Canuck
David Megginson
- Joined
- Mar 31, 2016
- Messages
- 7,087
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My plane just came out of annual. On climb-out during my post-maintenance test flight, I experienced a 400 RPM power loss over about 5-10 seconds just long enough after liftoff that I had no runway left to put it down.
Since I was low, I focussed on getting the plane into an aerodynamically stable state first (I was still climbing slightly at Vy), turned to a low 600 ft downwind to avoid the restricted airspace ahead, and started troubleshooting.
Switching tanks and turning on the boost pump didn't help (I suspected fuel contamination after the time in the shop), but as soon as I tried carb heat (another ~100+ RPM loss by that time), I knew I'd solved it--the engine ran violently rough for a bit, then the power came smoothly back up as if someone were moving a throttle forward.
I hadn't been watching for carb ice under a clear blue Arctic airmass with -15c OAT, but there it was, all the same.
Since I was low, I focussed on getting the plane into an aerodynamically stable state first (I was still climbing slightly at Vy), turned to a low 600 ft downwind to avoid the restricted airspace ahead, and started troubleshooting.
Switching tanks and turning on the boost pump didn't help (I suspected fuel contamination after the time in the shop), but as soon as I tried carb heat (another ~100+ RPM loss by that time), I knew I'd solved it--the engine ran violently rough for a bit, then the power came smoothly back up as if someone were moving a throttle forward.
I hadn't been watching for carb ice under a clear blue Arctic airmass with -15c OAT, but there it was, all the same.
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