There were a few posts awhile back (Mar. 6-7) speculating about the best position to have the seat for the impact following CAPS deployment.
Dr. Baehr’s opinion was “I would think being as flat as possible {on your back} with arms crossed over chest would be the best position to hit, IF coming down with little horizontal momentium. The more upright you are the more you would tend to load your spine on impact.”
Others wondered whether the seats would be strong enough in the more reclined position, etc.
There are other variables, too; but I asked Cirrus directly about the seat strength in different positions. The response was “We constructed the tests so that all seat positions showed a pass.” I assume that means that the seat really is safe in all positions.
Cirrus had no official comment on the best position for the seat, citing the many variables that would influence the best choice in different situations.
For me, if I ever deploy the CAPS, and have nobody sitting behind me… and, if I have enough functioning brain cells to think… I’ll opt for the most reclined position I can get.
Mike.
FWIW, I remember reading somewhere that military ejection seats always keep the pilot’s spine aligned to the direction of the acceleration (ie, upright). The effects on the spine of rocketing upward at high G forces should be similar to the effects of impacting the ground at high G forces – same spinal compression in the same direction. ItÂ’s understandable that Cirrus wonÂ’t expose itself to liability by making recommendations, but the military doesnÂ’t seem to have that problem. Maybe some reader of this forum has some ejection seat experience, or knows someone who does.
There were a few posts awhile back (Mar. 6-7) speculating about the best position to have the seat for the impact following CAPS deployment.
Dr. Baehr’s opinion was “I would think being as flat as possible {on your back} with arms crossed over chest would be the best position to hit, IF coming down with little horizontal momentium. The more upright you are the more you would tend to load your spine on impact.”
Others wondered whether the seats would be strong enough in the more reclined position, etc.
There are other variables, too; but I asked Cirrus directly about the seat strength in different positions. The response was “We constructed the tests so that all seat positions showed a pass.” I assume that means that the seat really is safe in all positions.
Cirrus had no official comment on the best position for the seat, citing the many variables that would influence the best choice in different situations.
For me, if I ever deploy the CAPS, and have nobody sitting behind me… and, if I have enough functioning brain cells to think… I’ll opt for the most reclined position I can get.
Mike.
I think the best position depends a lot on the position of the harness’ anchor points in the fuselage relative to the human body. You will recall that the harness goes over both shoulders and around the waste. For instance, if you recline and the anchor points are now forward of your upper body, your body would have to take up this slack before the harness stopped your forward momentum. This is an extreme example, just to make the point.
There were a few posts awhile back (Mar. 6-7) speculating about the best position to have the seat for the impact following CAPS deployment.
Dr. Baehr’s opinion was “I would think being as flat as possible {on your back} with arms crossed over chest would be the best position to hit, IF coming down with little horizontal momentium. The more upright you are the more you would tend to load your spine on impact.”
Others wondered whether the seats would be strong enough in the more reclined position, etc.
There are other variables, too; but I asked Cirrus directly about the seat strength in different positions. The response was “We constructed the tests so that all seat positions showed a pass.” I assume that means that the seat really is safe in all positions.
Cirrus had no official comment on the best position for the seat, citing the many variables that would influence the best choice in different situations.
For me, if I ever deploy the CAPS, and have nobody sitting behind me… and, if I have enough functioning brain cells to think… I’ll opt for the most reclined position I can get.
Mike.
Impact in a fully reclining position with any significant wind-driven forward momentum would probably result in what some firefighters call a “submarine” in a car accident, with the patient sliding through the restraint system and folding up under the dash. This can occur at even low speed head-on collisions, and typically results in lower extremity injuries, pelvic injuries, and foot entrapment in the pedals if the patient is lucky, strangulation from the shoulder belt if they are not. IÂ’m not sure what would happen with the SR20 harness system, but I think I would rather take the vertical component on my most padded body partÂ… and the horizontal component on the very nice harness, and walk away with a sore back. I have participated in well over 100 technical extrications in the past 20 years as a firefighter/medic, and it can take tens of minutes to get somebody out from under the dash with the best tools, techniques, and personnel. Imagine trying to get out of your crushed SRxx with your little bity rescue hammer with a hot engine and gallons of high-octane fuel on the ground, and two broken kneesÂ…
Phil Bennett
N255DD, SR20 #1095
There were a few posts awhile back (Mar. 6-7) speculating about the best position to have the seat for the impact following CAPS deployment.
Dr. Baehr’s opinion was “I would think being as flat as possible {on your back} with arms crossed over chest would be the best position to hit, IF coming down with little horizontal momentium. The more upright you are the more you would tend to load your spine on impact.”
FWIW, I remember reading somewhere that military ejection seats always keep the pilot’s spine aligned to the direction of the acceleration (ie, upright). The effects on the spine of rocketing upward at high G forces should be similar to the effects of impacting the ground at high G forces – same spinal compression in the same direction. ItÂ’s understandable that Cirrus wonÂ’t expose itself to liability by making recommendations, but the military doesnÂ’t seem to have that problem. Maybe some reader of this forum has some ejection seat experience, or knows someone who does.
I certainly have no ejection seat experiance,but, to take it one step further, if we look back to the early space programe, all splashdowns occured in the recumbunt position. Without a 5 point restraint,however, sliding forward may be a problem. For me if the seat is able to withstand a crash in any position, I will be flat on my back. Mike #396
Impact in a fully reclining position with any significant wind-driven forward momentum would
Why would the momentum be forward?
When your drifting down under the chute your relative velocity to the wind is zero so your plane won’t have any means of pointing in any particular direction. (I think) As I see it your plane will be rotating about the centerline and the direction you hit the ground in will be somewhat random. (I think)The horizontal velocity will be equal the wind velocity and the vertical velocity will ~ 25 fps (what ever is adertised).
The seat looks like it is designed to crush right under your Butt. If your laying flat you wont be able to effectively use this design feature. Skydivers land on their legs with their knees bent and use their muscles for impace attenuation.
Picture trying to land with your knees locked or flat on your back when your skydiving.
Sitting bolt upright is the way I’ll do it if i need to.
Just another point of view.
probably result in what some firefighters call a “submarine” in a car accident, with the patient sliding through the restraint system and folding up under the dash. This can occur at even low speed head-on collisions, and typically results in lower extremity injuries, pelvic injuries, and foot entrapment in the pedals if the patient is lucky, strangulation from the shoulder belt if they are not. IÂ’m not sure what would happen with the SR20 harness system, but I think I would rather take the vertical component on my most padded body partÂ… and the horizontal component on the very nice harness, and walk away with a sore back. I have participated in well over 100 technical extrications in the past 20 years as a firefighter/medic, and it can take tens of minutes to get somebody out from under the dash with the best tools, techniques, and personnel. Imagine trying to get out of your crushed SRxx with your little bity rescue hammer with a hot engine and gallons of high-octane fuel on the ground, and two broken kneesÂ…
Phil Bennett
N255DD, SR20 #1095
There were a few posts awhile back (Mar. 6-7) speculating about the best position to have the seat for the impact following CAPS deployment.
Dr. Baehr’s opinion was “I would think being as flat as possible {on your back} with arms crossed over chest would be the best position to hit, IF coming down with little horizontal momentium. The more upright you are the more you would tend to load your spine on impact.”
You guys have certainly given me food for thought. I think that perhaps I will stay upright, given what you’ve said.
Thanks.
Mike.
"and it can take tens of minutes to get somebody out from under the dash with the best tools, techniques, and personnel. Imagine trying to get out of your crushed SRxx with your little bity rescue hammer with a hot engine and gallons of high-octane fuel on the ground, and two broken kneesÂ… "
Phil Bennett
N255DD, SR20 #1095
You just gave another reason, beside economics to have a modern Jet A engine, like the MR305, fitted on our Cirrus !
Jaap J. Dito MD
The chances of landing in a perfectly flat attitude are almost nil. If the tail hits something first, like a power line or a tree, your going in the rest of the way on your nose and vice versa. You hit a roof and slid off in what attitude will you hit?. Stay upright in the seat tighten the belts as tight as possible and put your hands along your face with fingers over the eyes and the thumbs covering your jugular. You might consider unlocking the door to keep it from jamming but that’s another discussion.(Many hours sittting on an unused ejection seat and one crash landing.)
Hi Bob,
Although I would agree in most planes (Cessnas, Pipers, etc.) that it’s a good idea to open the door slightly prior to impact to prevent it from jamming shut – especially planes like cherokees with only one door! – I was told that in the Cirrus it’s probably not such a good idea. The doors, given their size and thickness, actually contribute significantly to the structural integrity of the cabin, and so it might be a better idea to leave the doors closed & locked, and rely on the hammer in the event they are jammed.
Of course, you could argue that post-impact, if you’re injured it might be difficult to have the state of mind and physical strength to use the hammer, and that would be a good point. I’m just repeating what I’ve been told…
Steve
BTW, hopefully in the next couple weeks I can make that trip out to LBE for lunch! 
Stay upright in the seat tighten the belts as tight as possible and put your hands along your face with fingers over the eyes and the thumbs covering your jugular.
Bob,
I assume fingers over eyes to protect them from shards of whatever… right? Thumbs covering jugular for the same reason? Makes sense, but I’ve never heard that before.
I have heard that it’s good to brief passengers (and yourself, if applicable), to remove false teeth, contact lenses if there’s time, pens from shirt pockets, and so on.
You might consider unlocking the door to keep it from jamming but that’s another discussion.(Many hours sittting on an unused ejection seat and one crash landing.)
I also heard the same as Steve Lin - that the SR2X door contributes significantly to the structural integrity of the cabin… that’s why they provide a hammer. Kara also pointed out that if we need to use the hammer for egress, we should strike the corners of the windows - hitting in the center would likely just make a noise.
Thanks for sharing the lessons of survival. Where/when/how was the crash landing?
Mike.
Whoa, LBE (Latrobe aka Arnold Palmer Regional) is an identifier that catches my eye! I grew up in Latrobe.
Beltz, G. (SR20 #266)
BTW, hopefully in the next couple weeks I can make that trip out to LBE for lunch!
I have heard that it’s good to brief passengers (and yourself, if applicable), to remove false teeth, contact lenses if there’s time, pens from shirt pockets, and so on.
Where/when/how was the crash landing?
Do remove pens and other objects that can harm you, like false teeth in wich you can choke. But don’t remove your contacts. You want to keep seeing what you are doing…
Keep it safe,
Jaap J. Dito MD