91-25-07 BRITISH AEROSPACE: Amendment 39-8108. Docket No. 91-NM-134-AD. Supersedes AD 91-09-13, Amendment 39-6979.
Applicability: All Model ATP series airplanes which have not installed Modification 10170A (described in British Aerospace Service Bulletin ATP-55-5), certificated in any category.
Compliance: Required as indicated, unless previously accomplished.
To prevent reduced directional control of the airplane due to impairment of the operation of the rudder, accomplish the following:
(a) For airplanes with rudders in pre-Modification 10165A configuration: Prior to the accumulation of 750 hours time-in-service, or within 125 hours time-in-service after May 28, 1991 (the effective date of AD 91-09-13, Amendment 39-6979), whichever occurs later, and thereafter at intervals not to exceed 125 hours time-in-service, perform a detailed visual inspection of the angle brackets attaching the hinge ribs at Stations 27.582 and 29.582 for cracks, and a detailed visual inspection of the fasteners attaching the reinforcing plates for security, in accordance with paragraph 2.A. of British Aerospace Service Bulletin ATP 55-3, Revision 4, dated June 28, 1990.
(1) If cracking or local distortion is found on the angles or doubling plate flanges on the front face of the rudder spar, prior to further flight, remove the bolts and doubling plates, and perform a detailed visual inspection in accordance with paragraph 2.B. of the service bulletin.
(2) All items found cracked and all rivets found distorted or insecure must be replaced with a serviceable part prior to further flight, in accordance with paragraph 2.C of the service bulletin.
(b) For airplanes with rudders fitted with Modification 10165A during production: Prior to the accumulation of 6,250 hours time-in-service, or within 30 days after May 28, 1991 (the effective date of AD 91-09-13, Amendment 39-6979), whichever occurs later, and thereafter at intervals not to exceed 500hours time-in-service, perform a detailed visual inspection of the angle brackets attaching the hinge ribs at Stations 27.582 and 29.582 for cracks, and a detailed visual inspection of the fasteners attaching the reinforcing plates for security, in accordance with paragraph 2.A. of British Aerospace Service Bulletin ATP 55-3, Revision 4, dated June 28, 1990.
(1) If cracking or local distortion is found on the angles or doubling plate flanges on the front face of the rudder spar, prior to further flight, remove the bolts and doubling plates, and perform a detailed visual inspection in accordance with paragraph 2.B. of the service bulletin.
(2) All items found cracked and all rivets found distorted or insecure must be replaced with a serviceable part prior to further flight in accordance with paragraph 2.C. of the service bulletin.
(c) For airplanes with rudders fitted with Modification 10165A in accordance with British Aerospace Service Bulletin ATP-55-4, or by previous repair or replacement action: Prior to the accumulation of 500 hours time-in-service following installation, or within 30 days after May 28, 1991 (the effective date of AD 91-09-13, Amendment 39-6979), whichever occurs later, and thereafter at intervals not to exceed 500 hours time-in-service, perform a detailed visual inspection of the angle brackets attaching the hinge ribs at Stations 27.582 and 29.582 for cracks, and a detailed visual inspection of the fasteners attaching the reinforcing plates for security, in accordance with paragraph 2.A. of British Aerospace Service Bulletin ATP 55-3, Revision 4, dated June 28, 1990.
(1) If cracking or local distortion is found on the angles or doubling plate flanges on the front face of the rudder spar, prior to further flight, remove the bolts and doubling plates, and perform a detailed visual inspection in accordance with paragraph 2.B. of the service bulletin.
(2) All items found cracked and all rivets found distorted or insecure must be replaced with a serviceable part prior to further flight in accordance with paragraph 2.C. of the service bulletin.
(d) The installation of Modification 10170A, which includes strengthening the rudder lower hinge ribs at Stations 27.582, 29.582, and 24.82, in accordance with British Aerospace Service Bulletin ATP 55-5, dated November 30, 1990, or Revision 1, dated January 3, 1991, constitutes terminating action for the repetitive inspections required by paragraphs (a), (b), and (c) of this AD.
(e) An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate.
NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Standardization Branch, ANM-113.
(f) Special flight permits may be issuedin accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.
(g) The inspection and replacement requirements shall be done in accordance with British Aerospace Service Bulletins ATP 55-3, Revision 4, dated June 28, 1990. The optional modification shall be done in accordance with either British Aerospace Service Bulletin ATP 55-5, dated November 30, 1990, or British Aerospace Service Bulletin ATP 55-5, Revision 1, dated January 3, 1991. 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, PLC, Librarian for Service Bulletins, P.O. Box 17414, Dulles International Airport, Washington, D.C. 20041-0414. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington; or at the Office of the Federal Register, 1100 L Street N.W., Room 8401, Washington, D.C.
(h) Airworthiness Directive 91-25-07, supersedes AD 91-09-13, Amendment 39-6979.
(i) This amendment (39-8108, AD 91-25-07) becomes effective on January 9, 1992.