Quick question, not sure how many light airplane guys we have out there, but I figured this is driving me up a damn wall and here might be a good place to get an answer.
What turns off the landing gear pump in a Piper Seneca II (1978 PA34-200T) on retraction? I'm close to 100% sure that 3 closed down-lock switches turn off the pump when the selector handle is in the 'DOWN' position, but for the life of me I cannot seem to track down what turns off the pump in the 'UP' position.
The POH says in flowy imprecise language, that 'limit switches' turn the pump off once the gear is fully extended or retracted. This would lead me to believe that 3 closed up-limit switches turn the pump off.
HOWEVER, there's a pressure switch shown on the landing gear schematic and on the landing gear electrical diagram. It isn't mentioned anywhere in the text of the system description, but I seriously doubt that Piper installed a completely useless pressure switch on the gear system. Does this pressure switch turn off the gear pump when the handle is in the up position, a la later Piper products such as the Arrow and Seminole, or is the pressure switch some sort of overpressure cutout... I'm moderately confused.
Anybody got ideas?