AD 96-21-09

This amendment adopts a new airworthiness directive (AD), applicable to all British Aerospace Model BAe 146 series airplanes and certain Model Avro 146-RJ series airplanes, that requires a one-time inspection to detect corrosion of the direction link subassembly of the main landing gear (MLG) assembly, and repair or replacement of the direction link subassembly with a serviceable unit, if necessary. This amendment is prompted by a report of failure of the direction link subassembly due to corrosion. The actions specified by this AD are intended to prevent such failures, which can result in directional control problems of the airplane during landing.

Final rule

96-21-09 BRITISH AEROSPACE REGIONAL AIRCRAFT LIMITED, AVRO INTERNATIONAL AEROSPACE DIVISION (Formerly British Aerospace, plc; British Aerospace Commercial Aircraft Limited): Amendment 39-9786. Docket 96-NM-41-AD.
Applicability: All Model BAe 146 series airplanes and Model Avro 146-RJ series airplanes, as listed in British Aerospace Service Bulletin SB.32-143, dated August 22, 1995; certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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 the direction link subassembly of the main landing gear (MLG), which could result in reduced directional control of the airplane during landing, accomplish the following:

(a) For airplanes that have accumulated 8,000 or more landings on the MLG assembly as of the effective date of this AD, or on which the MLG assembly was manufactured or last overhauled within 4 years prior to the effective date of this AD: Perform a visual inspection to detect corrosion of the direction link subassembly of the MLG assembly at the later of the times specified in paragraph (a)(1) or (a)(2) of this AD, in accordance with British Aerospace Service Bulletin SB.32-143, dated August 22, 1995.

NOTE 2: British Aerospace Service Bulletin SB.32-143, dated August 22, 1995, references Messier-Dowty Service Bulletin 146-32-127, dated August 21, 1995, as an additional source of service information.

(1) Prior to the accumulation of 12,000 total landings, or within 5 years since manufacture or last overhaul, whichever occurs first. Or

(2) Prior to the accumulation of 400 landings on the MLG assembly after the effective date of this AD, or within 2 months after the effective date of this AD, whichever occurs first.

(b) For airplanes not subject to paragraph (a) of this AD: Perform a visual inspection to detect corrosion of the direction link subassembly of the MLG assembly at the later of the times specified in paragraph (b)(1) or (b)(2) of this AD, in accordance with British Aerospace Service Bulletin SB.32-143, dated August 22, 1995.

(1) Prior to the accumulation of 4,000 landings on the MLG assembly after the effective date of this AD. Or

(2) Within 12 months after the effective dateof this AD.

(c) If no corrosion is found during the inspection required by paragraph (a) or (b) of this AD: Prior to further flight, perform the follow-on actions in accordance with British Aerospace Service Bulletin SB.32-143, dated August 22, 1995.

NOTE 3: "Follow-on actions," as specified in this AD, include applying jointing compound to the threads; in some case, restoring the cadmium plate; and applying sealant to the exposed threads and castellations on the direction link subassembly. These actions are described in detail in Messier-Dowty Service Bulletin 146-32-127, dated August 21, 1995.

(d) If light surface corrosion, as defined in British Aerospace Service Bulletin SB.32-143, dated August 22, 1995, is detected during the inspection required by paragraph (a) of this AD: Prior to further flight, remove the corrosion and perform the follow-on actions in accordance with the service bulletin.

(e) If any corrosion is found during the inspection required by paragraph (a) or (b) or this AD, and that corrosion is beyond the limits specified in British Aerospace Service Bulletin SB.32-143, dated August 22, 1995: Prior to, further flight, replace the link subassembly in accordance with the service bulletin.

(f) As of the effective date of this AD, no person shall install a MLG or directional link subassembly unless the inspection and necessary follow-on actions of the directional link subassembly specified in paragraphs (a), (b), (c), and (d) of this AD have been performed, in accordance with British Aerospace Service Bulletin SB.32-143, dated August 22, 1995.

(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, Standardization Branch, ANM-113, 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, Standardization Branch, ANM-113.

NOTE 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Standardization Branch, ANM-113.

(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.

(i) The actions shall be done in accordance with British Aerospace Service Bulletin SB.32-143, dated August 22, 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 5 1. Copies may be obtained from British Aerospace Regional Aircraft Limited, Avro International Aerospace Division, Customer Support, Woodford Aerodrome, Woodford, Cheshire SK7 1QR, England. 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.

(j) This amendment becomes effective on November 29, 1996.

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 series airplanes and certain Model Avro 146-RJ series airplanes was published in the Federal Register on August 12, 1996 (61 FR 41755). That action proposed to require a one-time visual inspection to detect corrosion of the direction link subassembly of the main landing gear (MLG) assembly, and repair or replacement of the direction link subassembly with a serviceable part, if necessary. That action also proposed to require certain follow-on procedures (application of a jointing compound to the threads of the direction link tube) if light surface corrosion is detected or if no corrosion is detected.

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

Thecommenter supports the proposed rule.

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 as proposed.

Cost Impact
The FAA estimates that 52 airplanes of U.S. registry will be affected by this AD, that it will take approximately 3 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $9,360, or $180 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.

Should an operator be required to accomplish the replacement of the link subassembly, it will be accomplished concurrently with the required inspection and take approximately no more work hours than the inspection itself. Replacement parts will cost approximately $8,200 per airplane. Based on these figures, the cost impact of any necessary replacement action is estimated to be $8,200 per airplane.

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, 4470 1.

39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: