Lead Sled
Sitt'n on the throne...
- Joined
- Apr 1, 2004
- Posts
- 2,066
Sorry guys, I'm in the middle of a move and got things a bit twisted. What you said about the fuel pump is correct, however there are fuel pumps (transfer pumps) in various locations in the fuel systems of many aircraft - some are fuel lubricated and some aren't.
As a general statement, in most piston-powered light aircraft, you're not going to damage an engine-driven pump if you run it out of fuel. Electrical powered transfer pumps are a different animal - many of them are fuel lubricated and you can damage those if you allow them to keep running with out fuel.
The whole point of this thread isn't about fuel pumps - it's about the wisdom of making sure you can access the fuel in all of your tanks before takeoff and how to safely do it. Knowing how long it take to run a fuel line dry at idle power is about the only method you have to know how long an eninge will run if its fuel is interrupted. You only have to do it once per tank - not every flight. If the number happens to be 40 seconds and it's been 3 minutes since you switched tanks you're in fat city. If the number is 40 seconds and you just switched tanks 10 seconds ago and now you're applying takeoff power - well, you could have a real problem in about a half a minute.
The same advise goes for checking that you can actually draw fuel from the opposite tank via the crossfeed lines when you're flying your light-twin.
Checking the fuel continuity is a pretty big deal. I seem to remember that about 20-25 years ago there was a problem with the fuel selector valves that Piper had installed in several different single-engine models. It was part of the taxi checklist to switch tanks and verify fuel flow.
'Sled
As a general statement, in most piston-powered light aircraft, you're not going to damage an engine-driven pump if you run it out of fuel. Electrical powered transfer pumps are a different animal - many of them are fuel lubricated and you can damage those if you allow them to keep running with out fuel.
The whole point of this thread isn't about fuel pumps - it's about the wisdom of making sure you can access the fuel in all of your tanks before takeoff and how to safely do it. Knowing how long it take to run a fuel line dry at idle power is about the only method you have to know how long an eninge will run if its fuel is interrupted. You only have to do it once per tank - not every flight. If the number happens to be 40 seconds and it's been 3 minutes since you switched tanks you're in fat city. If the number is 40 seconds and you just switched tanks 10 seconds ago and now you're applying takeoff power - well, you could have a real problem in about a half a minute.
The same advise goes for checking that you can actually draw fuel from the opposite tank via the crossfeed lines when you're flying your light-twin.
Checking the fuel continuity is a pretty big deal. I seem to remember that about 20-25 years ago there was a problem with the fuel selector valves that Piper had installed in several different single-engine models. It was part of the taxi checklist to switch tanks and verify fuel flow.
'Sled
