So I'm on downwind, select a touch of flaps on my momentary flap down
switch, and I soon find the flaps are still extending. Pushing the flaps
up button does nothing. They continue past the limit switch until the
flap motor hits the mechanical limit and pops the breaker. From the
cockpit I could look directly down at the ground where the flaps normally
are. Not to mention the fact that it felt like a massive speed
brake. I was able to land with very little pitch up authority
left. This all happened in about, oh.. 25 seconds.
The real bitch of it was this. Get it back to the hanger, reset the
flap motor breaker, select flaps up and everything works. They are back
to obeying their limit switches like normal. I probably ran those things
up and down 50 times and couldn't get it to fail again. Checked all the
wiring, couldn't find a problem. Until... I caught
it. The down flap relay fused and got stuck on, thereby bypassing
the limit switches, and pretty much everything else, only being stopped by the
flap motor blowing the breaker. Once it cooled down the relay would
release and return to normal operation.
So, even if the relay is wired correctly, and works as designed
sometimes, doesn't mean it will on short final. Relays get old,
like everything else. If I were you, you might consider new relays. (if
your airplane has them I guess)
Tom