83-14-05 PIPER: Amendment 39-4685. Applies to Model PA-34-200 (S/N 34-7350343 through 34-7450220) airplanes and (S/N 34-7250001 through 34-7350342) airplanes that have exhaust systems installed in accordance with Piper Service Letter No. 673 and Piper Kit 760-764V, certificated in any category.
Compliance: Required as indicated unless already accomplished:
To prevent possible power loss or engine stoppage due to blockage of the muffler exit by a failed heat exchanger cone shaped baffle, accomplish the following:
a) Within the next 50 hours time-in-service after the effective date of this AD or prior to the accumulation of 1050 hours time-in-service on the heat exchanger/tailpipe assemblies, whichever occurs later and thereafter at intervals not exceeding 100 hours time-in- service:
1) Remove the right and left engine cowling.
2) Remove the coupling at the inlet end of the tailpipe and disconnect the supports at the opposite ends and remove the tailpipeassembly.
3) Drill a 0.50 inch diameter hole in the center tip of the cone shaped deflector. To simplify this procedure, fabricate a drill guide of phenolic or wood about 2.z0 inches in diameter. A suitable size pilot hole can be drilled in the center of the guide and subsequently in the cone shaped deflector. Enlarge the holes until the final size of 0.50 inch diameter has been achieved in the cone shaped deflector.
4) Boroscope each heat exchanger through the 0.50 inch diameter hole. If there are cracks or buckles in the baffle tube assembly, prior to further flight replace the heat exchanger/tailpipe assembly.
b) Airplane time-in-service shall be used for heat exchanger/tail pipe time-in-service unless the airplane maintenance records establish a different time-in-service for this component. When the heat exchanger/tailpipe assembly is replaced with a new part, the replacement assembly may accumulate 1,000 hours time-in-service before complying with the initialand 100 hour repetitive inspections required by this AD.
c) The time intervals between the repetitive inspections required by this AD may be adjusted up to 10 hours time-in-service to allow accomplishing these inspections concurrent with other scheduled maintenance of the airplane.
d) Airplanes may be flown in accordance with FAR 21.197, to a location where this AD may be accomplished.
e) An equivalent method of compliance with this AD may be used, if approved, by the Manager, Atlanta Aircraft Certification Office, FAA, 1075 Inner Loop Road, College Park, Georgia 30337.
Piper Aircraft Corporation Service Bulletin 762 dated May 26, 1983, pertains to the subject matter of this AD.
This amendment becomes effective on July 20, 1983.