Gear doors slow to close

[hew]

If you have problems with the gear doors as per my previous thread I have solved the problem. Step one, replace both up-lock switches. No more steps!

I replaced one switch which made to problem intermittent, once I had replaced both switches I have had no more problems. The red herring in this issue was that the system worked perfectly well during retract tests and the switches checked out when tested and operated manually. For some reason, vibration in the air was preventing them contacting reliably. Without a complete electrical circuit around all the up-lock switches the doors won't close. At $70 each it's a very cheap fix before you go looking for other problems.

[hharney]

Thanks for the response and glad you got the problem isolated to the switches.

[hew]

Between the door unlock actuator and the unlock hooks there is a bell-crank, one on each side. Hydraulic pressure unlocks the hooks by pulling the bell cranks inwards. A spring inside the actuator pushes the unlocks out to reset them.
The bolt through the fulcrum had been overtightened so sometimes, usually first retreats, the spring only slowly pushed the unlock hooks out. Retracting the gear before the hooks had time to fully move out prevented the unlock switches properly engaging the legs so the doors didn't close.