AD 90-04-05

90-04-05 MCDONNELL DOUGLAS: Amendment 39-6504. Docket No. 89-NM-143-AD.

Applicability: Model DC-9-80 and MD-88 series airplanes, certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To prevent takeoff of an airplane while in an unsafe configuration for takeoff, due to deactivation of the takeoff warning system by the flight crew to eliminate nuisance warnings of the takeoff warning system during single-engine taxi operation, accomplish the following:

A. Within 12 months after the effective date of this AD, rewire the takeoff warning system throttle lever switches to place them in series, rather than in parallel, in a manner approved by the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region, or in accordance with the Accomplishment Instructions of McDonnell Douglas Service Bulletin 31-34, dated December 20, 1989.

B. An alternate means of compliance or adjustment of the compliancetime, 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: This request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who will either concur or comment and then send it to the Manager, Los Angeles Aircraft Certification Office, FAA, Northwest Mountain Region.

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 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, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or Los Angeles Aircraft Certification Office, 3229 East Spring Street, Long Beach, California 90806.

This amendment (39-6504, AD 90-04-05) becomes effective on March 8, 1990.