jjcote wrote:
The doubling of strength by doubling over the strap strikes me as irrelevant. If you're pulling enough load to break a hang strap, you're already in way serious trouble. And there's no point in making the extension stronger than the strap it's hooked into. But I agree that a backup from the hang strap to the 'biner is pointless. A backup to the keel would provide protection for something like the bolt holding the hang strap to the kingpost backing out. (Or failure to properly hook into the extension.)
To JJ,
Respectfully- you recognize the potential for wear of the hang loop, but then say doubling the strength is irrelevant? If a hang loop did get worn to say 50% of it's original strength... would you rather it be single-ply strong, or double-ply strong?
To Everyone,
I hope you all have actually looked at the "main sewn to the backup" hang loop system? They are two separate loops completely- one bolts to the kingpost-hang, while the other goes over the keel and is connected with a maillon. Below the spreader bar the two loops are sewn together for simplicity, aerodynamics, and safety- it's impossible to hook in to the "primary" but forget the "secondary". It's very simple, yet very clever if you think about it. Also, the backup is just barely longer than the main- on most other setups, if you end up hanging on the backup you'll be a good 3 (or more) inches lower... good luck flying and landing like that. Although it still beats FALLING OUT!
Looping a backup through the same double-hang-loop IS
NOT POINTLESS, because as I explained that double loop *is* both connected to the kingpost AND around the keel... so if you connect an extension to the double hang loop, it's not a bad idea to also connect a backup to the double hang loop too. In this case it would have prevented the pilot from exiting the aircraft unexpectedly!
Speaking of the pilot exiting unexpectedly- two questions came up (and maybe those that know the pilot could answer or ask him?)....
1. After returning to Earth under canopy, was the extension hang loop connected to the pilot's carabiner? If it WAS the method where you hook in on one side of the hang loop, put the extension loop through the hang loop, and hook in to it again... and the pilot only hooked in to one half... and it slipped through the tape finally... he would have had the single loop hooked through his biner a single time still, right? Seems it would be pretty easy to see if he didn't hook in to it twice?
2. What kind of harness, and how was the reserve attached (to the biner, or internally)? In his report he mentioned his descent under canopy was in the upright position and leaning slightly forward... but in most conventional harnesses the reserve runs along the harness main and connects at the biner... and so in a deployment he'd be suspended just as he would hanging in a hang glider- prone. Maybe if he got his legs out, sunk down into the leg loops, and arched his back he could have gotten upright... but it's surprisingly hard- even in the best get-upright harnesses- when you've got no glider to hold on to. That description just struck me as slightly odd...
Anyway, obviously super happy to hear the pilot is OK! And really appreciate his willingness to share his story, rather than keep it mum. Since it happened in Meheeco, if this pilot didn't tell about it, most of us wouldn't never heard about it.
I'm not sure there are really any new lessons here specifically- but the bigger picture lesson is ever-valuable... aviation is an unforgiving mistress, and we need to apply the utmost diligence to every detail. ESPECIALLY hooking in! This shows mistakes happen... which is why we check and triple check things BEFORE launching. It's understandable how he might have hooked in incorrectly, as he's just a guy like the rest of us. But how he got in the air like that (if that IS what happened)... is actually a SERIES of forgetting things, or a SERIES of failures... and that is something we can not allow of ourselves or our friends! Everyone's allowed to make mistake(s)... but we need to be so careful it's highly unlikely we link a bunch of compounding mistakes together... and that our friends are watching our back still... so THEY would need to ALSO make the same mistake(s)- like checking you are hooked in during the hang check. The chances of a diligent person failing to connect correctly, failing to double or triple check that connection, and their friend(s) also failing to spot it and/or forgetting to check up on their buddy before he launches... like make sure he does a hang check, and then the hang checker actually... well, checks...
So- lesson learned? Move slow and deliberate, doubt yourself and check everything repeatedly, and then have your friends check you too... chances of this kind of thing happening if all of that happens? Pretty unlikely IMHO...
Shut up and fly.