Stawell crash
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I have seen most of the spin testing which they’ve done and I am satisfied. It seems like more of a documentarian problem that CASA are concerned with particularly as it relates to the diferent models long wing vs short wing vs tail dragger etc. One of the complaints relates to the Roko Spol which was the forerunner to the Bristell and has been out of production for about 10 years with the manufacturer having gone broke. Retesting and proper documentation would probably solve it. The rules around LSA are very complicated and not well understood. CASA seems to take a lot of unprecedented actions and are well on the way to destroying GA in Australia.
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I would never spin my Bristell . The POH says not to and to do so would break CASA’s rules. I have stalled it many times though with not a hint of trouble. It must be properly rigged though with the rudder cables correctly tensioned .
I heard somewhere that in certain overseas they are required to be fitted with a BRS. Would love to know if that was true.
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Especially if you are a student high on Fentanyl being taught by an inexperienced instructor who didn’t expect it to happen, or alternatively a low time pilot showing off to your passenger and people on the ground with extreme manoeuvres. Surely a recipe for disaster in both cases don’t you think?
So you’re saying they are a high performance aircraft, not suitable for a low time pilot?
I’m not defending the aircraft or the CASA actions, however something strange is going on somewhere... it does pass the sniff test.
I’m not defending the aircraft or the CASA actions, however something strange is going on somewhere... it does pass the sniff test.
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As a purchaser of any new or used aircraft, I would reasonably expect that if I was to spin the aircraft, either intentionally or unintentionally, that I would, with reasonable piloting skills, be able to exit the spin using normal recovery techniques, or as modified and documented in the POH.
That should be the litmus test in reality, but it appears that proving this is an issue.
That should be the litmus test in reality, but it appears that proving this is an issue.
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I would imagine that’s exactly what the ASTM standards are about. The Bristell has been spin tested extensively by a Russian test pilot who works as an engineer and test pilot testing the Sukoi S35 fighter. He also happens to be a Bristell owner. For various reasons some of which have been specified and some not , CASA do not accept this testing and have asked for it to be redone by an independent organisation. As I said previously a lot of it is around documentation and extrapolation from one model to another which CASA do not think is appropriate. Perhaps I should mention the letter came from CASA’s Manager of Stakeholder Engagement for goodness sake. That had me puking before I started reading . There is a lot more to come out in this matter yet including a proper investigation of some unofficial spin testing possibly carried out at the behest of RAAUS in the Latrobe Valley a couple of years ago which is referred to in previous posts and which probably broke several CARs.
Ng5:
.....And therein lies the problem.
The aircraft does not appear, in CASAs view, to be capable. of reliable spin recovery by an ordinary pilot and certainly not drug users or the testosterone fuelled.
The Bristell has been spin tested extensively by a Russian test pilot who works as an engineer and test pilot testing the Sukoi S35 fighter.
.....And therein lies the problem.
The aircraft does not appear, in CASAs view, to be capable. of reliable spin recovery by an ordinary pilot and certainly not drug users or the testosterone fuelled.
He said, she said... yadda, yadda, yadda
They just didnt test properly or comply with the ASTM requirements.
I served on the F37 committee for about 4 years and know shortcuts taken by some manufacturers because they used to stupidly boast about them, including signing off other model variants (nosewheel versus tailwheel, short wing versus long wing etc) because they just didnt want to do the work. Many also tested spinning at the 472.5 kgs European limit and then declared compliance at 600 kgs without any additional testing.
There are 600 test points as part of proper spin and recovery testing and each must be completed 3 times safely.
I cant post the requirements here for ASTM copyright reasons.
Lest just say, regardless of who was flying the plane during testing that this any many other manufacturers didn't meet the testing requirements for spinning and many other requirements and this is a big issue with manufacturer self-validation. The manufacturer can say anything up until they are asked to validate the compliance with the standards and the problem comes when they cant validate as has happened here.
They just didnt test properly or comply with the ASTM requirements.
I served on the F37 committee for about 4 years and know shortcuts taken by some manufacturers because they used to stupidly boast about them, including signing off other model variants (nosewheel versus tailwheel, short wing versus long wing etc) because they just didnt want to do the work. Many also tested spinning at the 472.5 kgs European limit and then declared compliance at 600 kgs without any additional testing.
There are 600 test points as part of proper spin and recovery testing and each must be completed 3 times safely.
I cant post the requirements here for ASTM copyright reasons.
Lest just say, regardless of who was flying the plane during testing that this any many other manufacturers didn't meet the testing requirements for spinning and many other requirements and this is a big issue with manufacturer self-validation. The manufacturer can say anything up until they are asked to validate the compliance with the standards and the problem comes when they cant validate as has happened here.
Stickshift, thanks for putting things right, that's the problem with the 'net and assuming what is said is correct, y'tube had it listed as "Bristell flat spin". The video here tells you it was a Skytrek from the panel layout (1:24). Given the design elements of both aircraft it would seem evident that they both have the same parent. The Skytrek manufacturer does say "The Triton Skytrek is the first CAAC and FAA-certified factory-built Light Sport Aircraft made in China! It shares the same heritage as the likes of CZAW SportCruiser, the PiperSport and some other look-alike that are derivatives of the ZenAir 601XL"
Last edited by megan; 2nd Aug 2020 at 02:42.
The ASTM LSA guidance material that I have seen refers to the FAR 23 Flight Test Guide so the applicable nominal spin matrix is this one. Cross out the items not applicable. AC 23-8C has some associated notes which are relevant.
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Stickshift, thanks for putting things right, that's the problem with the 'net and assuming what is said is correct, y'tube had it listed as "Bristell flat spin". The video here tells you it was a Skytrek from the panel layout (1:24). Given the design elements of both aircraft it would seem evident that they both have the same parent. The Skytrek manufacturer does say "The Triton Skytrek is the first CAAC and FAA-certified factory-built Light Sport Aircraft made in China! It shares the same heritage as the likes of CZAW SportCruiser, the PiperSport and some other look-alike that are derivatives of the ZenAir 601XL"
https://www.youtube.com/watch?time_c...ture=emb_title
https://www.youtube.com/watch?time_c...ture=emb_title
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Further potential issues coming to light with the actual CoG measurement Vs handbook datum measurement:
https://www.australianflying.com.au/...r-bristell-cog
https://www.australianflying.com.au/...r-bristell-cog
Further potential issues coming to light with the actual CoG measurement Vs handbook datum measurement:
https://www.australianflying.com.au/...r-bristell-cog
https://www.australianflying.com.au/...r-bristell-cog
There is no Type Certificate Data Sheet with moment arms which I'd use when doing weight and balance for a certified aircraft. If not certified I would check measure stuff like that myself. POHs can have typos.
The Super Decathlon's AFM had an error in crew moment arm from 1995 until a SL in 2018. That error also pushes the real CG further aft - just the rear seat moment arm and the change is about half that of the Bristell. CASA's role in that is interesting too but a topic for another thread maybe.
http://flighttestsafety.org/images/s...in_Testing.ppt
If a company has already been through a development spin test program and an authority wants to see a report to show compliance then it may only get the data required to show compliance. It would be interesting to look at the CT-4 spin test report that CASA wanted for their certification of the civil registered aircraft going to Tamworth many years ago. The original spin test report was not available. The company test pilot had spun every aircraft off the production line over many years. ARDU had done comprehensive spinning tests for the first RAAF aircraft. How does the scope of that CT-4 report for CASA (for intentional spinning) compare with the Bristell report (not for intentional spinning)? CASA also has a copy of the Pitts S-2A spin test report that they may care to look at too (back then they wanted all the data, now they accept FAA certification so they haven't seen the reports for later models) - it has far fewer test points than the Bristell and it includes inverted spins too.
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Aft C of G issue
2-up using the book moment for pilots may result in a CofG well aft of the limit - this may explain the many flat spin accidents with this type..
https://gasci.weebly.com/new.html
https://gasci.weebly.com/new.html
