Precise Flight Speedbrakes Fail to Retract While in the Air

[Tom Nalevanko]

Flew a number of flights last week in Wickenburg/Buckeye AZ. Most flights at 5,000 ft but one up to 17,000 ft. Speed brakes used a number of times without issue. However, on last flight at 5,000 ft the speed brakes would not retract — tried switch on yoke and also switch on panel. Pulled breaker and speed brakes retracted. Breaker had cut off red wire tie around it, so previous owner was ready for this.

Back on the ground, the speed brakes deploy/retract normally using the switch. Curiously enough, pulling the breaker on the ground with the speed brakes deployed has no effect — they remain deployed?

Have reviewed all the posts and schematics available online. My suspicion is the relays and I see mention of a relay circuit board. Would appreciate any insight or suggestions for repair.

Thanks,
Tom

Lancair IV-P N124GH

[Admin]

Tom, confirm both speedbrakes do this, not just one? I had this issue with one and it turned out it was a broken spring inside the unit. They are fairly simple to work on.

If both speedbrakes stay up inflight until you pull the circuit breaker, I'd say it is the controller. Be advised that Precise requires a full rebuild if you send a controller to them. They won't just replace the broken part. Expect the until to set you back a few AMU.

-Ryan

[Tom Nalevanko]

Ryan,

IIt’s definitely both Speedbrakes. I will do more ground testing to see if I can hear a motor running, or something…

I removed the panel at the root of the wing — where the fuel probe enters the wing. I didn’t see anything except wire bundles so I suspect that I have the latter version of the brakes.

Re the suggestions, if just one brake remains deployed, it is likely a spring, if both the controller. I’m hoping for something needing lubrication… I know, dreamer…

Blue skies,

Tom

[Brad Simmons]

What vintage is your airplane? Do you have a picture of the speedbrakes when retracted?

[George Wehrung]

And if power is removed the springs are supposed to takeover and retract the springs.


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