57-06-02 MARTIN: Applies to All Models 202, 202A and 404 Aircraft.
Compliance required as indicated.
As a result of a number of failures in service, the engine mount attaching studs should be replaced as indicated below:
1. Replace the engine mount studs with approved studs whenever the Quick Engine Change unit is removed for major overhaul, but at intervals not exceeding 1,600 hours flight time. Both the stud and engine mount installation should be made with care since misalinement and/or improper torque could cause failure of the stud in service.
(Installation techniques are included in Martin Service Instruction Letter 404-50.)
2. If the engine mount studs are replaced with approved through-bolt installations, the replacement program of item 1 is not applicable, and this Airworthiness Directive no longer applies.
3. Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and ManufacturingBranch, FAA Eastern Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for such operator.
(Martin Service Instruction Letter 202/202A of October 1, 1956, covers this same subject.)
This supersedes AD 51-29-04.
Revised January 11, 1963.