71-09-04 BOEING: Amdt. 39-1199. Applies to Model 727 airplanes listed in Boeing Service Bulletin 32-188, dated March 29, 1971, or later FAA approved revisions. \n\tCompliance required as indicated. \n\tTo detect cracking of the main landing gear actuator beam, accomplish the following: \n\tA.\tUnless already accomplished within the last 300 hours' time in service preceding the effective date of this AD, within the next 300 hours' time in service after the effective date of this AD or prior to the accumulation of 5300 hours' time in service, whichever occurs later, accomplish one of the following: \n\t\t1.\tVisually inspect the main landing gear actuator beam for any evidence of cracking in accordance with Boeing Service Bulletin 32-188, dated March 29, 1971, or later FAA approved revision, or an equivalent method approved by the Chief, Aircraft Engineering Division, FAA Western Region. Repeat the visual inspection at intervals not to exceed 600 hours' time in service, or \n\t\t2.\tUltrasonically inspect the main landing gear actuator beam for cracks in accordance with Boeing Service Bulletin 32-188, dated March 29, 1971, or later FAA approved revision, or an equivalent method approved by the Chief, Aircraft Engineering Division, FAA Western Region. Repeat the ultrasonic inspection at intervals not to exceed 1500 hours' time in service. \n\tB.\tIf cracks are found replace the beam with a serviceable beam. \n\tC.\tWhere records maintained by the operator are such as will permit a clear determination of the number of hours' time in service accumulated by the main landing gear actuator beam, P/N 65-17658-11, installed on the airplane, the inspection times prescribed by this AD may be applied to the beam rather than to the airplane. \n\tD.\tInspections prescribed by this AD do not apply to new replacement beams, P/N 65- 57153-3, or to P/N 65-17658-11 beam until 5300 hours' time in service is reached. \n\tE.\tAirplanes having cracked main landing gear actuator beams which require replacement under this AD may, in accordance with FAR 21.197, be flown with the landing gear extended to a base where the replacement can be accomplished. \n\tThis AD becomes effective May 28, 1971.