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On my second solo flight I came back to do a few landings, and after the first landing I applied full power for takeoff to which the engine responded by just shutting off on me. Not sure if my mixture was too lean, if I applied power too quickly (which I read can temporarily lean mixture too much to keep the engine running), or something else. My CFI wasn't sure what caused this either.

After an embarrassing talk with ATC I was able to get it started up again just fine, and the plane has ran well ever since, so I'm 99% sure I caused the incident. Just not sure exactly what.

I fly a 1976 Cessna 150M. Airport elevation is 5500 above sea level (hence why I leaned my mixture in the first place, as it's advised in the POH). Weather that day was around 0C but very arid.

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    $\begingroup$ Unless you were operating at a high altitude airport why was your mixture anything but full rich on approach/go-around? $\endgroup$
    – Dave
    Dec 11, 2020 at 19:39
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    $\begingroup$ Hmm... as Dave pointed out, mixture full rich should be a memory item... $\endgroup$
    – Jpe61
    Dec 11, 2020 at 20:01
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    $\begingroup$ seems to me the only mistake you made was "I was able to get it started up again just fine, and the plane has ran well ever since" - I wouldn't touch an airplane that cut out on me for no reason. $\endgroup$
    – java-addict301
    Dec 12, 2020 at 5:44
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    $\begingroup$ @java-addict301that was a later update and was not included in the original question (hence my note) $\endgroup$
    – Dave
    Dec 12, 2020 at 5:59
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    $\begingroup$ @java-addict301 If the engine had backfired, started smoking, or otherwise behaved violently I would not have done that. In this instance it literally just smoothly shut off, as if I had cut off the mixture. With my (limited) knowledge on engines, I didn't see anything unsafe about simply starting up again. $\endgroup$
    – Allihusk
    Dec 13, 2020 at 1:22

1 Answer 1

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The most likely cause of your engine cutout is what's known as a rich cut caused by coarse application of full throttle. Most carburetors have an accelerator pump which jets extra fuel when the throttle is pushed in quickly, this is to make sure the engine has enough fuel and prevent what's known as a lean cut. However, at high density altitude your mixture needs to be leaner than at sea level, so it can in some circumstances do the opposite and give your engine too much fuel to burn.

It's also possible your mixture was too lean, so advancing the throttle caused it to die on you. There's no way to know for certain.

In the future advance the throttle smoothly, it doesn't have to be super slow, just don't jam it in. 2-3 seconds from idle to full is about right (same goes the other way too). If it starts going gluk gluk gluk on you enrich the mixture a couple of turns and see if that resolves it. Don't forget on a touch and go you have the option to abort, don't be afraid to use it if there's issues. Remember that takeoffs are optional, landings are mandatory.

And remember that carb heat! Icing can happen in any conditions.

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    $\begingroup$ Yes, I had this happen (once - never say I don't learn from experience!). Not on takeoff, but wanting to make a climb. Luckly the prop was windmilling, so the engine caught after a couple of seconds. $\endgroup$
    – jamesqf
    Dec 12, 2020 at 3:19
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    $\begingroup$ That must have been an interesting few seconds @jamesqf! $\endgroup$
    – GdD
    Dec 12, 2020 at 8:19
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    $\begingroup$ I had the opposite happen back in the mid 70s flying a flying club Bowers Flybaby homebuilt that had a Cont C90 with no accelerator pump and no starter. It just died when I added throttle a bit too abruptly on final and I rolled to a silent stop halfway down the runway. I arrived back at the ramp a little tired, to the surprised look of some of the locals, walking with the tail on my shoulder, pulling the thing along backwards like Jesus dragging the cross (a cross with handy rubber tires; the Flybaby was a small single seater and was light enough to do that). $\endgroup$
    – John K
    Dec 12, 2020 at 13:24

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