Bowersbum

thanks for the thoughts. one of our twins is getting one new starter. i'll try shutting down the old one and starting on the good and see what happens.

rotorhead1026

Tell us the result, willya? That's really interesting. If just some of the avionics turn off, it may be load / voltage related. If all of them go, it may be just one relay that's actually either designed to do this or is somehow malfunctioning. I'd almost say it's the avionics master relay itself, but those are supposed to be fail-safe (fail to "on"). I always just turned the avionics master off, but you may be in an area that's somewhat "transponder critical". A previous poster says there was no loss of avionics for him, so we have a mystery.

IceFlash

The avionics should not shut down on you as far as I know. I fly both the newer and older models, and have never had that happen to me on either one.

dimondan

I agree with IceFlash. Things really shouldn't shut down. Try turning one alternator off on the ground with lights and everything on while being on the gorund and see what happens. It might be that the starter is too much of a load on the system which isn't normal.

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multipilot

I've never had this happen either. I'd be very interested in knowing what you find out though. Perhaps load shed a little before you restart? Turn off your number 2 comm/nav and anything else non essential and see if it still does it. I know that the book recommends that you load shed anyway when on one alternator. I don't remember what the amperage is off the top of my head though. I want to say it says to keep the amperage below 60, but I very well could be wrong. But that's in a relatively newer Seminole with 70 amp alternators. Either way I think we can all agree that this isn't normal.

MobiusOne

The seminole I trained in would shake like a ***** in church on engine restart, but I never had an issue with the avionics turning off.

pilotinsky

The PA44 I flying only show left side alternator is charging when both are running; but if turn off one side, the other would come up alive.

Is this normal in the newer model, too?

ChillBillPilot

pilotinsky, Are you talking about this happening in flight? If so it is because there is not enough electrical load for the alternators to share, This happened alot to me on long cross counrty flights, I would get one alternator that would pick up the entire load and when I would shut that alternator down the other alternator would take up the load. Try turning on your nav, landing lights and and any other light that would place additional load on the alternators to see if they both would then start sharing the load.

As far as engine restarts in flight I always leave the avionics master on in flight and during restart it would not shut down. However you may be leaving the starter on for too long which would cause a large drain on your remaining alternator. I would try engaging the starter for up to 5 seconds, if the engine does not start give the alternator a chance to stabilize around 20amps and then try again. This will help to curtail the load being placed on the alternator.

pilotinsky

Yes, in flight.
That's what I thought so and sometimes it helps improve the radio transmission when I turn off that one side of alternator that is not sharing.
Possible electrical interference to the radio.

TheFly

Who here can identify all 3 holes on the Pitot-Static Mast on the the Seminole?