Originally Posted by
TheStranger
Couple questions about the Seminole's landing gear that I have not been able to find answers to in the POH or through internet research.
What are the purposes of the pressure switch vs the electric uplimit/downlimit switches? How do they differ?
My understanding:
Pressure Switch - to turn pump off during gear retraction, once PSI reaches certain point. Also, turns pump on when retracted but pressure is lost.
Uplimit Switch (on each gear) - turns off red gear unsafe light when all 3 are closed.
Downlimit Switch (on each gear) - illuminates 3 green lights when extended. Turns pump off when all 3 are fully extended.
Is my understanding correct so far? Does the uplimit switch have any affect on the pump?
I find it very difficult to comprehend the electrical schematic in the POH, but I'm trying.
Does anyone have any other good resources for information about the landing gear system (diagrams, etc.)?
Thanks.
what do you mean by "pressure switch", by any chance is that the "squat switch"? (only on the left main I believe) that when on the ground, is not pressed. But upon lift off the gear extends a bit due to gravity and the weight of the aircraft being lifted off the wheels. This switch when working properly completes the circuit for the gear retraction. It serves to protect the pilot or any occupants from accidentally raising the gear while on the ground.
there is a switch on all gears for the lights (uplimit? individually activates the green lights just as or slightly after down locks are enganged) and then one more switch in the nose gear as that is the switch the turns off the pump. (nose gear is slowest to deploy down since it goes into the wind)
I dont remember for certain, but the red light is only just for when the gear is in transition or as a gear warning since your speed is too slow and or the switch in the throttle quadrant (roughly 15" mp or less on either throttle, you can hear the click sometimes) has been pressed. This may be linked to the 3 green circuitry, but im not sure. As for what turns the pump off, its either the uplimit switches or another switch up in the nose. Im not entirely sure, but ill look into it. I have a seminole POH somewhere.
Also, instead of looking at the schematic, have you read the systems description? Much easier to follow along.