91-03-16 BOEING: Amendment 39-6875. Docket No. 90-NM-175-AD. \n\n\tApplicability: Model 747-400 series airplanes, as listed in Boeing Alert Service Bulletin 747-25A2862, Revision 1, dated December 13, 1990, certificated in any category. \n\n\tCompliance: Required within the next 9 months after the effective date of this AD, unless previously accomplished. \n\n\tTo prevent smoking material from dropping behind the sidewall lining at the second observers station, accomplish the following: \n\n\tA.\tInstall a housing on the outboard side of the second observer's ashtray in accordance with Boeing Alert Service Bulletin 747-25A2862, Revision 1, dated December 13, 1990. \n\n\tB.\tAn alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. \n\n\tNOTE: The request should be submitted directly to the Manager, SeattleACO, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence to the Seattle ACO. \n\n\tC.\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD. \n\n\tAll persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington. \n\n\tThis amendment (39-6875, AD 91-03-16) becomes effective on March 4, 1991.