AD 95-15-02

This amendment adopts a new airworthiness directive (AD), applicable to all British Aerospace Model Viscount 744, 745D, and 810 airplanes, that requires an inspection of fittings of the engine mount structure to determine whether fasteners have been installed in inspection holes and to determine whether those holes are oversized. It also requires various follow-on actions, depending upon the results of the inspection. This amendment is prompted by reports indicating that fasteners were installed in the inspection hole of the engine "W" frame socket fittings and the inspection hole was oversized due to fatigue cracking. The actions specified by this AD are intended to prevent such fatigue cracking, which could lead to failure of the fasteners and consequent separation of the engine from the airframe.

Final rule

95-15-02 BRITISH AEROSPACE REGIONAL AIRCRAFT LIMITED (Formerly British Aerospace Commercial Aircraft Limited, Vickers-Armstrongs Aircraft Limited): Amendment 39-9305. Docket 94-NM-112-AD.
Applicability: All Model Viscount 744, 745D, and 810 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 use the authority provided in paragraph (c) of this AD to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effectof the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD.

Compliance: Required as indicated, unless accomplished previously.

To prevent fatigue cracking, which could lead to the possible separation of the engine from the airframe, accomplish the following:

(a) Within 12 months after the effective date of this AD, perform a detailed visual inspection of "W" frame socket fittings of the engine mount structure to determine whether drive screws or blind rivets have been installed in inspection holes and to determine whether those holes are oversized, in accordance with the Accomplishment Instructions, section 2.1 PART ONE, paragraphs A., B., C., D., E., and F., of British Aerospace Preliminary Technical Leaflet (PTL) 501, dated May 1, 1994.

(b) If drive screws or blind rivets are found installed, or if the inspection holes arefound to be oversized, during the inspection required by paragraph (a) of this AD, at the next scheduled engine removal, but no later than 12 months after the effective date of this AD, perform a nondestructive test (NDT) to detect discontinuities (i.e., cracks, corrosion, and mechanical damage) at inspection holes; rework the hole or replace the "W" frame fitting with a new or serviceable part; and perform the specified follow-on actions; in accordance with the Accomplishment Instructions, section 2.2 PART TWO, paragraphs A., B., C., D., E., and F., of British Aerospace Preliminary Technical Leaflet (PTL) 501, dated May 1, 1994.

(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 inspection and test shall be done in accordance with British Aerospace Preliminary Technical Leaflet (PTL) 501, dated May 1, 1994, which contains the following list of effective pages:

Page Number
Revision Level
Shown on Page
Date
Shown on Page
1-9
Original
May 1, 1994

APPENDIX 1

1-6
Original
January 1, 1994

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 Ltd., Engineering Support Manager, Military Business Unit, Chadderton Works, Greengate, Middleton, Manchester M24 1SA, 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 August 23, 1995.

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 Viscount 744, 745D, and 810 airplanes was published in the Federal Register on April 19, 1995 (60 FR 19551). That action proposed to require performing a detailed visual inspection of "W" frame socket fittings of the engine mount structure to determine whether drive screws or blind rivets have been installed in inspection holes and to determine whether those holes are oversized. It also proposed to require various follow-on actions, depending upon the results of the inspection.

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. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

The FAA estimates that 29 airplanes of U.S. registry will be affected by this AD, that it will take approximately 25 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 total cost impact of the AD on U.S. operators is estimated to be $43,500, or $1,500 per airplane.

The total 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.

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. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.

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