Peter wrote:
Then you need some way to control the G upon impact. The SR22 chute achieves a vertical speed of 17kt. Dissipating this in a distance of say 0.5m (typical depth of a retractable with gear up) gives me 76g (a=v^2/2s). In the downward direction, that will destroy your spine, and do lots of other internal damage. So you have to do, ahem, what Cirrus did, to get this down to something like the 20g which has been claimed for the SR22 (can’t find the ref for that figure right now). Have a fixed gear and have special thick compressible seat bottoms. I wonder if the makers of the various non-cert designs with BRS did this calculation?
Something can’t be right here. 17 kt corresponds to a ROD of ≈1700 fpm which sounds excessive. Also, to achieve 20 g from 17 kt, you would need a stopping distance of about 2 m, which the compressible seat bottoms obviously don’t give you.
The fact is there aren’t injuries on Cirrus that land vertically. The system just works
Actually, while not the design intention: 19 aircraft were repaired to fly again
Some even had another fatal accident
https://www.cirruspilots.org/copa/safety_programs/w/safety_pages/723.cirrus-caps-history.aspx
EuroFlyer wrote:
I will never understand why Mooney didn’t invest in a BRS when they had their new Chinese investors on board and came back in 2014.
I did not understand it either. What I heard after the renewed shut down is that the “engineering was done” for the M20 series and deemed to increase the cost and decrease payload to such an extent, that the plane would be even less viable than before. This is due to the fact that the airplane would have had to be recertified fully with such a change, for which the means were not available. A figure I have heard is close to $100k additional per airframe. They opted for the improved shell and 2nd door instead, which they were able to shoe-horn into the existing type certificate.
The M10 obviously failed because it’s constuction was faulty and they just in time found that the prototype had massive bonding issues after 130 hours. Or at least that is what the rumour mill is talking about. That however a BRS was never considered for that plane is totally inexplicable.
Which, I guess, is the whole problem of the aviaiton industry. One figure I heard today incidently is that the certification cost for a simple SEP goes to roughly 40 million dollars if every thing goes right. Neither Cirrus nor Columbia did actually survive that process on their own. And it does simply not look like anyone is willing to put up these kind of money to certify a new SEP as the market is simply not there to get that money back.
Which, I guess, is the whole problem of the aviaiton industry. One figure I heard today incidently is that the certification cost for a simple SEP goes to roughly 40 million dollars if every thing goes right.
But help is on the way, no? Or is this 40 million already taking into account the following?
In a word, no.
In the past ten years I’ve witnessed – at a rough count – ten aircraft accidents and incidents, of which five were write-offs. In none of these was there any personal injury, not even a scratch or bruise. I don’t see how a parachute would have improved the score.
Advertising by Cirrus and BRS reminds me of similarly successful misinformation by manufacturers of “low tar” cigarettes. To cut through the ad agency bullshit, the NTSB database is our friend. In the years 2010 to 2018 inclusive,
Cirrus (all models): 214 accidents and incidents, of which 64 (30%) fatal.
Beechcraft A36: 117 accidents and incidents, of which 38 (32%) fatal.
Just for fun, I ran the same queries for the wretched GA peasants in the cheap (Maule) seats:
99 accidents and incidents, of which 9 fatal.
Shocking that the official kill rate is as high as 9% for such a risk-averse population as Maule pilots in what amounts to a tin parachute.
Peter wrote:
There must be reasons. What are they?There may be a structural issue.
You have to remember, all ULs can have a chute, in some countries it is mandatory. There are several hundred variants and around 50? thousand of them in Europe. It’s definitely not a structural issue, this is straight forward engineering, and the added weight is 10-20 kg, hence insignificant.
The reason could be that when studying the matter, it just isn’t worth the cost. Let’s say the added cost for a certified aircraft is 100k. Would the added sales make up for the added sales price? probably not. If Cessna started doing it, they would also signal that all their planes up until now are unsafe. People may say positive things about the chute, if they have an airplane with a chute. The thing is though, you cannot purchase a Cirrus without the chute, so we cannot know how many would have chosen a plane without the chute, given it would cost you 100k less.
If people in general really were that afraid of wings falling off or whatever, then:
It makes sense for Cirrus as a sales argument, but not necessarily for anyone else. But, that seems a bit odd as well, because for ULs people will normally invest in that chute, even if it’s not mandatory, and no one really care if there are no chute in an older plane. In a way Cirrus have managed to made it a much bigger deal out of it than it really is – for Cirrus. At the same time people just don’t care. A bit strange IMO.
I would be amazed if the cost to the manufacturer was anywhere near 100k.
Remember that an airframe manufacturer is a 145 company, with in house certification. They can buy e.g. some hydraulic part for €20 from some no-name machne shop which sells bits to antique car builders, certify it and sell it for €1000. In fact this is exactly why aircraft parts are key to survival once you no longer make and sell the aircraft itself.
I reckon Cirrus pay a few k at most for the whole chute assembly.
Maybe, but there has to be some reason why others aren’t doing it, and this has to be of economical nature.
