AD 79-09-03

79-09-03 BOEING: Amendment 39-3454. Applies to all Model 747 series airplanes certificated in all categories. Compliance required within 500 hours time-in-service after the effective date of this AD unless already accomplished. To prevent takeoff with a takeoff aural warning system that would not indicate an unsafe takeoff condition, accomplish the following: Perform a one-time check of the aural warning system and, as necessary, adjust and re- check the aural warning activation switch, the auto-brake deactivation and auto-speedbrake retraction switches in accordance with Boeing Alert Service Bulletin 747-31A2056, Rev. 1, dated April 6, 1979, or later FAA approved revisions, or an equivalent method 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 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.

This amendment becomes effective May 10, 1979.