in British airworthiness directive 005-12-98.

(f) This amendment becomes effective on December 2, 1999.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to all British Aerospace Model BAe 146 and Avro 146-RJ series airplanes was published in the Federal Register on July 7, 1999 (64 FR 36626). That action proposed to require installation of modified roller sub-assemblies in both the main landing gear (MLG) door lock and the MLG uplock.

Comments Received
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

Request to Include Alternate Modification
One commenter, the manufacturer, requests that the proposed AD allow reference to an improved roller which will be approved in the near future. British Aerospace Service Bulletin SB.32-150-70656A, dated December 1, 1998, which is referenced in the proposed AD as the appropriate source of service information, introduces an interim standard roller for the main landing gear door lock and uplock (reference British Aerospace Modification HCM70656A). However, the commenter advises that an improved roller is to be introduced in the next two months as British Aerospace Modification HCM70656B. According to the commenter, this modification is being addressed with the Civil Aviation Authority (CAA), which is the airworthiness authority of the United Kingdom, and is expected to be approved as an alternative method of compliance. The commenter requests that this alternative modification be referenced in the AD in order to allow operators to readily take advantage of either method of compliance.

The FAA concurs. The FAA has received additional information from the manufacturer regarding the acceptability of the improved roller described in British Aerospace Modification HCM70656B. This modification has now been approved by the CAA of the United Kingdom as an acceptable alternative method of compliance to installation of the standard roller described in Service Bulletin SB.32-150-70656A. Accordingly, the FAA has determined that Modification HCM70656B is an acceptable method of compliance for the requirements of this AD, and has added a "NOTE" to the final rule to provide such credit to operators. A reference to Modification HCM70656A has also been included in paragraph (a) of the AD to clarify the requirements of that paragraph.

Conclusion
After careful review of the available data, including the comment noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact
The FAA estimates that 45 airplanes of U.S. registry will be affected by this AD, that it will take approximately 12 work hours per airplane to accomplish the required modification, and that the average labor rate is $60 per work hour. Required parts will be provided at no cost to the operators. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $32,400, or $720 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

Regulatory Impact
The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."

List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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: