AD 83-04-05

83-04-05 DeHAVILLAND: Amendment 39-4568. Applies to Model DHC-3 (U-1A) airplanes certificated in any category.

COMPLIANCE: As prescribed in the body of the AD.

To prevent loss of primary flight controls due to fracture of the control column lower weld assembly, accomplish the following:

a. Within the next 25 hours time-in-service after the effective date of this AD, unless already accomplished within the last 75 hours, and at each 100 hours time-in-service thereafter, visually inspect the control column lower weld assembly, P/N C3CF 39-15 or C3CF 39-13 for cracks in accordance with the Accomplishment Section of DeHavilland Service Bulletin S/B No. 3/39 dated October 1, 1982.

b. If no cracks are found, return the airplane to service and repeat the inspections required by paragraph a of this AD.

c. If cracks are found in control column lower assembly P/N C3CF 39-13, replace the assembly prior to further flight with a serviceable assembly P/N C3CF 39-15 or P/N C3CF 39-21 (Modification 3/930) as specified in the Replacement Section of said Service Bulletin.

d. If cracks longer than 1 inch are found in control column lower assembly P/N C3CF 39-15, repair or replace the assembly prior to further flight as instructed in the Accomplishment Instructions Section of said Service Bulletin.

e. If cracks 1 inch or less in length are found in control column lower assembly P/N C3CF 39-15, repair or replacement may be delayed for a period of 150 hours time-in-service provided the inspection prescribed in paragraph a above is accomplished at 25-hour intervals.

f. The repetitive inspections of paragraph a of this AD may be discontinued when control column lower assembly P/N C3CF 39-21 (Modification 3/930) is installed.

g. The airplane may be flown in accordance with Federal Aviation Regulation 21.197 to a location where this AD can be accomplished.

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

This amendment becomes effective on March 1, 1983.