Disintegrated Drive Coupling



Ever wonder why the standby alternator or vacuum pump isn’t working? There is a drive coupling that is designed to break if something becomes stuck. They are also supposed to be replaced every 500 hours or they can start looking like this!

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Vic is a commercial pilot, CFII with ASMEL/ASES ratings, an A&P/IA, DAR, and EAA technical advisor and flight counselor. Passionately involved in aviation for over 40 years, he has built 11 aircraft and logged over 10,000 hours in 72 different kinds of aircraft. Vic volunteers as a Young Eagle pilot and Angel Flight pilot. He chairs the EAA Homebuilt Council and is a member of EAA’s board of directors. He also has his own sport aviation business called Base Leg Aviation.


  1. Perhaps this is newer data than when you last looked, butTempest has a service letter, SL-001 which recommends replacement every 6 years.
    In our glass cockpits the standby alternaotr seems pretty important. That’s why we recommend 5 years.



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