89-14-10 McDONNELL DOUGLAS: Amendment 39-6253. \n\n\tApplicability: Model DC-9-10, -20, -30, -40, -50, and C-9 series airplanes, certificated in any category. \n\n\tCompliance: Required as indicated, unless previously accomplished. \n\n\tTo prevent premature fatigue failure of engine mount cone bolts, accomplish the following: \n\n\tA.\tWithin 90 days after the effective date of this AD, determine if forward engine mount cone bolts, Barry Controls part number R18210-2, serial numbers 15B8021 through 15B8329, 15B8332 through 15B8382, 15B8396 through 15B8399; or aft engine mount cone bolt, Barry Controls part number R18211-2, serial numbers 15B5242 through 15B5320; are installed. \n\n\tNOTE: This determination may be accomplished by conducting either a thorough review of receiving inventory and/or maintenance records, or a visual inspection of each installed cone bolt. \n\n\tB.\tIf any of the cone bolts identified in paragraph A., above, are installed, or if a determination of the installation of discrepant bolts cannot be made, remove the cone bolt(s) and replace it with a properly heat-treated cone bolt within 2,000 flight hours after installation or 15 days after discovery, whichever occurs later, in accordance with McDonnell Douglas Service Bulletin 71-46, dated April 24, 1989. \n\n\tC.\tAn 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. \n\n\tNOTE: The 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. \n\n\tD.\tSpecial 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. \n\n\tAll persons affected by this directive whohave 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, Publication and Training, C1-750 (54-60). These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or the Los Angeles Aircraft Certification Office, 3229 East Spring Street, Long Beach, California. \n\n\tThis amendment (39-6253, AD 89-14-10) becomes effective on July 17, 1989.