I believe the analogy describing the impact by referring to falling or jumping from a particular height doesn’t account for the attitude of a BRS-equipped aircraft on impact with the ground following chute deployment. Since the aircraft descends in a nose-low attitude, the nose hits first (assuming level ground) absorbing a great deal of the impact energy -- the rest of the airframe would rotate downwards behind the nose until coming to rest (upright hopefully). Assuming the main gear hits after the nose, this would dissipate even more energy as it (the landing gear) is designed to absorb landing energies.

In short, landing under a BRS would be more like two smaller impacts instead of a single large one.

During jump training in the USAF we learned to do the same thing with our bodies; the Air Force calls it a Parachute Landing Fall – I don’t know what the other services call it. Essentially you land into the wind – feet first – then roll forward while rotating your body so as to dissipate the impact energy. Instead of keeping your feet and legs rigid so as to absorb the full impact – as the Cirrus would if it pancaked flat onto the ground – you roll sideways allowing your knees, hips and shoulders to take their share of the beating. If done properly, one can easily jump from 8 feet without (permanent) injury.

Mark

From: rtitsworth [mailto:rtitsworth@mindspring.com]
Sent: Wednesday, August 15, 2007 5:47 PM
To: lml@lancaironline.net
Subject: RE: [LML] Apologies to the farmer's daughter