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Which relays?
Jim
BTW, I did not use the magnetic reed
switches but put in position switches. I can’t see there’s any
problem electrically but the change did limit the variability of position of
the switches. I guess that’s the strength of having the reed jobbies. I
have Bosch relays for this job.
From: Lancair Mailing
List [mailto:lml@lancaironline.net] On Behalf
Of Tom McNerney
Sent: Wednesday, November 10, 2010
6:50 AM
To: lml@lancaironline.net
Subject: [LML] 360 flap failure
(Relay Failure?)
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)
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