Summary
We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:
Shortly after an engine change, the aluminium fitting attached to the engine gearbox holding lines and fittings of the propeller control system was found to be cracked. This led to a pressure loss in the propeller control system following a control system malfunction and led to an in-flight engine shutdown.
The broken fitting is part of the engine installation and was initially a steel part. It was later modified by the engine manufacturer to an aluminium design.
Investigation determined that the area is critical for cracks due to combination of mass, material and installation torque values.
Diamond Aircraft Industries incorporated with Design Change M[Auml]M 42-184 an additional bracket into production airplanes to improve the installations and prevent vibration cracks.
The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.