Summary
We propose to adopt a new airworthiness directive (AD) for certain SOCATA Model TBM 700 Airplanes. 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:
A TBM700 operator reported an occurrence where, as a result of handling the standby compass lighting bulb cover in flight, both essential bus bars (ESS BUS 1 and ESS BUS 2) failed, leading to loss of a number of instruments and navigation systems.
The technical investigations carried out by SOCATA have shown that the cause of this occurrence was that the electrical protection of some TBM 700 aeroplanes is insufficient to allow in-flight handling of the standby compass lighting cover when energized.
This condition, if not corrected, may compromise the ability of the pilot to safely operate the aeroplane under certain flight conditions due to the increase of workload.
The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.