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!
![[Credit: Lisa Turner]](https://kitplanes.com/wp-content/uploads/2026/02/Fuel-Selector.jpg?w=218&h=150&crop=1 "Fuel Follies")
In Case You Missed It
Ask the DAR
DAR Mel Asberry clears up airspace restrictions for homebuilts during flight testing and discusses how the original builder of a homebuilt design remains the builder unless the airworthiness certificate is surrendered, which has implications for reselling an aircraft.
Build It Better: Building a Team
Sometimes working alone in your hangar is exactly what you want. But other times a helping hand is called for, and then it helps to know you’re part of a worldwide homebuilding community.
last time I looked, the vacuum pump drive spool had a 500hr OR 10 year service life whichever comes first.
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.
Vic
Comments are closed.