74-20-02: Pitot Static Tubing

74-20-02 BOEING: Amendment 39-1969. Applies to all Model 737 airplanes, certificated in all categories, listed in Boeing Service Bulletin 737-34-1031 dated March 1, 1974, or later FAA approved revisions. \n\tTo prevent erroneous information from being displayed on the pitot-static flight instruments: \n\tWithin the next 3500 hours time in service after the effective date of this AD, modify the pitot static tubing to include a vertical rise just inboard of each pitot-static probe in accordance with Boeing Service Bulletin 737-34-1031, dated March 1, 1974, or later FAA approved revisions, or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA, Northwest Region. \n\tThe 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). \n\tAll 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. The documents may be examined at FAA Northwest Region, 9010 East Marginal Way, Seattle, Washington. \n\n\tThis amendment becomes effective 30 days after September 25, 1974.