93-08-19 BRITISH AEROSPACE: Amendment 39-8567. Docket 93-NM-49-AD.
Applicability: All Model ATP series airplanes, certificated in any category.
Compliance: Required as indicated, unless accomplished previously.
To prevent multiple engine power loss during flight in freezing precipitation, accomplish the following:
(a) Within 16 days after the effective date of this AD, measure the electrical resistance of the electrical bonding between certain components in engine nacelle module 3 and the airframe earth on the left and right engine nacelles in accordance with Jetstream Aircraft, Ltd., Service Bulletin ATP-24-55, Revision 1, dated April 24, 1993.
(1) If the electrical resistance measures less than 3 ohms, prior to further flight, reassemble the throttle stepper motor controller installation, overseal all bolts, and perform an operational test of the standby power lever controls in accordance with the service bulletin.
(2) If the electrical resistance measures 3 or more ohms, prior to further flight, accomplish the actions described in paragraphs 2.A.4) through 2.A.14) of the Accomplishment Instructions of the service bulletin, as applicable.
(b) 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.
(c) 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.
(d) The measurement,modification, oversealing, and operational test shall be done in accordance with Jetstream Aircraft, Ltd., Service Bulletin ATP-24-55, Revision 1, dated April 24, 1993. 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.
(e) This amendment becomes effective on May 6, 1993.