76-11-05 R1 BOEING: Amendment 39-2630, as amended by Amendments 39-2667 and 39- 2708, is further amended by Amendment 39-6234. \n\n\tApplicability: Boeing Model 737 series airplanes, line number 001 through 491, certificated in any categories. \n\tCompliance: Required as indicated, unless previously accomplished. \n\tTo prevent hazardous flutter of the elevator/horizontal stabilizer, accomplish the following: \n\tA.\tUpon receipt of a pilot report of vibration in the longitudinal control system, prior to further flight, accomplish the inspection required by paragraph C., below. If the relative deflections are less than specified in paragraph C., below, prior to further flight, investigate for the cause of vibration in accordance with existing procedures. \n\tB.\tIn addition to paragraph A., above, within the next 300 hours time-in-service after the effective date of this AD, unless accomplished within the last 700 hours time-in-service, and at intervals thereafter not to exceed 1,000 hours time-in-service, conduct the inspection required by paragraph C., below. \n\tC.\tInspect for excessive deflection of the elevator tab, right and left hand, in accordance with the inspection procedures specified in Section III, Part I, paragraphs C. and D., of Boeing Alert Service Bulletin 737-55A1020, Revision 1, dated August 20, 1976; Revision 2, dated February 11, 1977; or Revision 3, dated December 22, 1988. If the elevator tab-to-elevator relative deflection exceeds 1/10 inch, prior to further flight, modify the elevator in accordance with paragraph D., below. \n\tD.\tInstallation of one of the modifications specified in Boeing Alert Service Bulletin 737-55A1020, Revision 1, dated August 20, 1976; Revision 2, dated February 11, 1977, or Revision 3, dated December 22, 1988; Section III, Part II, including installation of the bolt retainer clips or the preventive modification specified in Boeing Service Bulletin 737-55-1022, Section III, Part II, dated April 15, 1987, is considered terminating action for the inspection requirements of this AD.\n \tE.\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, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region. \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, Seattle Aircraft Certification Office. \n\tF.\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes having cracked parts to a base in order to comply with the requirements of this AD. The application for a special flight permit must contain a limitation stating that the airplane must be operated within limits specified in Boeing Operation Manual Bulletin 76-2. \n\tAll persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or at the Seattle Aircraft Certification Office, FAA, Northwest Mountain Region, 9010 East Marginal Way South, Seattle, Washington. \n\n\tThis AD revises AD 76-11-05 (Amendment 39-2630) as amended by Amendments 39- 2667 and 39-2708. \n\tThis amendment (39-6234, AD 76-11-05 R1) becomes effective on July 24, 1989.