Dual alternator failure and complete electrical failure
 

About nine months ago I had both alternators fail during flight. I had 40 minutes to go to get to my maintenance base. I used minimal electricity to last me most of the flight ( last 10 minutes or so I had no electric power) and the first item I did after the failures was lowered the landing gear. So I flew at around 130 mph to my mechanic. My question is: do the gear doors open when there is no electrical power? I have a 337B. I’ve read over the service manual, the landing gear diagrams and the POH and I’m still not sure about the answer. Thanks

I think they will open but not close. I’m not a pilot but maintained 6 for @ 28 years. You don’t need power to open them but you need power to close them.

That would make sense since on the ground you can pump the gear doors open with the hydraulic pump handle and when you close the doors on the ground you must turn on the master switch then pump the handle to close the doors.

Found it
 

Thanks 😊 after reading further into the service manual I found the answer to this question. The door solenoid valve shifts valve to door-close position when energized. Spring-loaded to door-open position. Thus with an electrical failure, the solenoid valve will remain in the door-open position and doors cannot be closed.