Fuel Selectors/Pumps
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In the piston the checklist puts the fuel selectors on crossfeed with pumps off for the entire flight until final. In the turbine the crossfeed is on during run-up then "on" only, not cross fed for actual flight, but wing pumps on the entire time. Yet, on final the checklist in the turbine says to put wing pumps on. They're already on, if following the checklist.
What should be the normal position in either of these types for on versus crossfeed and pumps on/off? I'm not seeing a clear answer in the manual about the proper positions.
Thx, Chris
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I just checked the checklists, and both call for fuel selectors on by the end of the runup checklists. Crossfeed is selected during runup to ensure that all fuel lines are working, but they should always be operated in the on position for normal flight.
As for fuel pumps, they should be operated as with most low-wing aircraft. They should absolutely be on for takeoff, and on for landing and approach operations. Essentially, anywhere you really don't want to have an engine failure due to loss of the engine-driven pump. There is nothing wrong with leaving these pumps on throughout the flight, but it's also not necessary. The Turbine Duke does have a special operating limitation that the aircraft cannot be operated without all four pumps in working condition, though.
One final note, because I've seen similar questions with my other aircraft. Just because a checklists calls for something twice, as you note with the fuel pumps before landing, does not imply accidental redundancy. That should be a cue to the operator that the manufacturer really wants to make sure that you've set that control correctly before the next phase of flight.