AD 89-23-15

89-23-15 BOEING OF CANADA, LTD., DE HAVILLAND DIVISION: Amendment 39- 6384. Docket No. 89-NM-80-AD.

Applicability: Model DHC-8-100 series airplanes, Serial Numbers 1 through 91, certificated in any category.

Compliance: Required within the next 400 hours time-in-service after the effective date of this AD, unless previously accomplished.

To prevent unwanted propeller feathering due to inadvertent activation of the alternate feather switches, accomplish the following:

A. Modify the alternate feather system, in accordance with the Accomplishment Instructions of Boeing of Canada, Ltd., de Havilland Division, Service Bulletin No. 8-61-10, Revision A, dated August 5, 1988.

B. An 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, New York Aircraft Certification Office, FAA, New England Region.

NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who will either concur or comment and then send it to the Manager, New York Aircraft Certification Office.

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.

All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Boeing of Canada, Ltd., de Havilland Division, Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or New York Aircraft Certification Office, Engine and Propeller Directorate, Aircraft Certification Service, FAA, 181 South Franklin Avenue, Room 202, Valley Stream, New York 11581.

This amendment (39-6384, AD 89-23-15) becomes effective on December 11, 1989.