Auburntsts
Well Known Member
I have recently developed erratic RPM indications on my legacy G3X. This developed on a long cross-country flight over Thanksgiving and was duplicated on a local flight this weekend. The sensor is mounted on my right mag (Slick 6350) and has 202 hrs on it. Here's the symptoms:
-- At full power RPM rapidly swings from the mid 2300's all the way to 3000 regardless of prop gov setting.
-- The prop gov (PCU5000) is functioning properly and the RPM isn't actually changing, just the indication.
-- After startup and all the way thru run-up, the RPM indications are normal, then on application of full power on takeoff the erratic behavior begins immediately as the RPMs come up to/near redline.
-- Indications return to normal at idle once on the ground, but will go wonky if power is reapplied.
-- The right mag itself seems to be functioning normally, although I have not attempted a high powered mag check.
-- Externally, nothing is loose or frayed.
This behavior happened once before on a very bumpy local flight back in April (about 50 hrs TT ago) but disappeared on all flights until now. I thought back then that the turbulence might have jarred something in the wiring from the sensor to the ADAHRS, but the indications didn't reappear until now. When it did I was in cruise and the air was smooth
(8000ft, ~21MP, 2350 RPM, highest CHT was ~368 (normal for me), and oil temp ~186).
I have a blast tube on that mag although the sensor doesn't really benefit directly due to the location of the sensor on the mag which places it under my backup alternator on the vacuum pad.
Does this sound like the sensor is dying or something else?
-- At full power RPM rapidly swings from the mid 2300's all the way to 3000 regardless of prop gov setting.
-- The prop gov (PCU5000) is functioning properly and the RPM isn't actually changing, just the indication.
-- After startup and all the way thru run-up, the RPM indications are normal, then on application of full power on takeoff the erratic behavior begins immediately as the RPMs come up to/near redline.
-- Indications return to normal at idle once on the ground, but will go wonky if power is reapplied.
-- The right mag itself seems to be functioning normally, although I have not attempted a high powered mag check.
-- Externally, nothing is loose or frayed.
This behavior happened once before on a very bumpy local flight back in April (about 50 hrs TT ago) but disappeared on all flights until now. I thought back then that the turbulence might have jarred something in the wiring from the sensor to the ADAHRS, but the indications didn't reappear until now. When it did I was in cruise and the air was smooth
(8000ft, ~21MP, 2350 RPM, highest CHT was ~368 (normal for me), and oil temp ~186).
I have a blast tube on that mag although the sensor doesn't really benefit directly due to the location of the sensor on the mag which places it under my backup alternator on the vacuum pad.
Does this sound like the sensor is dying or something else?
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