Quality control...

[bwilling 0]

Background - I recently purchased a kill line collapsible pilot chute from Para-Gear, and I won't specify who the mfg was, but I guess it would be a 'brand name' in the skydiving community, just not someone who's equipment I've ever jumped.

Having recently read Bill Booth's post regarding proper design and construction of pilot chutes, I did a thorough inspection of my new P/C. And it failed! Fully cocked, the apex of the P/C was noticeably below the skirt! I had my rigger look at it, and he confirmed that it was indeed 'defective', and I returned it Para-Gear (easily I might add), and ordered one from Sunrise Rigging (who made the original, which is correct).

So I'm curious, as someone who's been around (conventional) manufacturing for the last 30 years, what kind of quality control systems are in place in the skydiving equipment industry? And how the hell do they even check most of that stuff they build??? We have all kinds of cool technological toys to inspect the parts we manufacture at work, how the hell do canopy mfgs inspect a finished canopy after it's all stitched together? Kite it, and go... well, that looks about right?

"If all you ever do is all you ever did, then all you'll ever get is all you ever got."

[mr2mk1g 10]

Just so I'm sure: which way up are you holding the PC when you say the apex is "below" the skirt? By the bridle or the hackey?

[IanHarrop 42]

click the link to Bill Booth's post. The information there is VERY detailed.

"Where troubles melt like lemon drops, away above the chimney tops, that's where you'll find me" Dorothy

[pilotdave 0]

It's been proven over and over and over again that even though one design of anything may be superior, many other designs will work just fine, if not quite as well. I'm not just talking about pilot chutes, but everything.

If you'd never read that post by Bill Booth, you woulda used that "defective" PC and probably wouldn't have noticed any difference. But that doesn't make it just as good.

The post you linked to is one of the big reasons I chose a Vector. Why buy from someone that read the best way to make it when you can buy from the guy that invented the best way to make it?

Dave

[CReWLL 0]

To generate the highest drag, the center-line (kill line) should be 10 % longer than the suspension lines of the canopy. The suspension lines being the tapes on the mesh. If they are 12", the center (kill) line should be 1.2" longer. If you have a 30" p/c the kill line should be 1.5" longer. Measure it with some load on the whole bridle (like 50-75 lbs) you will be surprised how much the nylon part of your bridle stretches (which will make your kill line effectivly shorter).
In regard to the support tapes being sewn on the bias of the mesh, this gives you a pilotchute with 8 suspension lines vs a pilotchute with 4 lines. The "block" direction of the mesh acts like 4 of the lines, and the tapes act as 4 lines. If the tapes are sewn along the block direction (the easier way to do it), the bias direction of the mesh will not offer any support.

[riggerrob 643]

So I'm curious, as someone who's been around (conventional) manufacturing for the last 30 years, what kind of quality control systems are in place in the skydiving equipment industry? And how the hell do they even check most of that stuff they build??? We have all kinds of cool technological toys to inspect the parts we manufacture at work, how the hell do canopy mfgs inspect a finished canopy after it's all stitched together? Kite it, and go... well, that looks about right?

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Human beings visually inspect every item before it leaves a parachute factory.
Those visual inspections are backed up by checking a few dimensions (ruler or go-no go gauge) that should be written on the wall above the inspection station. Then you check if the lines or harness is symmetrical and whether the final product matches the dimensions and colors on the order form, etc.
At least that is the way I did final inspections at Butler Parachute Systems, Rigging Innovations and Para-Phernalia.

[mjosparky 4]

Since a kill line main P/C is a non TSO'd item the QA could be just about anything. It is more than likely that the guy/gal the sews it looks it over before pushing it across the table to shipping. He/her may not have even seen the master drawings if there are any.

Sparky

My idea of a fair fight is clubbing baby seals

[bwilling 0]

Thanks riggerrob and mjosparky, for the insight! I think my post got picked up as a rant about the pilot chute, instead of just genuine curiosity about quality control procedures in the parachute industry that I had intended...

Having been in manufacturing for a long time, I look at something as complex as a harness & container system, or a completed canopy, and wonder how the heck you'd even check the thing when you were done with it!

"If all you ever do is all you ever did, then all you'll ever get is all you ever got."

[nicknitro71 0]

That's the reason I make my own ones.

I had a problem with what is the most popular Kill line PC out there. It was not calibrated correctly and did not collaspe all the way, not a biggy to fix but when your drop 100 bucks for a PC you'd expect to work. Now it only costs me about 10 bucks...

Memento Audere Semper

903

[riggerrob 643]

Quote

Since a kill line main P/C is a non TSO'd item the QA could be just about anything. It is more than likely that the guy/gal the sews it looks it over before pushing it across the table to shipping. He/her may not have even seen the master drawings if there are any.

Sparky

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Master drawings never reach the production floor. Master drawings (to satisfy the FAA) contain so much detail that they baffle all but a handful of draftsmen and senior design engineers.
It takes several weeks of "thinkology" to reduce master drawings to production patterns (i.e tin outlines that can be used on the cutting table).
Since master drawings contain far too much detail, go-no-go checks for final inspectors have to be reduced to a handful of dimensions (ideally drawn on the final inspection table).
The other point is that critical dimensions should be checked before an item moves on to the next step.
In other words, an item is not allowed to move from station A to station B before an inspector has signed the paper "traveler" that accompanies every TSOed item along the producition line.
... and you have to repeatedly remind production staff not to sew on top of other people's mistakes.

[mjosparky 4]

Quote

Quote

Since a kill line main P/C is a non TSO'd item the QA could be just about anything. It is more than likely that the guy/gal the sews it looks it over before pushing it across the table to shipping. He/her may not have even seen the master drawings if there are any.

Sparky

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Master drawings never reach the production floor. Master drawings (to satisfy the FAA) contain so much detail that they baffle all but a handful of draftsmen and senior design engineers.
It takes several weeks of "thinkology" to reduce master drawings to production patterns (i.e tin outlines that can be used on the cutting table).
Since master drawings contain far too much detail, go-no-go checks for final inspectors have to be reduced to a handful of dimensions (ideally drawn on the final inspection table).
The other point is that critical dimensions should be checked before an item moves on to the next step.
In other words, an item is not allowed to move from station A to station B before an inspector has signed the paper "traveler" that accompanies every TSOed item along the producition line.
... and you have to repeatedly remind production staff not to sew on top of other people's mistakes.

Like I said, this is a non-TSO'd item and all of the above would not apply. One person cut it out, sewed it together and QA'd it. (probably)

"He/her may not have even seen the master drawings if there are any."

Here again, I mentioned this to point out that are probably no master drawings.

Sparky

My idea of a fair fight is clubbing baby seals