AD 88-12-05

88-12-05 MCDONNELL DOUGLAS: Amendment 39-5935. Applies to Models DC-9-30, DC-9-41, DC-9-51, DC-9-81, DC-9-82, and DC-9-83 series airplanes; equipped with Hydro-Aire Auto Brake Control Units, Part Numbers 42-409, 42-409-1, 42-639, 42-639-1, 42-809, or 42-839; certificated in any category.

Compliance required as indicated, unless previously accomplished.

To eliminate inadvertent disarming of the Auto Brake System following exposure to momentary electrical power interruptions or transients, accomplish the following:

A. Within 12 months after the effective date of this airworthiness directive (AD), modify the Hydro-Aire Auto Brake Control Units, Part Numbers 42-409, 42-409-1, 42-639, 42-639-1, 42-809 or 42-839, in accordance with the Accomplishment Instructions of McDonnell Douglas DC-9 Service Bulletin 32-216, dated September 24, 1987.

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, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region.

NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who may add any comments and then send it to the Los Angeles Aircraft Certification Office.

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 information from the manufacturer may obtain copies upon request to McDonnell Douglas Corporation, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Director of Publications, C1-L00 (54-60). These documents may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Los Angles Aircraft Certification Office, 4344 Donald Douglas Drive, Long Beach, California.This Amendment, 39-5935, becomes effective July 1, 1988.