HELO, Hi exit, Low opening.  Used to describe airborne parachute maneuvers.

HELI---shorthand for HELICOPTER.

In Alaska in the sixties, I watched a high wind abort which dropped a 155mm
Howitzer ~1000 feet into muskeg.

This was a Sikorsky "Sky Hook" Helicopter caught in an oscillation from wind
gusting.

pensioner (whose E-Ticket ride was front seat in the AH-1 "cobra")