AD 91-18-20

91-18-20 BOEING OF CANADA, LTD., DE HAVILLAND DIVISION: Amendment 39- 8024. Docket No. 91-NM-41-AD.

Applicability: Model DHC-7 series airplanes, Serial Numbers 1 through 27, certificated in any category.

Compliance: Required, as indicated, unless previously accomplished.

To prevent a possible failure of the main landing gear (MLG), accomplish the following:

(a) Within one year after the effective date of this AD, remove each MLG upper drag strut assembly from the airplane and perform a non-destructive test in accordance with the Accomplishment Instructions, paragraphs 2.D.(1) through (3), of Menasco Canada, Ltd., Service Bulletin No. 32-18, Revision 1, dated June 5, 1980.

(1) If there is no evidence of cracking, prior to further flight, overhaul the assembly in accordance with the Accomplishment Instructions, paragraph 2.D.(4), of the service bulletin.

(2) If cracking is evident, prior to further flight, replace the assembly with a serviceable part, in accordance with the service bulletin.

NOTE: The Menasco Canada, Ltd., Service Bulletin references Menasco Mfg. Component Maintenance Manual 32-10-16, dated September 1, 1976, as an additional source of service information for performing overhaul procedures.

NOTE: In the referenced Menasco Component Maintenance Manual, procedures are found only for "Repair." For this application, repair is equivalent to overhaul.

(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, New York Aircraft Certification Office (ACO), ANE-170, FAA, New England Region.

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.

(c) Special flight permits may be issued in accordance with FARs 21.197 and 21.199 to operate airplanes to a base in order tocomply with the requirements of this AD.

(d) The inspection, overhaul, and replacement requirements shall be done in accordance with Menasco Canada, Ltd., Service Bulletin No. 32-18, Revision 1, dated June 5, 1980. 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, 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 (39-8024, AD 91-18-20) becomes effective on October 15, 1991.