Summary
We propose to adopt a new airworthiness directive (AD) for all Technify Motors GmbH TAE 125-02 reciprocating engines with a dual mass flywheel installed. This proposed AD was prompted by reports of a gearbox drive shaft breaking during starting or restarting of the engine. This proposed AD would require installation of a start phase monitoring system and associated specified software. We are proposing this AD to prevent overload and failure of the gearbox drive shaft, which could lead to failure of the engine, in-flight shutdown, and loss of control of the airplane.