The whole issue in my mind is
What is the minimum altitude / max VVI / worst attitude to expect a good deployment prior to ground impact?
E.g. if somebody stalls at 50 feet, they’ll be on the ground before they could even think to reach for the handle. Conversely at 5,000 feet they’ve got plenty of time to debate, dither, pull the handle and have a nice long ride even if the chute takes an unusually long time/distance to fully blossom.
As a representative example of a parachute-equipped lightplane, the Cirrus SR20 Pilot Operating Handbook is available from Cirrus at
The deployment procedure is on pdf page 65 and the system and decision-making discussion is on pdf pages 373-378. As an aside, I’m very impressed with this POH compared to the rather amateur and cursory 1960s/70s Cessna & Piper efforts I’m familiar with.
In a nutshell, they suggest deploying above 2000’ AGL if possible. And that from level flight 400’ AGL is barely enough. But even when lower down, deploying the chute will probably reduce the severity of the crash.
To be sure, even a partial chute is better than nothing. But whether it’s enough better to make the impact survivable is a separate question. With ejection seats we certainly have plenty of historical experience of people that got half a swing in a partial chute and hit the ground hard enough to shatter their spine, but not their head. They never walked again, but they did live. Others fared better or worse based on the luck of the draw and timing.
Ultimately Cirrus’ advice amounts to: If you’re not certain you can make a controlled forced landing on favorable terrain, pull the handle and hope for the best. Which mirrors the guidance in the F-16 POH-equivalent: If you’re not certain you can make a controlled forced landing on a long-enough runway or taxiway, pull the handle and hope for the best.