Summary
The FAA proposes to supersede Airworthiness Directive (AD) 74-06-01, which applies to certain The New Piper Aircraft, Inc. (Piper) Models PA-23-235, PA-23-250, and PA-E23-250 airplanes equipped with Garrett Aviation Services (Garrett) (formerly AiResearch) turbosuperchargers installed under supplemental type certificate (STC) SA852WE, SA909WE, or SA978WE; or installed under Piper Aircraft Drawing Number 32016. AD 74-06-01 currently requires you to replace turbosupercharger oil tanks, install fire shrouds, seal all openings in the fire shrouds, and add drainage provisions in the oil tank fairings for airplane serial numbers 27-1 through 27-2504; and add drainage provisions in the air scoops on serial numbers 27-2505 and higher. This proposed AD is the result of a report of a fatal accident related to the breakdown of the turbocharger oil reservoir following a fire in the engine nacelle. Consequently, this proposed AD would require you to replace the oil reservoir and related hoses with a fireproof oil tank and fire-shielded hoses. We are issuing this proposed AD to prevent turbosupercharger oil reservoirs with inadequate fire resistance from failing when exposed to flame or exhaust gases. This failure could lead to an in-flight fire within the nacelle area penetrating the firewall and subsequent failure of the wing spar.