AD 98-12-17

This amendment adopts a new airworthiness directive (AD) that is applicable to all British Aerospace Model Viscount 744, 745, 745D, and 810 series airplanes. This amendment requires repetitive inspections to detect cracking and corrosion of components of the engine nacelle subframe structure, and corrective action, if necessary; and replacement of any component that has reached its life limit (safe life) with a new or serviceable component. This amendment is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified in this AD are intended to ensure periodic replacement of certain engine nacelle subframe components that have reached their maximum life limits. Cracking and corrosion of these components, if not detected and corrected in a timely manner, could result in reduced structural integrity of the engine nacelle subframe structure, separation of the engine from the airframe, and reduced controllability of the airplane.

Direct final rule; confirmation of effective date

98-12-17 BRITISH AEROSPACE REGIONAL AIRCRAFT LIMITED (Formerly British Aerospace Commercial Aircraft Limited, Vickers-Armstrongs Aircraft Limited): Amendment 39-10444. Docket 97-NM-321-AD.
Applicability: All Model Viscount 744, 745, 745D, and 810 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 (f) 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 includespecific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent reduced structural integrity of the engine nacelle subframe structure, separation of the engine from the airframe, and reduced controllability of the airplane, accomplish the following:

(a) Prior to the accumulation of the number of landings corresponding to a strut s life limit (safe life), as specified in the "Inspection Threshold Landings" column of Table One, Two, Three, Four, Five, or Six (hereinafter referred to as "the applicable Table"), as applicable, provided in British Aerospace Viscount Alert Preliminary Technical Leaflet (PTL) 500, dated January 1, 1993, including Appendices 1 through 4 inclusive, dated November 1992, and Appendix 5, dated October 1992; or within 100 flight hours after the effective date of this AD; whichever occurs later: Replace any strut that has reached its life limit, as specified in the applicable Table, with a serviceable strut, in accordance with the alert PTL. Thereafter, replace any strut before it exceeds its life limit with a serviceable strut in accordance with the alert PTL, until initiation of the replacement cycle for that strut, as specified in paragraph (d) of this AD.

(b) Prior to the accumulation of the number of landings corresponding to a strut s inspection threshold, as specified in the "Inspection Period Landings" column of the applicable Table provided in British Aerospace Alert Viscount PTL 500, dated January 1, 1993, including Appendices 1 through 4 inclusive, dated November 1992, and Appendix 5, dated October 1992; or within 100 flight hours after the effective date of this AD; whichever occurs later: Perform a visual inspection to detect cracking of the strut end fittings, in accordance with paragraph 2.1, Part One, Accomplishment Instructions, of the alert PTL. Repeat the inspection thereafter at intervals not to exceed 100 flight hours, until initiation of the inspection cycle for the respective component, as specified in paragraph (d) of this AD.

(c) Prior to the accumulation of the number of landings corresponding to a strut s inspection threshold, as specified in the "Inspection Period Landings" column in the applicable Table provided in British Aerospace Viscount Alert PTL 500, dated January 1, 1993, including Appendices 1 through 4 inclusive, dated November 1992, and Appendix 5, dated October 1992; or within 200 flight hours after the effective date of this AD; whichever occurs later: Perform an eddy current inspection to detect cracking of the strut end fittings, in accordance with paragraph 2.1, Part One, Accomplishment Instructions, of the alert PTL. Repeat the inspection thereafter at intervals not to exceed 200 flight hours, until initiation of the inspection cycle for the respective component, as specified in paragraph (d) of this AD.

(d) Within 6 months after the effective date of this AD, perform an inspection (surfaceeddy scan, rotating eddy bore, internal surface eddy scan, or radiographic, as applicable) to detect cracking and corrosion of components of the engine nacelle subframe; and replace any component that has exceeded its life limit; in accordance with paragraph 2.2, Part Two, Accomplishment Instructions, of British Aerospace Viscount Alert PTL 500, dated January 1, 1993, including Appendices 1 through 4 inclusive, dated November 1992, and Appendix 5, dated October 1992. Repeat the inspection(s) and replacement(s) thereafter at intervals not to exceed the inspection threshold or safe life for the applicable component, as specified in the "Inspection Period Landings" or the "Inspection Threshold Landings" column (respectively) of the applicable Table of the alert PTL. Accomplishment of the initial inspections/replacements for all struts as required by this paragraph constitutes terminating action for the inspection/replacement requirements of paragraphs (a), (b), and (c) of this AD.

(e) If any crack or corrosion is found during any inspection required by this AD: Prior to further flight, accomplish the actions required by either paragraph (e)(1) or (e)(2) of this AD, and continue to follow the inspection and replacement schedule in accordance with the applicable Table.

(1) Replace the discrepant component with a serviceable component. Or

(2) Repair the discrepant part in accordance with a method approved by the Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate.

(f) 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. 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 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

(g) 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.

(h) The actions shall be done in accordance with British Aerospace Alert Preliminary Technical Leaflet 500, dated January 1, 1993; including Appendices 1 through 4 inclusive, dated November 1992, and Appendix 5, dated October 1992. 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, Chadderton Division, Engineering Support, 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.

NOTE 3: The subject of this AD is addressed in British airworthiness directive 008-06-94 (undated).

(i) This amendment becomes effective on July 1, 1998.

The FAA published this direct final rule with request for comments in the Federal Register on April 2, 1998 (63 FR 16111). The FAA uses the direct final rulemaking procedure for a non-controversial rule where the FAA anticipates that there will be no adverse public comment. This direct final rule advised the public that no adverse comments were anticipated, and that unless a written adverse comment, or a written notice of intent to submit such an adverse comment, was received within the comment period, the regulation would become effective on July 1, 1998. No adverse comments were received, and thus this notice confirms that this final rule will become effective on that date.

Issued in Renton, Washington, on June 2, 1998.