NTSB report N732SX

[WaiexN143NM]

Hi all,
Some good reading on released accident report from N732SX, crash Feb 17, 2014 in Florida. Posted on www.kathrynsreport.com dated 12 dec 2015.

WaiexN143NM
Michael Radtke

[Bryan Cotton]

Full NTSB narrative here:
http://www.ntsb.gov/_layouts/ntsb.aviat ... 123&akey=1

Some of my former co-workers knew the pilot. One of them lived at the same airpark. They told me about the bad plug repair. I didn't want to say anything until the NTSB report came out.

Seems like a Sonex should be able to maintain altitude with one bad cylinder. Florida is very flat and low altitude.

[vigilant104]

Seems like a Sonex should be able to maintain altitude with one bad cylinder.

Maybe it would have (others have), but it doesn't sound like the pilot tried that before executing the turn that led to the stall and "spiral".

A Sonex isn't a sailplane, but it glides safely if the critical AoA isn't exceeded. It remains controllable to low airspeeds, and is structurally tough enough to provide good protection if set down in good/marginal terrain in a normal attitude and near Vso.

But we don't, and we can't, know all the factors that influenced the pilot's decisionmaking in this case. He had a lot of experience, surely could have recited the correct procedures based on a given situation, had practiced loss of power scenarios scores of times in sophisticated simulators, and yet we have this result. "Knowing" and "doing" aren't the same thing, and I'd be the last to say that I would surely have come out any better than he did.

A possibly related comment: Aluminum heads are soft, and the spark plug hole threads are easily damaged even if a great care is taken to avoid cross-threading, overtorquing, etc. As mentioned in another thread, many folks with a lot of experience trust the new Timesert thread repair method more than the older Helicoil method.

[Onex107]

I have experianced a three cylinder take off. It acted llike a stuck valve. Just after leaving the ground it went to three cylinders. It runs rough like that but it still makes power. It will hold altitude and climb very slowly. You are working on the edge, between climbing and a stall, and this is flying straight out, runway heading. A turn is out of the question. After making it up to 1000 ft. above ground the cyliner came back on and I flew for an hour without a problem. That happened during the 40 hour fly off and never occured again.