Learn to fly the plane and you will never have to deal with either scenario. Sr22’s even at full gross get off the ground quick so if you aborted you would have more than enough runway to stop. Aim for the numbers and scenario 2 won’t happen.
Yes they do!
Hi there…
from the pilots view you are right, however - even Cirrus engines may develop technical problems in critical flight phases
- add that to short field OPS as they are more common in Europe (
I would say the average runway length in the US is 4 to 5 thousand feet for small airports. I have landed at some in the 2800 to 3000 ft. I could see scenario 1 at a high altitude runway. What runway lengths are you dealing with in Europe?
That’s what I wanted to point out: Most of the GA airstrips have 2000-3000 ft, some even less (please google for airfield EDXH, which is used by SR22), many of them w grass surface.
What we call “bigger” has 3000 ft +. So most airstrips are below that. Also there are some SR20 flying around here.
Most of the fields I fly out of are 100ft elev or less and all are paved. 2,000ft is no problem under those conditions. I have never actually used a soft field and, depending on your elevations, that could get to be very challenging at max gross in a 20
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Cirrus’ official position is that if you are ever faced with a situation where catastrophic injury or loss of life would be imminent due to collision with the ground, obstacles, or both, you should deploy the CAPS.
The reason has to do with energy.
You can look at landing an airplane as principally a problem of energy dissipation. A flying airplane has two different kinds of energy relative to one sitting on the ground in the form of potential energy, related to how high it is from the ground, and kinetic energy, which is proportional to the square of its velocity (groundspeed) which added together gives the total energy state of the airplane. A normal approach landing will gradually dissipate this energy in a controlled and safe manner which does not damage the airframe or injure the occupants. This dissipation normally occurs through induced and parasite drag forces acting over a distance, minimazation of thrust forces by reducing your throttle settings to idle to prevent adding additional kinetic energy to the airframe, and dissipation through the brakes via heat.
Now if a crash is imminent and there is no way out, the a/c energy stat will be reduced to zero either through the destruction of the airframe, deformation of the ground and or obstacles upon impact or injury to your little pink body. The trick here is that prior to impact you want to get that energy state as low as possible. Deploying the CAPS, no matter what attitude the aircraft is in or what stage of CAP deployment is attained at the time of impact, will do this. It will minimize your speed at impact reducing deceleration loads on the aircraft and occupants and increase your chances of walking away from the accident.
Be advised: this is not to say it will be totally effective here and these are extreme scenarios where, no matter what, you are still in a world of sh*t and it is highly likely you will be seriously injured or killed. It’s just that CAPS could give you and extra edge and reduce the risks to you and the crew even further.
What do experts thing on “ground loops”? EG spin it via brakes? Not sure of benefit, but oft discussed…
This is about the most intelligent thing I’ve read on this topic, thank you for articulating this.
If you are heading toward something hard, with no other option, your primary goal should be to dissipate energy. I concede there is an altitude where the pendulum swinging of the plane might make things worse, so I agree it might make sense sometimes not to pull.
But it would be insane NOT to pull the chute if you were actually on the ground – or maybe a few feet above it – and heading toward a bad outcome. Those who say the chute is not effective because it takes a while to deploy are misunderstanding physics. Everything matters, because impact forces are exponentially affected by speed. Certainly it is true that the chute deploys gradually. But it creates drag at the very instant it emerges. Five knots of airspeed decrease might save your life.
Pulling the chute on the ground is unlikely to help due to the long delay before it opens up. In 8 seconds, history will have been written. However, reaching for CAPS may distract the pilot from giving control of the aircraft their undivided attention.
Above 5 feet but below 400 feet, the chute could turn an aircraft under control into a stall/crash with warning.
Fighting with every thing you have is always Admirable. Pulling the chute on the ground means you have already made three or four fatal mistakes. To ask the question that if I have screwed the pooch and should I fix that? Then by all means Do the things that will make you more safe. If you are asking the question now, then don’t put yourself in the position to pull the handle on the ground.
The obvious answer is GO AROUND. If that’s not an option, then DONT LAND. Aviation is a business that doesn’t tolerate mistakes. Never plan on making fatal errors. Plan on avoiding then. If you find yourself in one, then trust your life to your reflexes.
Surprised nobody mentioned turning off the mags? I would stand on the brakes, apply full up elevator, and then if I had time to reach for something with my right hand… I would turn the key to OFF.
See my third post in this thread.
Carlo,
Maybe it’s just me, but your description of Cirrus’ official position seems inconsistent with what the OP pasted from an e-mail response he received from Cirrus. That e-mail warned about adverse consequences of a pull only a few feet above ground.
In fact, in transition training, I was drilled on emergency engine shutdown procedures in the event I was about to overrun the end of the runway. That was a few years ago. So, if you’ve had more recent transition training I’d be interested in learning the new procedure being taught. Where is that described - a new training video perhaps?
Thanks
It is on Cirrus’s website. Under CAPS guide. Says: “Whenever a pilot is in a situation in which no other survivable alternative exists, CAPS should be activated regardless of altitude.”
But even if it did not say this, we need to put this to bed, the answer is obvious. This reminds me of the non-data-driven OWT’s of ROP, or those who used to say CAPS would not work below 900’. Killer posts.
Any drag matters. We can discuss how many angels fit on the head of a pin, or wild scenarios where it would be more harmful to pull it on the ground than not to, but this is not enhancing safety. If you are on the ground, heading toward a bad outcome, and not crossing through a pool of avgas, don’t be an idiot. If you are too busy to pull because you need to keep your attention focused on something, then such is life. But don’t make this be your base case.
It is too late tonight, but I will lay out the data to support this clear conclusion at another time. In sum, that gigantic parachute slows the plane in very, very little distance. That’s not my opinion, it is a fact. While the analysis is not apples to apples due to horizontal vs vertical speed, the chute slows it from 100 to 20 in about 400 feet, if it is fighting gravity!
Imagine if I were landing sideways on a runway at RDU, going 100 – by the time I crossed the runway and got to the taxiway, I would be going about 20. . . if my brakes didn’t work. Or, if I landed at the very end of the runway, going the wrong way, I might hit the first runway light going about 20. Alternatively, I could comply with some other paradigm and hope.
I know this analysis is rough, so pardon my sloppiness, but I just had to drive a stake through this. Not your post, Mark, but the broad set who say it is not usable on the ground.
Wouldn’t it be easier to just pull the mixture knob to idle cutoff? Achieves the same thing and is more natural since we reach for the red knob all the time.
The Cirrus graphite airframe, unlike that of cars or tin can aircraft, does not deform on impact. It may break however. It’s strength can actually be a negative safety factor, because on impact the nearly instantaneous deceleration forces would be transmitted to the occupant as his/her pink/brown/red/unspecified body impacts the restraints that are rigidly fixed to the airframe. Seat belts work in cars because they couple the occupant to the slow(er) deformation of the frame of the car. Cars are now actually designed to slowly crumple in an engineered way. So impacting a tree at 35 mph in a Cirrus is potentially much worse that hitting the same tree at 35 mph in a Volvo.
The whole scenario is interesting but it takes too much time to recognize the seriousness of the situation and process the decision to pull the chute and then have the chute open enough to make a difference.
Scott, in the scenario I discussed, we are talking about a CAPS deployment knowing full well that full chute deployment and safe impact speeds will not be possible. Remember, if we could avoid it we would have the altitude available to us for a complete CAPS deployment or not even be flying in the first place. However since in this scenario a crash is inevitable and we have painted ourselves into a corner in which it cannot be avoided due to altitude, terrain, etc., the question becomes do you want to hit the ground at 90 kts or at 60 kts with less than half the impact energy? A partial CAPS deployment might give you that margain and possibly save your life.
Regardless of the material, be it a sheet steel frame of a car or a glass fiber fuselage of a Cirrus, the goal prior to impact is to reduce the impact speed and consequently the impact energy as much as possible. This isn’t a perfect plan; what’s about to happen is probably going to hurt - and hurt really bad. But our priority at this point is to stack the odds of living through it as much in our favor as possible. The only other alternative left is a fatal impact into terrain. Take your pick.
Carlo & Tom:
please see the clear statement from a Cirrus Rep posted here on 5 Feb.
I guess he wants to prevent something like this:
Physics of forces are clear, however I think opposite to the almost reflexive pull above 500´ one should be very cautios below. A big chute pulling my tail straigt might also prevent me from any directional control on the ground.