Check essential!
Slackers.
Back in my plumber days we had an afternoon takeoff out of Billings in the summertime. Our stop margin was something generous like 7 or so.
As he pushed up the power the captain looked at the FO and I and said "Gentlemen, the only way we are getting airborne today is due to the curvature of the Earth. Set max power."
Bring on those UAL 757s I say.