As an engineer I can tell you that any system, no matter how well thought through, designed and developed is simply a series of compromises. To achieve certain goals others must be sacrificed, you cannot have it all.
The piggyback container system we jump today along with the three ring release mechanism and ripcord method of deploying the reserve is a pretty solid system. Speak to the old vintage jumpers about what they used ‘back in the day’ and you will think them quite mad. It’s a solid reliable system but it remains a series of compromises between size, comfort, practicality, cost and so on. Any series of compromises will have a weak spot, a crack in the system so to speak. The gear that we jump has one as well, it’s a biggie too.
If your main parachute pilot chute is not functional or if it’s collapsible and has not been cocked you are playing in the cracks. You may think that if the pilot chute does not do its job you can simply do your reserve drills, get the spare out and all will be ok….well that’s not strictly true.
Your container when packed with both parachutes is pretty tight. The pin holding your main pack try closed is held firmly by the tension on the closure loop. This tension is imparted to the closure loop by the tightness of the container. Tight container..tight pin. Brilliant in its simplicity, potentially lethal if things do not go according to plan and fall outside the design parameters of the gear.
Imagine this scenario. At 3000ft you deploy your pilot chute, it has not been cocked and is non functional. It flies into the wind like a little handkerchief generating too little pull to overcome the tension on the pin from the closure loop. You now have a total malfunction or pilot chute in tow. Things are moving fast as well at this point. You do your reserve drills and the reserve flies out of the reserve pack tray above the main pack tray and starts to open. At the exact same time, because the container has been half emptied all the tightness relaxes. This relieves the tension on the main parachute closure loop and all of a sudden that pilot chute handkerchief pulling weakly as it is, is still powerful enough to pull your main out of the container. Before you can blink the main has wrapped itself into the reserve. You now have what is known as a ‘Main Reserve Entanglement’ and there is precious little you can do about it. Your karma better be in the green and your bucket of luck overflowing if you are to walk away from this one. It’s a scary proposition and it happens, it happens way too often.
The fix is simple and you do it on the ground. Make sure your pilot chute is in good condition ask a rigger or instructor to show you what to look for. If it is collapsible ensure that it is cocked. Most gear has a little tell tail marking to aid you in this. CHECK it and check your buddies. If in ANY doubt whip the pilot chute out, check and repack. It takes less than a minute. A few seconds to save a life. That little chute is the most important one on your gear because if that doesn’t work properly, nothing works properly.
Safe jumps people, and DFU.