AD 91-04-05

91-04-05 BRITISH AEROSPACE: Amendment 39-6889. Docket No. 90-NM-235-AD. Applicability: Model ATP series airplanes, Serial Numbers 2002 through 2018, inclusive, certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To prevent the loss of all DC electrical power, accomplish the following:

A. Within 60 days after the effective date of this AD, disconnect the stall warning contoured airframe heaters from the essential 28V DC busbars and reconnect them to the nonessential busbars, in accordance with the Accomplishment Instructions in British Aerospace Service Bulletin ATP-27-18, Revision 1, dated January 31, 1990.

B. An alternate means 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 submitted directly to the Manager, Standardization Branch, ANM-113, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence to the Manager, Standardization Branch, ANM-113.

C. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.

All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to British Aerospace, PLC, Librarian for Service Bulletins, Dulles International Airport, Washington, D.C. 20041-0414. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue, S.W., Renton, Washington 98055-4056.

This amendment (39-6889, AD 91-04-05) becomes effective on March 18, 1991.