1AD/LYC/71 Amdt 1 - Pushrod - Inspection

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Lycoming Piston Engines

AD/LYC/71

Amdt 1

Pushrod - Inspection 3/81

Applicability: 0-235 series engines with S/Nos. L-12500-15 to L-20676-15 inclusive, all Lycoming remanufactured 0-235 series engines, regardless of S/No., shipped between 10 December 1976 and 8 November 1979, and all 0-235 series engines regardless of S/No., that had pushrods replaced between 10 December 1976, and 24 November 1980. This AD does not apply to engines incorporating eight pushrods identified by revision letter K or subsequent revision letter, or by Code T-T, -85, or the symbol # as described in SB No. 453A.

Requirement: Part 1 - Remove all eight pushrods and inspect for loose ball ends and evidence of bulging and splitting of the pushrod tubing. Measure the length of the pushrod assembly. The overall length shall not be less than 11-17/32 inches. If all these conditions are satisfactory, set valve clearances in accordance with Para. 8 of Lycoming SI Nos. 1388A dated 25 January 1980, and 1068A dated 1 September 1978. If any pushrod is found damaged or is less than the specified dimension noted above, replace with a serviceable part prior to further flight.

Part 2 - Measure and record valve tappet clearance in accordance with Lycoming SI Nos. 1388A and 1068A. If any valve clearance increases more than .015 inch since the last 25 hour inspection, remove the pushrod and inspect for damage and shortening in accordance with Item 1 above.

Compliance: Part 1 - Within 25 hours time in service after 31 March 1981 or before 14 April 1981, whichever occurs first.

Part 2 - Within 25 hours time in service after 31 March 1981 or before 14 April 1981 whichever occurs first and thereafter at intervals not exceeding 25 hours time in service.

Note: Engines complying with the initial issue of this Directive satisfy the requirements of this issue of the Directive.

Background: This Directive is raised in issue to reflect the following changes:

(a) Engines of Serial Numbers Listed in Lycoming SB No. 435A as exempt from compliance are now also affected.

(b) FAA Directive No. 80-25-02, Rev. 2 forms the basis of this Directive. Overseas reports show one recent fatal accident attributable to this problem and in excess of 80 reports of failed pushrods found in service. A number of local defects have also occurred.

Inspection of suspect pushrods is therefore necessary to prevent failure.

It is known that Ansett General Aviation Bankstown have the necessary tooling to inspect pushrods and reidentify as a -85 suffix to the part number.