h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

In Australia, prior to 1990, there were a number of unfortunate deaths from malfunctioning parachutes. This brought about the mandatory fitment of an American back-up system, which constitutes an altimeter triggering a small explosive charge if the rate of descent is that of a skydiver in freefall, and the skydiver has descended to 700 feet (210 meters) above ground level. The discharge deploys the parachute rapidly, preventing the disastrous sudden stop. I have been told that a skydiver still in freefall at 700 feet from ground is three seconds from eternity. Skydivers contacting the manufacturers for replacement explosive charges are referred to as "dead men walking". Since the introduction of these back-up devices to Australia, up to the time of writing there have been no subsequent deaths as a result of 'chute malfunction.

Well there was at least two who were sitting in a Porter with doors open and CYPRES engaged. Pulled the guy out of the seat and the plane in the ground. oops!
(the also say there are as many accidents with ejection seats as pilots saved)