89-24-06 R1: Elevator Quadrant

89-24-06 R1 BOEING OF CANADA, LTD., DEHAVILLAND: Amendment 39-6670. Docket No. 89-CE- 29-AD. Applicability: Models DHC-6-1, DHC-6-100, DHC-6-200, and DHC-6-300, (all serial numbers) airplanes, certificated in any category. Compliance: Required as indicated in the body of the AD, unless already accomplished per AD 89-24- 06. To prevent loss of elevator control, accomplish the following: (a) Within the next 25 hours time-in-service (TIS) after the effective date of this AD, and thereafter at intervals not to exceed 200 hours TIS, accomplish the following: Note 1: When a parked Model DHC-6 airplane has been subjected to wind gusts of 35 mph or greater (including helicopter or jet blasts), new damage may occur to the elevator control system. (1) Visually inspect the elevator quadrant, Part Number (P/N) C6CFM 1138-27 (Pre Mod 6/1394), or P/N C6CFM 1450-27 (Post Mod 6/1394 PCI S/N 331, Pre Mod 6/1678), or P/N C6CFM 1450-29 (Post Mod 6/1678, PCI S/N 602), for distortion by viewing the quadrant from the forward or aft direction to detect warping or buckling, and by looking for score marks on the quadrant topside face due to constant rubbing against the side of the cable guard. (2) If the elevator quadrant is found distorted, prior to further flight replace it with a serviceable part and reinspect the quadrant at 200 hours TIS intervals thereafter. (3) If the elevator quadrant is found distorted, prior to further flight visually inspect the elevator quadrant mounting support bracket P/N C6CFM 1142-1 for cracks using a strong light and minimum four power magnifying glass. Note 2: Pay particular attention to the outer and inner surfaces of two lugs of the bracket. (4) If the elevator quadrant support bracket is found cracked, prior to further flight replace it with a serviceable part. (b) Airplanes may be flown in accordance with FAR 21.197 to a location where this AD may be accomplished. (c) An alternatemeans of compliance or adjustment of the initial or repetitive compliance times which provides an equivalent level of safety may be approved by the Manager, New York Aircraft Certification Office, FAA, New England Region, Valley Stream, New York 11581. Note 3: The request should be forwarded through an FAA Maintenance Inspector who may add comments and then send it to the Manager, New York Aircraft Certification Office. All persons affected by this directive may examine the information pertaining to the issuance of this AD at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 East 12th Street, Kansas City, Missouri 64106. This AD revises AD 89-24-06, Amendment 39-6387. This amendment (39-6670, AD 89-24-06 R1) becomes effective on September 13, 1990.