AD 92-02-06

92-02-06 BOEING: Amendment 39-8142. Docket No. 91-NM-262-AD.

Applicability: Model 747-400 series airplanes, listed in Boeing Alert Service Bulletin 747-35A2075, Revision 1, dated September 19, 1991, certificated in any category.

Compliance: Required within the next 30 days after the effective date of this AD, unless accomplished previously.

To prevent pilot incapacitation during an emergency situation requiring supplemental oxygen to the flight crew, accomplish the following:

(a) Inspect the captain's and first officer's oxygen hoses below the oxygen mask stowage boxes in accordance with Boeing Alert Service Bulletin 747-35A2075, Revision 1, dated September 19, 1991. Replace damaged or short hoses before further flight, in accordance with the service bulletin.

(b) An alternative method 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 CertificationOffice (ACO), FAA, Transport Airplane Directorate. The request shall be forwarded through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Seattle ACO.

(c) Special 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.

(d) The inspection and replacement requirements of this AD shall be done in accordance with Boeing Alert Service Bulletin 747-35A2075, Revision 1, dated September 19, 1991. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington; or at the Office of the Federal Register, 1100 L Street NW., Room 8401, Washington, D.C.(e) This amendment (39-8142, AD 92-02-06) becomes effective on January 24, 1992.