Summary
We propose to adopt a new airworthiness directive (AD) for all Piper Aircraft, Inc. (Piper) Model PA-28-161 airplanes equipped with Thielert Aircraft Engine GmbH (TAE) Engine Model TAE-125-01 installed per Supplemental Type Certificate (STC) No. SA03303AT. This proposed AD would require installing a full authority digital engine control (FADEC) backup battery, replacing the supplement pilot's operating handbook and FAA approved airplane flight manual, and revising the limitations section of the supplement airplane maintenance manual. This proposed AD results from an incident where an airplane experienced an in-flight engine shutdown caused by a momentary loss of electrical power to the FADEC. We are proposing this AD to prevent interruption of electrical power to the FADEC, which could result in an uncommanded engine shutdown. This failure could lead to a loss of engine power.