Hi everybody i'll just put up a quick note about an incident which could have had major consequences but which miraculously came out ok. I'll make it as simple as i can but this post couldn't acount for the sheer fear that this incident brought to me. This note is written only on an informative purpose as I have had misinterpreted/deformed feedback from the incident, even from close friends. NB: for french speakers I posted the same report on www.wuza.net "la routine tue" Second load of the day, plane goes up i'm ready to go on a three way, on the way up my sound altimeter beeps at a wrong and low altitude, I still have my hand altimeter it should be ok. As I exit the plane I feel my harness is loose, I look down and there's my chest strap flapping loose! I spend the jump battling to put it back into place and when I finally manage to do so I put my left hand on the reserve handle. At that precise moment my audio beeps for the first time, in the moment I forgot it was bust and therefore reach for my main canopy. Canopy opens nicely I then look at the ground and back to the dropzone, I pull the toggles to inflate the end cells and make a turn to get back to the DZ as I release the toggle my canopy carries on its course and starts flying vertical in front of me. What I din't realise was that I was far too low and that my AAD had fired, the reserve was out and inflated on the turning motion leading to a downplane configuration. I put my hand on my cutaway handle, look at the ground and think to myself: this is too low you'll never get the reserve out (I didn't realise it was actually out until I found myself wrapped in it on the ground!) so my hands reach for the main rear risers and pull as hard as I can foolishly thinking that it would get back to normal. I impacted on soft and muddy grass a few meters away from the tarmac. Luckily it turned out that no bones were broken and I ended up with severe pain in my back. Lessons that I learned that day: A) even though one of the jumpers I was with confirmed that he saw my chest strap closed before boarding, the fact that it was loose on exit only means that I dind't do it up properly. Therefore I came to the conclusion that you are the only one in charge of your own safety. NB: If your chest strap is loose keep in mind that there is a procedure for it which consists of holding the right strap of your harness with your left hand, release the HD, bring your right arm to your left strap and hold on tightly. This is of course for you to confirm with your own instructors! B) Don't rely solely on your audio altimeter, always double check with you hand altimeter C) Always be careful of your canopy openings and the way you behave right after deployment, make sure that there is only one canopy out (especially after a low stunt like this one). All of these are actually textbook lessons and the reason I made those was my excess self-confidence due to a long serie of uneventful jumps prior to this one. I can only conclude that this incident was the result of gradual neglecting of safety by my own person and that there is nobody else to blame but I. Fly safe and blue skies J.