ZigZagMarquis 8 #1 February 19, 2007 QuoteA note. The pull test recommended/required by PD is NOT the same as PIA TS-108. TS-108 specs 40lbs and PD specs 30lbs. Some PIA members, including PD, feel that the 40 lb is too high for the fabrics used. PD is not the only one who advocated a lower test force. This is currently being discussed in the PIA Technical committee. In general, most comments I've heard at PIA meetings support pull testing ALL canopies. The debate is over the force. Some manufacturers maintain that 40lbs may damage "good" material. Another part of the debate in the other forum is whether "should" in the manual indicates that it is manditory. My interpretation would be recommended but not manditory. It has been reported that verbal conversation with PD indicates that they intend for it to be manditory. With the detail that they put in about performing and documenting the test I believe they intended it to be manditory and made a poor choice of words. In general I've been pull testing all older ram airs, plus 5 years or more, and been gradually moving to testing them all. Since I was previously aware of the force debate I've been testing to 35 lbs (another number put forward by the old PISA), except where mandated by AWD or service bulletin to use 40 lbs. I was aware that PD was advocating 30 lbs several years ago. Weak ram air canopies HAVE been found by others though I don't have the details available. Okay... I admit, I borrowed CMan's post (above) from an old 04 thread, but I thought it good base to kick-off my question... Any of y'all all fresh from the recent PIA convetion and all jacked up on safety... PD says... "Fabric testing should be done annually"... and... "apply 30lbs for 3 seconds". Okay, I'm not here to debate the use of the word should in the above excerpt from the PD Manual, but what I'd like to ask is was there any discussion of Pull Tests at the recent PIA convention? Some more specific questions... 1) What about other reserves / mfgr's other then PD? Do they recommend Pull Tests on their products? 2) PD's recommendation is different the PIA's TS-108, which is basically the same, but 40lbs for 3 seconds. Any discussion of clarifying the difference between the two? Quote Share this post Link to post Share on other sites
fcajump 153 #2 February 21, 2007 QuoteQuoteA note. The pull test recommended/required by PD is NOT the same as PIA TS-108. TS-108 specs 40lbs and PD specs 30lbs. Some PIA members, including PD, feel that the 40 lb is too high for the fabrics used. PD is not the only one who advocated a lower test force. This is currently being discussed in the PIA Technical committee. In general, most comments I've heard at PIA meetings support pull testing ALL canopies. The debate is over the force. Some manufacturers maintain that 40lbs may damage "good" material. Another part of the debate in the other forum is whether "should" in the manual indicates that it is manditory. My interpretation would be recommended but not manditory. It has been reported that verbal conversation with PD indicates that they intend for it to be manditory. With the detail that they put in about performing and documenting the test I believe they intended it to be manditory and made a poor choice of words. In general I've been pull testing all older ram airs, plus 5 years or more, and been gradually moving to testing them all. Since I was previously aware of the force debate I've been testing to 35 lbs (another number put forward by the old PISA), except where mandated by AWD or service bulletin to use 40 lbs. I was aware that PD was advocating 30 lbs several years ago. Weak ram air canopies HAVE been found by others though I don't have the details available. Okay... I admit, I borrowed CMan's post (above) from an old 04 thread, but I thought it good base to kick-off my question... Any of y'all all fresh from the recent PIA convetion and all jacked up on safety... PD says... "Fabric testing should be done annually"... and... "apply 30lbs for 3 seconds". Okay, I'm not here to debate the use of the word should in the above excerpt from the PD Manual, but what I'd like to ask is was there any discussion of Pull Tests at the recent PIA convention? Some more specific questions... 1) What about other reserves / mfgr's other then PD? Do they recommend Pull Tests on their products? 2) PD's recommendation is different the PIA's TS-108, which is basically the same, but 40lbs for 3 seconds. Any discussion of clarifying the difference between the two? I suggest that a full mfg list be made to chart this as some (PD) want it done annually, and others PISA have stated NEVER put a clamp on our canopies. I often call the mfgs to get their current read on it, but a comprehensive survey would be useful... Anyone have time? JWAlways remember that some clouds are harder than others... Quote Share this post Link to post Share on other sites
riggerrob 558 #3 February 21, 2007 As far as I know, Performance Designs are the only manufacturer of ram-air reserves who tell us to pull-test fabric. Flight Concepts recently told us not to. I have only seen holes in ram-air canopies caused by pull-testing. The first was a Safety-Flyer - built by Para-Flite before F-111 fabric was invented. The second torn ram-air reserve was a PD reserve brought to me by an embarassed, new FAA Senior rigger. I dutifully patched the hole (in the middle of a panel) and pull-tested that PD reserve in a dozen other places. My only explanation was that he had probably pull-tested on top of an earlier pull-test. We returned the canopy to service. I don't care what propaganda you may have heard about pull-testing being a "non-destructive testing method," pull-testing weakens fabric! Quote Share this post Link to post Share on other sites
ZigZagMarquis 8 #4 February 21, 2007 Interesting. Makes me wonder if I want to shell out the $150 to Para-Gear for the guchi-fied sheet metal clamps & fish scale to have a set of the stuff for my own or keep borrowing someone else's when I feel I need it. Quote Share this post Link to post Share on other sites
potvinj 0 #5 February 21, 2007 First, to recap a similar debate on the PIA riggers' forum (the thread is “canopies/Reserve Fabric Strength Testing”): 1- The 40lb tensile test of TS-108 can be traced back to a US Air Force requirement for the breaking strength of the fabric used to build the C-9 canopies, i.e. 42lbs, for MIL-C 7020, 1.1 oz. Type I nylon 2- The F-111 fabric modern canopies is rated at 45lbs according to PIA standard PIA C-44378 (Type I) 3- Note that zero-P fabric is stronger that F-111 (duh!) – see Performance Textiles’ spec for its zero-P Soar-Coat fabric is rated at 47lbs (http://www.perftex.com/milpara.htm). I understand the reluctance by many to use the 40lb test on fabric that is rated at 42lbs, being so close the rated failure point. A lower pull test force, say 30lb or whatever, seems more palatable. BUT! A canopy that passes a 30lb tensile test is still un-airworthy if it fails the rated breaking point of its fabric (be it 42 or 45 or 47lb). Were does a 30lbs test leave us riggers???? In a way I like the idea of parachute manufacturers mandating a maximum pull test force in their packing instructions. The issue of pull-testing then becomes an issue of following a manufacturer’s packing instructions. Here the “airworthiness” issue that the FAR mandates us riggers to uphold then hinges on what the manufacturer thinks is airworthy, not on a given rated fabric strength. Jean Quote Share this post Link to post Share on other sites
