AD 93-14-16 ACTIVE

93-14-16 BRITISH AEROSPACE (COMMERCIAL AIRCRAFT), LIMITED: Amendment 39-8640. Docket 93-NM-03-AD.
Applicability: Model ATP airplanes having aft isolator bracket attachment bolts, part number A102-4E or A102-5E; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent structural failure of the engine support structure, accomplish the following:

(a) For airplanes on which the aft isolator bracket attachment bolts have accumulated less than 5,000 total landings as of the effective date of this AD: Prior to the accumulation of 5,000 total landings on the bolts, or within 1,250 hours time-in-service after the effective date of this AD, whichever occurs later, remove the bolts and replace them with new or serviceable parts, in accordance with Jetstream Aircraft, Limited, Service Bulletin ATP-54-9, dated December 9, 1992, or Revision 1, dated May 10, 1993. Thereafter, prior to the accumulation of 5,000 total landings onany bolt, replace it with a new or serviceable bolt, in accordance with the service bulletin.

(b) For airplanes on which the aft isolator bracket attachment bolts will have accumulated 5,000 or more total landings before it is replaced in accordance with paragraph (a) of this AD: Prior to the accumulation of 5,000 total landings or within 150 hours time-in-service after the effective date of this AD, whichever occurs later, perform a visual inspection of the aft isolator bracket attachment bolts to determine if each bolt is in position, and to detect failed or cracked bolts, in accordance with Jetstream Aircraft, Limited, Service Bulletin ATP-54-9, dated December 9, 1992, or Revision 1, dated May 10, 1993.

(1) If any bolt is missing, failed, or cracked, prior to further flight, replace all four bolts in the assembly with new or serviceable parts, in accordance with the service bulletin. Thereafter, prior to the accumulation of 5,000 total landings on any bolt, replace it with a new or serviceable bolt, in accordance with the service bulletin.

(2) If no bolt is missing, failed, or cracked, repeat the visual inspection thereafter at intervals not to exceed 150 hours time-in-service. Within 1,250 hours time-in-service after the effective date of this AD, replace each bolt with a new or serviceable part, in accordance with the service bulletin. Thereafter, prior to the accumulation of 5,000 total landings on any bolt, replace it with a new or serviceable bolt, in accordance with the service bulletin.

(c) Replacement of the existing bolts on the aft isolator brackets on the engine mounting beams with improved bolts (Modification 35256A) in accordance with Jetstream Aircraft, Limited, Service Bulletin ATP-54-10-35256A, Revision 1, dated April 16, 1993, constitutes terminating action for replacement of the bolts every 5,000 landings, as required by paragraphs (a), (b)(1), and (b)(2) of this AD.

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

(e) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished.

(f) The replacement and inspection shall be done in accordance with Jetstream Aircraft, Limited, Service Bulletin ATP-54-9, dated December 9, 1992; or Jetstream Aircraft, Limited, Service Bulletin ATP-54-9, Revision 1, dated May 10, 1993. The modification shall be done in accordance with Jetstream Aircraft, Limited, Service Bulletin ATP-54-10-35256A, Revision 1, dated April 16, 1993, which contains the following list of effective pages:

Page Number
Revision Level
Shown on Page
Date
Shown on Page
1
1
April 16, 1993
2-5
0
March 2, 1993
6
(This page is not used)

7
1
(Not Dated)

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 Jetstream Aircraft, Inc., P.O. Box 16029, Dulles International Airport, Washington, DC 20041-6029. 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.

(g) This amendment becomes effective on October 4, 1993.