AD 81-20-04 R1

81-20-04 R1 BOEING: Amendment 39-4225 as amended by Amendment 39-4250. Applies to Boeing Model 727-200 series and 737 airplanes, certificated in all categories, using the following Hamilton Standard electronic pressurization controllers that have not been previously modified to HS reference number P57:

HS Part Number Boeing Part Number 710204-7 10-61209-13 710204-8 10-61209-14 761260-7 10-61209-19 761260-8 10-61209-18

To prevent inflight fires, on or before May 12, 1982, accomplish the following, unless already accomplished: Modify the Hamilton Standard pressurization controllers listed above in accordance with Boeing Service Bulletins 727-21 A96 and 737-21 A1064, published August 28, 1981, or later FAA approved revision, or in a manner approved by the Chief, Seattle Area Aircraft Certification Office. The Assurance of Serviceability testing described in Paragraph B(16) of Hamilton Standard Service Bulletin 21-88, Revision 1, dated October 13, 1981, may be used in lieu of the complete functional test specified in the Boeing Service Bulletins listed above.

The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received the above specified Alert Service Bulletin from the manufacturer may obtain copies upon request to Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98124, or it may also be examined at FAA Northwest Region, 9010 East Marginal Way South, Seattle, Washington 98108.

Amendment 39-4225 became effective October 13, 1981. This amendment 39-4250 becomes effective November 13, 1981.