Hi All,

Jeff is trying to make some decisions relating to instrument/systems redundancy and backups and asked if I might start a thread here for thoughts from all of you.

Having put off transfer of Jeff's #2 vac pump to his new engine, it was a surprise when we opened the aft pad and found no receiving gears in the case... shame on us, and Lycoming since they have always known what installations we are replacing and never reminded us we would need to specially request these gears. Shame on me for forgetting for an instant that anything not checked is likely missing, wrong, or broken.

Before just solving this issue the hard way, Jeff and I have been talking through his redundancies and backups in general. While willing, of course, to install the gears and transfer the pump, I have recommended against for two reasons:

1. Burden on the engine:

Driving four accessories is a bit over the top. Jeff reported engine stalls when he tried to use a/c on the ground (thus loading his 2nd alternator) and I've personally heard other B models balking at low RPM. More accessories place a higher average burden on the engine and add powerplant failure modes. I have recommended leaving off the 2nd vac pump, in favor of using a Precise Flight for that redundancy.

2. Everything still reliant on the engine:

Jeff has two horizons, but both dependent on the engine. He also has two alternators but again both dependent on the engine. He has nothing to help him let down after an engine failure except anything portable he might have strapped to the yoke. I have suggested we change up his electric horizon to a battery-backed LifeSaver to leave him something working in the panel in addition to pitot static instruments.

Jeff is more inclined to have me just install the gears and transfer over the 2nd vac pump.

OK, your nickel everyone...

Jim