Woow... thanks for all the valuable comments.

@Dave McQueeney and @Alkaline: I think that current setup would be usable for canopy. The pressure failsafe can be disabled, no telemetry need, so you would have 5 programmable outputs, and 5 sequence steps. You can unlock, open the canopy, lock again... plus a extra 2 outputs and 2 steps to do other things like to move the arm of the pilot, etc.

@George: It would be possible to define a "power up" position, but so that this power-up position be compatible in all possibilities, the only safe position is with all doors open. You would not define a door closed at power-up when this door can interfere with the gear.

@Thud_Driver: Very nice and well thought your device. I have taken in to consideration to have the unit to remember what was the last position of the gear, but on plane that the mains are on the wings, often the position is changed manually by operator during assembly / disassembly, so it is not warranted that what is remembered is what is currently at power up, so I prefer a solution that is not dependent of what was done last flying session.

About the "do nothing" option. Could be the best one, but still are possible issues. First one is the definition of "do nothing". For servo actuated doors and Xicoy valves, OK, the sequencer does not output any signal so servos keep "soft" and valves keep both sides closed. Nothing moves. But for mechanical valves and some electronic valves that are open in either position even without valid signal, this could cause a odd power-up. Also there are planes that need air pressure to lock the gears.

After your comments, it seems to me that the best setup would be to add a programmable "power up" option:

Option 1: If command is "gear-up" do nothing. Once command is selected to gear down or if the power-up is already executed with correct "gear down" selection, then open all the doors, pressurize the gears and then close the doors that should be closed with "gear down". This mean that each time the power is switched on and "gear down" is selected, the doors that are closed will cycle open and close

Option2: Do nothing until the gear switch is cycled from "Gear Down" to "Gear-Up" and back to "Gear Down". Then perform the "option 1", pressurizing the retracts, open all doors, close the ones that should be closed.

Option3: Immediately execute the retract sequence as defined by the switch.

Option4: Open to suggestions...!

Gaspar