84-07-05 DeHAVILLAND: Amendment 39-4844. Applies to all Models DHC-2 MK. I (including L-20A, YL-20, U-6 and U-6A), MK. II, and MK. III airplanes certificated in any category.
Compliance: Required as indicated, unless already accomplished.
To prevent failure of center hinge/balance arm brackets, (aluminum castings) P/N C2-WA-126A (RH) and P/N C2-WA-125A (LH), accomplish the following:
(a) Within the next 100 hours time-in-service or two months, whichever occurs first, after the effective date of this AD, unless already accomplished within the last 400 hours time-in- service, or ten months, and at each 500 hours time-in-service or twelve months thereafter, whichever occurs first, accomplish the following:
(1) Visually inspect the left and right aileron center hinge/balance arm brackets as described in "ACCOMPLISHMENT INSTRUCTIONS" in DeHavilland Service Bulletin (SB) No. 2/37 Revision A, dated December 9, 1983.
(2) If a center hinge bracket is found withsix attachment rivet holes in the spigot, replace the balance arm assembly and the center hinge bracket within 500 hours time-in- service or twelve months, whichever occurs first after the inspection, with a new balance arm assembly in a 2-rivet attachment configuration with either a new cast bracket, P/N C2-WA-125A(LH) or P/N C2-WA-126A(RH), or a new machined bracket, P/N C2-WA-161(LH) or P/N C2-WA-162(RH).
(b) If cracks are found, replace the part before further flight with a new part of-the same part number, or with new machined brackets, P/N C2-WA-161(LH) or P/N C2-WA- 162(RH), in accordance with the procedure described in "REPLACEMENT" in DeHavilland SB No. 2/37.
(c) Cast parts installed as replacements must be reinspected with the procedure in paragraph (a).
(d) The repetitive inspections of paragraph (a) of this AD are no longer required when DeHavilland Modification Kit No. 2/1536 is installed.
(e) The airplane may be flown in accordance with FAR 21.197 to alocation where the requirements of this AD may be accomplished.
(f) 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.
This amendment becomes effective on April 18, 1984.