AD 90-25-04

90-25-04 McDONNELL DOUGLAS: Amendment 39-6817. Docket No. 90-NM-71-AD.

Applicability: Models DC-9-81, -82, -83 and -87 (MD-81, -82, -83, and -87) series airplanes, and Model MD-88 series airplanes, certificated in any category.

Compliance: Required as indicated, unless accomplished since December 21, 1989.

To prevent the engine from departing the aircraft during a hard landing, in the event of a sudden engine seizure, or during flight when high velocity vertical gust is encountered, accomplish the following:

A. Within 30 days after the effective date of this AD, accomplish the following:

1. Perform one of the following inspections:

a. Perform a one-time visual inspection of both the left and right engine forward mount cone bolts for the correct part number, in accordance with McDonnell Douglas MD-80 Alert Service Bulletin A71-49, Revision 2, dated November 4, 1990 (from hereon referred to as the Service Bulletin). If the part number of the cone bolt is other than "Barry" Part Number K2219-9SA3 or McDonnell Douglas Part Number 7938004-503, prior to further flight, remove and replace the bolt with a "Barry" Part Number K2219-9SA3 or McDonnell Douglas Part Number 7938004-503 cone bolt; or

b. Perform a one-time ultrasonic inspection of both the left and right engine forward mount cone bolts in accordance with the Service Bulletin. If the part shows an indication of shear section cut-out, remove and replace the bolt with a "Barry" Part Number K2219-9SA3 or McDonnell Douglas Part Number 7938004-503 cone bolt.

2. Incorporate a revision into the FAA-approved maintenance inspection program which provides for a visual or ultrasonic inspection of the engine forward mount cone bolts for "Barry" Part Number K2219-9SA3, or McDonnell Douglas Part Number 7938004-503, at each engine change and, if incorrect bolts are found, replace with "Barry" Part Number K2219-9SA3 or McDonnell Douglas Part Number 7938004-503 bolts before eachengine installation.

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 (ACO), FAA, Transport Airplane Directorate.

NOTE: The request should be submitted directly to the Manager, Los Angeles ACO, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence to the Los Angeles ACO.

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: Business Unit Manager of Publications, C1-HCW (54-60). These documentsmay be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington, or the Los Angeles Aircraft Certification Office, 3229 East Spring Street, Long Beach, California.

This amendment (39-6817, AD 90-25-04) becomes effective January 2, 1991.