COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Piper PA-34 (Seneca) Series Aeroplanes AD/PA-34/38 Exhaust System Heat Exchanger - Inspection 9/83 Applicability: All model PA-34-200 with S/Nos. 34-7350342 to 34-7450220. All model PA-34-200 with S/Nos. 34-7250001 to 34-7350341 which have installed exhaust system replacement Kit 760 764V in accordance with Piper SL 673. Document: Piper SB No. 762. Note: FAA AD 83-14-05 refers. Compliance: 1. On or before 1000 hours total time in service of exhaust tailpipes and repeated thereafter at intervals of 100 hours time in service. 2. Within 100 hours time in service of exhaust tailpipes after 30th September 1983 where in-service hours cannot be established. 3. The inspection criteria detailed in item 1 of the compliance shall also apply to replacement tailpipes. Background: The manufacturer has received reports of the heat exchanger inlet port, cone shaped deflector, breaking away from the baffle tube and lodging against the exhaust port of the tailpipe. If this occurs, significant power loss will result, as well as the possibility of engine stoppage.