AD 98-26-05

This amendment adopts a new airworthiness directive (AD) that applies to all British Aerospace (Operations) Limited (British Aerospace) Model B.121 Series 1, 2, and 3 airplanes. This AD requires repetitively inspecting (using visual methods) the internal and external surfaces of the brake torque tube assemblies in the cockpit area for cracks. This AD also requires obtaining and incorporating repair procedures for any brake torque tube assembly found cracked. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the United Kingdom. The actions specified by this AD are intended to detect and correct cracks in the brake torque tube assemblies, which could result in reduced brake efficiency with possible reduced and/or loss of airplane control.

Final rule.

98-26-05 BRITISH AEROSPACE (OPERATIONS) LIMITED: Amendment 39-10946; Docket No. 97-CE-122-AD.

Applicability: Model B.121 Series 1, 2, and 3 airplanes, all serial numbers, 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 (d) 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 in the body of this AD, unless already accomplished.

To detect and correct cracks in the brake torque tube assemblies, which could result in reduced brake efficiency with possible reduced and/or loss of airplane control, accomplish the following:

(a) Upon accumulating 3,300 hours time-in-service (TIS) on each brake torque tube assembly or within the next 100 hours TIS after the effective date of this AD, whichever occurs later, and thereafter at intervals not to exceed 600 hours TIS, visually inspect each brake torque tube assembly for cracks. Accomplish this inspection in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of Jetstream Aircraft Ltd. PUP Service Bulletin No. B121/103, ORIGINAL ISSUE: October 26, 1995.

(b) If a crack(s) is found during any inspection required by paragraphs (a) or (b)(2) of this AD, prior to further flight, accomplish the following:

(1) Obtain repair instructions from the manufacturer through the FAA, Small Airplane Directorate, at the address specified in paragraph (d) of this AD; and

(2) Incorporate these repair instructions, and continue to reinspect at intervals not to exceed 600 hours TIS.

(c) 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.

(d) An alternative method of compliance or adjustment of the initial or repetitive compliance times that provides an equivalent level of safety may be approved by the Manager, Small Airplane Directorate, 1201 Walnut, suite 900, Kansas City, Missouri 64106. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Small Airplane Directorate.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Small AirplaneDirectorate.

(e) Questions or technical information related to Jetstream Aircraft Ltd. PUP Service Bulletin No. B121/103, ORIGINAL ISSUE: October 26, 1995, should be directed to British Aerospace (Operations) Limited, British Aerospace Regional Aircraft, Prestwick International Airport, Ayrshire, KA9 2RW, Scotland; telephone: (01292) 479888; facsimile: (01292) 479703. This service information may be examined at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

(f) The inspection required by this AD shall be done in accordance with Jetstream Aircraft Ltd. PUP Service Bulletin No. B121/103, ORIGINAL ISSUE: October 26, 1995. 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 (Operations) Limited, British Aerospace Regional Aircraft, Prestwick International Airport, Ayrshire,KA9 2RW, Scotland. Copies may be inspected at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

NOTE 3: The subject of this AD is addressed in British AD 003-10-95, not dated.

(g) This amendment becomes effective on January 29, 1999.

Events Leading to the Issuance of This AD
A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to all British Aerospace Model B.121 Series 1, 2, and 3 airplanes was published in the Federal Register as a notice of proposed rulemaking (NPRM) on September 14, 1998 (63 FR 49050). The NPRM proposed to require repetitively inspecting (using visual methods) the internal and external surfaces of the brake torque tube assemblies in the cockpit area for cracks. The NPRM also proposed to require obtaining and incorporating repair procedures for any brake torque tube assembly found cracked. Accomplishment of the proposed action as specified in the NPRM would be required in accordance with Jetstream Aircraft Ltd. PUP Service Bulletin No. B121/103, ORIGINAL ISSUE: October 26, 1995. Accomplishment of the proposed repair, if necessary, would be required in accordance with procedures obtained from the manufacturer through the FAA, Small Airplane Directorate.

The NPRM was the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the United Kingdom.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposed rule or the FAA's determination of the cost to the public.

The FAA's Determination
After careful review of all available information related to the subject presented above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed except for minor editorial corrections. The FAA has determined that these minor corrections will not change the meaning of the AD and will not add any additional burden upon the public than was already proposed.

Cost Impact
The FAA estimates that 2 airplanes in the U.S. registry will be affected by the initial inspection required by this AD, that it will take approximately 5 workhours per airplane to accomplish this initial inspection, and that the average labor rate is approximately $60 an hour. Based on these figures, the total cost impact of the initial inspection on U.S. operators is estimated to be $600, or $300 per airplane. These figures only take into account the costs of the initial inspection and do not take into account the costs for any repetitive inspections or the costs associated with repairing or replacing any cracked torque tube assemblies found during any inspection required by this AD. The FAA has no way of determining how many torque tube assemblies will be found cracked or how many repetitive inspections each owner/operator will incur over the life of the affected airplanes.

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 copy of the final 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, 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 a new airworthiness directive (AD) to read as follows: