AD 88-04-09

88-04-09 BOEING: Amendment 39-5854. Applies to Model 767 series airplanes, as listed in Boeing Service Bulletin 767-36-0021, dated September 17, 1987, certificated in any category. Compliance required within the next six months after the effective date of this AD, unless already accomplished.

To preclude engine or pneumatic system damage caused by failure of the pneumatic system 8th stage check valve, accomplish the following:

A. Within the next 6 months after the effective date of this AD, inspect the pneumatic system 8th stage check valves on both engines, in accordance with Boeing Service Bulletin 767-36-0021, dated September 17, 1987, or later FAA-approved revision, to determine if the serial numbers are among those listed in Hamilton Standard Service Bulletin 36-2056, dated June 29, 1987, or later FAA-approved revision, as requiring further inspection.

B. If any valve is identified by serial number as requiring further inspection, prior to further flight, remove the valve from the airplane, inspect the valve retention collar and, if necessary, modify the valve in accordance with the above mentioned service bulletins.

C. Valves not installed on an airplane must be inspected, and modified if necessary, in accordance with the above-mentioned service bulletins, prior to their installation on airplanes.

D. An alternate means of compliance or adjustment of the compliance time, which provide an acceptable level of safety, and which has the concurrence of an FAA Principal Maintenance Inspector, may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region.

E. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of the rework required by 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 the Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98124-2207. These documents may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington.

This amendment becomes effective April 5, 1988.