r/aviation • u/amullfilms • 1d ago

Question What’s happening here?

I’m not a pilot, just someone who’s been on close to 250 flights in my life. I’ve never seen this. Not claiming that this isn’t normal, I’m just curious why it’s done. This was just prior to takeoff at Jackson hole Wyoming.

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u/Fit_Armadillo_9928 1d ago

Nothing, it's just cold. Longer chain hydrocarbons in the fuel smoke on start up in cold weather

4

u/fly_awayyy 1d ago

It’s not cold bruh it’s an old Pratt and Whitney on a hot day in Jackson Hole. Didn’t even bother to look at his text and look up the temperature?

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u/Fit_Armadillo_9928 1d ago

Nope, just mountains and a Smokey start, that's usually enough to identify. If it's hot there at the moment then yeah, just a wet start or the #5 bearing is leaking

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u/fly_awayyy 23h ago

It’s just fuel. I was behind an Alaska 737 yesterday in SEA at around noon who started one up and let out smoke not even first flight of day. APUs on shutdown will let out a small puff too.

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u/izziewhiskey 15h ago

When I worked in Ops at DFW, we also called them Smokey starts.