Interesting analysis, LeSving.
The 9g is in the right ballpark, it would appear.
However I don’t think one can assume the avionics will be OK after this, because individual items inside the boxes may not be subject to a nice steady half-sinewave peaking at 9g. Any looseness can easily take the instantaneous value to 100g or 1000g.
I have seen electronic instruments dropped from say 30cm onto a bench and it created a barely-visible crack across a large PCB. In one case we bought the item from the insurance company (for next to nothing) and paid a youngster trainee to spend a few days soldering little wires across every single track, bridging the crack 
Does anyone know what that SR22 which was chuted in Slovenia is going for?
complex-pilot wrote:
Either need a bigger chute, or a lighter aeroplane.
I think the falling velocity is as low as it gets. It is lower than a normal parachute. What is wrong in my opinion can be seen in the video. It bounces back up into the air, and it does it rather violently. With a proper damping in there somewhere, this bouncing would be zero, and the max acceleration could be reduced to less than 5g. Is it worth making a proper gear? I mean, how often do these aircraft fall on flat land?
Hmm, what would have happened if they partially impacted the building end fell down sideways the last 3-5m?
They got really lucky they landed where they landed …
How feasible is a ‘flare’ system for a parachute? Basically, just before impact, pull really hard on the line, pulling against the air trapped below the parashute and slowing down the touchdown velocity, ideally to next to nothing…
Quote from Diamond Aviators Net:
“I read somewhere that a Cirrus under parachute descends at around 1300 fpm.
In contrast, a DA40 in “parachute mode” (closed throttle or dead engine, stick held all the way back, descending in a full stall with minimal rudder use to keep wings level) descends at around 700 fpm. For those of you who haven’t tried this, it’s worth learning (like all stalls, please practice at 3000 ft. AGL or above).
Of course a parachute mode DA40 still has a forward velocity component of 40+ knots generating additional energy that must be dissipated when the aircraft hits the ground. But the DA40 pilot still has steering control of what the plane will hit, unlike the Cirrus. And the Cirrus landing under a real parachute will also have some non-zero horizontal velocity component caused by the wind."
LeSving wrote:
parachute
Velocity is one thing, the other is to dissipate the stored energy on impact.
Lighter is always better, of course.
The energy left is clearly huge as the video demonstrates, Cirrus must have built in lots of crash energy absorbing zones. Quite an achievement in my opinion, that is easily over looked.
In my opinion, a chute is the best survival option for passengers in this aircraft.
It could be argued that the same survival benefits can be gained in most emergency situations when in a much lighter, slower landing aircraft flying over a very densely populated Europe.
@Jean One has to remember that Cirrus was designed to hit the ground in a helicopter-like fashion. Hence the “26 g seats”, like in a helicopter. DA40 wasn’t. It was designed for traditional emergency landing. I would expect the risk of back injury to be significantly higher if you attempt to land this way, even if the vertical speed is half that of a Cirrus.
Jean wrote:
In contrast, a DA40 in “parachute mode” (closed throttle or dead engine, stick held all the way back, descending in a full stall with minimal rudder use to keep wings level) descends at around 700 fpm.
That is correct. I have done that. It is very impressive. The only thing is that you need to keep it coordinated, otherwise you risk dropping a wing.
I think most SEPs descend at about -1000fpm ie 10kt VS.
The gotcha is of course the forward component 
Completely agree. It’s not the vertical speed that kills in a forced landing gone wrong – it’s – probably in that order – obstacles when you come short, low-height stall, and making a runway that is too short. When instructing, I impress that it is much better to crash at the end with 10kt than in the undershoot at 60.
complex-pilot wrote:
Cirrus must have built in lots of crash energy absorbing zones. Quite an achievement in my opinion, that is easily over looked.
A bit, but nothing really remarkable. They have the landing gear (reasonably sturdy, but not really revolutionary – I am sure you can find C172 landings where the gear ends up doing something similar), the seat frame, and a honeycomb metal below the seat cushion, which makes the seats a bit hard.
What people frequently overlook is that kneeling on the seats does compress that honeycomb and make the aircraft slightly less crashworthy.
Cobalt wrote:
It’s not the vertical speed that kills in a forced landing gone wrong – it’s – probably in that order – obstacles when you come short, low-height stall, and making a runway that is too short.
I would have thought that low height stall is the N#1 killer, the other two most often end in bent airplanes, but not fatalities.
Which brings me to one of my PET-PEEVES:
I’m SHOCKED at how many pilots do not don the shoulder harness (when installed) on legacy acft , during TO/Landing !
It’s not only a LEGAL REQUIREMENT (FAR 91.107) but it’s just plain stupid not to … The typical response when I bring it up is “ah, it won’t make any difference in a real crash” , but th fact of the matter is that REAL crashes are for the VAST MAJORITY, survivable if you don’t hit your stupid head on the the control wheel or on that new EFIS !
