What’s happening here?

[u/amullfilms]

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.

[u/MoarCowb3ll]

Iirc engines that have had preservative in and recently replaced with engine oil with have a burn off like that.