AD 84-20-07 ACTIVE

84-20-07 DeHAVILLAND: Amendment 39-4929. Applies to Models DHC-2 MK I (L- 20A, YL-20, U-6, and U-6A), MK II (S/N 80) Beaver, and MK III Turbo Beaver series airplanes, certificated in any category.

Compliance: Required as indicated, unless already accomplished.

NOTE: The compliance dates specified in paragraphs (b) and (c) below were established by superseded AD 83-05-03, Amendment 39-4576, effective March 7, 1983.

To prevent failure of the wing lift strut, accomplish the following:

(a) For ex-military airplanes with wing lift strut assemblies C2W545A/C2W546A and for airplanes fitted with ex-military strut assemblies C2W545A/C2W546A, comply with paragraphs (1) and (2) below within the next 100 hours time-in-service after the effective date of this AD, unless already accomplished within the last 400 hours time-in-service, and thereafter at intervals not to exceed 500 hours time-in-service from the last inspection.

(1) Detach each wing lift strut assembly from the attachment fitting on the wing. Ensure that each radius is smooth and blends smoothly into the lug without machine marks or nicks. Using a dye-penetrant method with at least a 10-power glass or an FAA approved equivalent method, inspect the lift strut upper fitting for cracks with particular attention given to the 1/8-inch radius junction of the lug to the attachment flanges.

(2) If a crack, mark, or nick is found in the radius, replace the lift strut assembly before further flight with unused strut assemblies C2W1103A and C2W1104A, or with C2W1115-1 and C2W1115-2 for the MK I and MK III airplanes, and only with C2W1147 and C2W1148 strut assemblies for the MK II (S/N 80) airplane.

(b) For MK I airplanes with wing lift strut assemblies C2W545A/C2W546A, comply on or before July 15, 1983, unless already accomplished, with the requirements of the "COMPLIANCE" Section in DeHavilland Service Bulletin No. 2/34, Revision A, dated May 13, 1983.

(c) For MK I airplanes with wing lift strut assemblies C2W469A/C2W470A, 2W473A/C2W474A and C2W685A/C2W686A, comply on or before January 1, 1984, unless already accomplished, with the requirements of the "COMPLIANCE" Section in DeHavilland Service Bulletin No. 2/34, Revision A, dated May 13, 1983.

(d) For the MK II (S/N 80) airplane within 30 days after application for U.S. Registry, replace the earlier strut assemblies C2W573 and C2W574, unless already accomplished, with strut assemblies C2W1147 and C2W1148.

(e) For MK I and MK II (S/N 80) airplanes, comply as follows with the wing strut assembly retirement times in DeHavilland Service Bulletin No. 2/3, reissued May 13, 1983.

(1) For aircraft engaged in normal operations at maximum gross weight of 5100 lb., comply with paragraphs 2.1 and 2.2 of the Service Bulletin.

(2) For aircraft engaged in "special-purpose operations" at maximum gross weight of 5100 lb., comply with paragraphs 3.1 and 3.2 of the Service Bulletin.

(3) For aircraft engaged in operations at gross weight in excess of 5100 lb., comply with paragraphs 4.1, 4.2, and 4.3 of the Service Bulletin.

(f) For MK III airplanes, comply as follows with the wing strut assembly retirement times in DeHavilland Service Bulletin No. TB/9, reissued May 14, 1982.

(1) For airplanes engaged in normal operations at maximum gross weight of 5100 lb. , or 5370 lb. with tip tanks full, comply with paragraphs 2.1 and 2.2 of the Service Bulletin.

(2) For airplanes engaged in "special-purpose low level operations" at maximum gross weight of 5100 lb., or 5370 lb. with tip tanks full, comply with paragraphs 3.1 and 3.2 of the Service Bulletin.

(g) Replace modified or repaired strut assemblies identified in paragraphs 5.1 and 5.2 of Service Bulletin No. 2/3, reissued May 13, 1983, in accordance with the times prescribed therein.

(h) Whenever new wing strut assemblies are installed, the following new attachment bolts must be used:

AN180C-26 orAN180-26
Bolt-strut, lower attachment
C2W497
Bolt-strut, upper attachment

(i) A special flight permit may be issued in accordance with FAR 21.197 to operate the airplane to a location where the requirements of this AD may be accomplished.

(j) An equivalent method of compliance with this AD may be used if approved by the Manager, New York Aircraft Certification Office, ANE-170, 181 South Franklin Avenue, Room 202, Valley Stream, New York 11581; telephone (516) 791-6680.

This AD supersedes AD 83-05-03, Amendment 39-4576.

This amendment becomes effective on October 12, 1984.