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Three years back at the regional hangar, a new guy argued we should skip the full engine run after a magneto change
He said the ground test was enough and it would save an hour of fuel and time. I saw a Cessna 172 come back with a rough idle the next day because of a bad mag lead we missed without that run. Now some guys still say it's overkill for simple swaps, but I won't sign off without hearing it myself. Where do you all stand on cutting that step?
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thompson.finley5mo ago
Oh man, that's a scary story. I read a service bulletin years ago that basically said a ground check won't always catch a high-altitude mag failure. You can get a good spark at sea level that completely falls apart once you're up in the thinner air. That final run-up is the only real proof it works under actual flight conditions.
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oscar3903mo ago
Honestly, I gotta push back on that "only real proof" line. Ngl, I've had a mag act totally different at altitude than on the ground, but a good ground check still catches most problems if you're doing it right. @haydengreen's point about swaps being straightforward is fair, but saying the final run-up is the only test feels like overkill when a thorough ground run can show weak spark too.
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haydengreen5mo ago
Doubt that's a real problem these days. Most mag swaps are pretty straightforward, seems like extra work for almost no gain.
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