AD 75-04-06

75-04-06 BOEING: Amendment 39-2086. Applies to all Model 747 airplanes, certificated in all categories, listed in Boeing Service Bulletin 747-34-2058 dated January 31, 1974, or later FAA approved revisions. To prevent erroneous information from being displayed on flight instruments: Within the next 3,500 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 Work Package 1, 2, and 3 of Boeing Service Bulletin 747-34-2058, dated January 31, 1974, or later FAA approved revisions, or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. 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 these documents from the manufacturer may obtain copies upon request to the 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 98108. This amendment becomes effective March 10, 1975.