Summary
We propose to revise an existing airworthiness directive (AD) that applies to TAE models TAE 125-01 and TAE 125-02-99 reciprocating engines installed on, but not limited to, Diamond Aircraft Industries Model DA 42 airplanes. The existing AD currently requires initial and repetitive replacements of proportional pressure reducing valves (PPRVs) (also known as propeller control valves). Since we issued that AD, TAE has increased the life of the PPRV, part number (P/N) 05-7212- E002801, on TAE 125-02-99 engines, from 300 hours to 600 hours. This proposed AD would relax the repetitive replacement interval from a 300- hour interval to a 600-hour interval for PPRVs, P/N 05-7212-E002801, on TAE 125-02-99 engines. We are proposing this AD to prevent engine in- flight shutdown, possibly resulting in reduced control of the aircraft.