AD 77-13-15

77-13-15 BOEING: Amendment 39-2944 as amended by Amendment 39-2989. Applies to all Model 727 series airplanes listed in Boeing Service Bulletin No. 727-53-134, Revision 3, or later FAA approved revisions, and certificated in all categories. Compliance required as indicated. To detect cracking in the Body Station 910 floor beam, accomplish the following: A. Within the next 1000 pressurization cycles for airplanes with more than 20,000 pressurization cycles on the effective date of this AD, or prior to the accumulation of 21,000 pressurization cycles for airplanes with less than 20,000 pressurization cycles on the effective date of this AD, inspect the lower flanges of the B.S. 910 floor beam for cracks per paragraph B below. If inspected within the last 1000 pressurization cycles prior to the effective date of this AD per paragraph B.2, reinspect in accordance with paragraph E. Beams found cracked are to be repaired per paragraph C. B. Inspect the B.S. 910 floor beam inaccordance with one of the following: 1. Low frequency eddy current inspection procedures of Figure 3 of Boeing Service Bulletin No. 727-53-134, Revision 3 or later FAA approved revisions. 2. Eddy current or dye penetrant inspection procedures of Figure 2 of Boeing Service Bulletin No. 727-53-134, Revision 3, or later FAA approved revisions. 3. A manner approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. C. If cracks are detected in the beam, repair in accordance with Boeing Service Bulletin No. 727-53-134, Revision 3, or later FAA approved revisions, or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region, prior to further flight except that the airplane may be flown unpressurized in accordance with FAR 21.197 to a base where the repair can be accomplished. D. Airplanes which have had the straps or repair doubler installed in accordance with Boeing Alert Service Bulletin No. 727-53-124, or FAA approved equivalent, must be inspected once in accordance with paragraphs B.2 or B.3 of this AD within 3000 pressurization cycles from the effective date of this AD, in lieu of compliance with the compliance times specified in paragraphs A and E, unless already accomplished. Beams found cracked are to be repaired in accordance with paragraph C. E. Repeat the inspections per paragraph B.1 at intervals not to exceed 1000 pressurization cycles or per paragraph B.2 at intervals not to exceed 2000 pressurization cycles. F. Terminating action of this AD consists of inspection per paragraphs B.2 or B.3 and installation of the preventive modification straps or repair doubler in accordance with Boeing Alert Service Bulletin No. 727-53-124, Revision 1, or equivalent approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. G. For the purpose of complying with this AD, the number of pressurization cycles may be considered to be identical to the number of landings.H. Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA Northwest Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for that operator. The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer, may obtain copies upon request to Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98124. These documents may also be examined at FAA Northwest Region, 9010 East Marginal Way South, Seattle, Washington 98108.

Amendment 39-2944 became effective August 5, 1977. This amendment 39-2989 becomes effective August 1, 1977.