AD 97-01-07

This amendment adopts a new airworthiness directive (AD), applicable to all British Aerospace Model BAe 146 and Avro 146-RJ series airplanes, that requires modification of the left and right elevators, and replacement of the elevator spring with a stiffer spring. This amendment is prompted by reports indicating that water and ice have accumulated at the trailing edge of the left and right elevators; this accumulation can cause the elevators to become unbalanced, and oscillate or flutter. The actions specified by this AD are intended to prevent this oscillation or flutter. Elevator oscillation, if not corrected, could result in reduced controllability of the airplane. Elevator flutter, if not corrected, could couple with the natural vibrations of the airplane, and result in loss of the airplane s structural integrity.

Final rule

97-01-07 BRITISH AEROSPACE REGIONAL AIRCRAFT LIMITED, AVRO INTERNATIONAL AEROSPACE DIVISION (Formerly British Aerospace, plc; British Aerospace Commercial Aircraft Limited): Amendment 39-9878. Docket 96-NM-51-AD.
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 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 (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 the left and right elevators from oscillating or fluttering, which could result in either reduced controllability of the airplane, or loss of the airplane s structural integrity, accomplish the following:

(a) Within 12 months after the effective date of this AD, accomplish the requirements of paragraphs (a)(1) and (a)(2) of this AD.

(1) Modify the left and right elevators by installing mass balance weights at the leading edge of the horn, forward of the elevator hinge line, in accordance with British Aerospace Service Bulletin SB.55-014-01510A, dated December 15, 1995. And

(2) Replace the left and right elevator spring with a stiffer spring, in accordance with British Aerospace Service Bulletin SB.27-150-01510B, dated December 15, 1995.

(b) As of 12 months after the effective date of this AD, no person shallinstall on any airplane an elevator that has not been modified in accordance with paragraph (a) of this AD.

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

(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.

(e) The modification and replacement shall be done in accordance with British Aerospace Service Bulletin SB.55-014-01510A, dated December 15, 1995; and British Aerospace Service Bulletin SB.27-150-01510B, dated December 15, 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 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.

(f) This amendment becomes effective on February 13, 1997.

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 October 18, 1996 (61 FR 54362). That action proposed to require modification of the left and right elevators by installation of mass balance weights at the leading edge of the horn, forward of the hinge line; and replacement of the elevator spring with a stiffer spring.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public.

Conclusion
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 British Aerospace Model BAe 146 and Avro 146-RJ series 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 actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $700 per airplane. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $73,840, or $1,420 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 havesufficient 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 theFederal 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: