AD 91-09-51

91-09-51 BOEING OF CANADA, LTD., DE HAVILLAND DIVISION: Amendment 39- 7026. Docket No. 91-NM-101-AD. Final Rule of Telegraphic AD T91-09-51.

Applicability: de Havilland Model DHC-8-100 and -300 series airplanes, certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To prevent an oxygen-fed, in-flight fire under the flight compartment floor, accomplish the following:

(a) Within 24 hours after the effective date of this amendment, perform a visual inspection of the flight crew oxygen lines and adjacent electrical feeder cables in accordance with Boeing of Canada de Havilland Division Alert Service Bulletin A8-35-5, Revision A, dated April 5, 1991.

(b) If evidence of chafing is found in the crew oxygen lines or adjacent electrical feeder cables, prior to further flight, repair or replace damaged lines or cables, in accordance with Boeing of Canada de Havilland Division Alert Service Bulletin A8-35-5, Revision A, dated April 5, 1991.

(c) 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, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate.

NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Standardization Branch, ANM-113.

(d) 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.

The inspection and repair or replacement requirements shall be done in accordance with Boeing of Canada de Havilland Division Alert Service Bulletin A8-35-5, Revision A, dated April 5, 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 of Canada, Ltd., de Havilland Division, Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. Copies may be inspected at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington; at the FAA, New England Region, New York Aircraft Certification Office, 181 South Franklin Avenue, Room 202, Valley Stream, New York; or at the Office of the Federal Register, 1100 L Street N.W., Room 8401, Washington, D.C.

This amendment (39-7026, AD 91-09-51) becomes effective on July 29, 1991, as to all persons, except those persons to whom it was made immediately effective by telegraphic AD T91-09-51, issued April 25, 1991, which contained this amendment.