One of the possible horrible situations for which an airframe parachute would be great is loss of control in IMC. I know this SHOULDN’T happen, but it sure seems to happen enough. There are equipment failures that can cause even a good pilot to lose control. While it’s one of the least likely things to happen to a conscientious pilot, it would probably also rank as one of the most horrifying.
I know the BRS was only certified to deploy at some speed below red line (I can’t remember what), but does anybody know if any informal testing of the system was done at higher speeds, such as those that would be found in a spiral dive?
I know the BRS was only certified to deploy at some speed below red line (I can’t remember what), but does anybody know if any informal testing of the system was done at higher speeds, such as those that would be found in a spiral dive?
Jonathan,
I could be wrong, but I believe that the maximum speed at which deployment has been demonstrated is 133 KIAS. Certainly, whatever the maximum speed is at which testing has been done, if I’m in trouble at a higher speed (like in the spiral dive that you suggest, or watching the ground coming up at me rapidly after losing an important bit after a mid-air collision, etc.), I’m going to activate the CAPS, and damn the torpedoes. Then, if I survive, I’ll be attacked by an angry mob of COPA members; for mixing metaphors in cruel and unusual ways.
Thanks for the responses, everbody. Very educational. I didn’t realize that the chute was designed to operate even if the delay mechanism fails. I figured that if it needed one, then there wasn’t much margin for safety in an overspeed situation. I’m glad to hear that I was wrong, since the chute’s usefulness would be severely limited otherwise. If things are going so badly that you need the chute, then there’s a good chance you can’t be picky about your airspeed. (I imagine you get going down pretty quickly after a midair.)
I think I remember reading somewhere that before CAPS was tested on a plane, it was tested by hitching the chute to barrels of sand pushed out of the back of a transport plane. I seem to recall that under those circumstances it deployed at a much higher airspeed than 133 kts. Of course, even if this is true, it doesn’t mean that it would work that way in a terminal dive. But at least you’d have a chance of living to face the metaphor police…
I believe the CAPS will work at higher speeds but there is a mechanism within the CAPS which lowers the opening shock. If this system fails, the shock would probably be very dangerous. Since there is no redundancy to this system, it is certified at the lower airspeed.
From a totally practical perspective, if you find yourself in a ‘death spiral,’ suffering from vertigo with ever increasing airspeeds, what choices do you have? Can you manually recover the plane? Doubtfully, if you had the faculties to recover, you probably would have avoided that situation, just ask JFK. So what other choice do you have? Pull the CAPS handle and hope for the best!
Since the next question will be about the part of the CAPS which reduces the opening shock, I’ll try to answer it but please excuse me if I miss every technical term. Also, this explanation was based upon one conversation years ago, so a few details may be fuzzy as well.
First, think of the Apollo space capsules returning to Earth. When they first appeared on TV, there would be three parachutes, but they looked more elongated than normal. This was a partially open situation, where the opening was constricted by a retaining ring holding the risers (lines) of the parachute from spreading out. Then, all of a sudden, the three parachutes would open to their full volume. This occurred because the sliding retaining ring ‘slides’ down the risers and allows the parachutes to open fully.
Well, the CAPS has a similar mechanism, as i understand it the slider is held up by the airflow pushing it up the risers and the parachutes are trying to open and push it downwards. As the speed decreases the parachutes are able to overcome the wind force and push the slider down and all the parachutes to open fully. Unfortunately, if this mechanism were to fail, the ride will be well beyond the “E” ticket ride promised.
To see what Marty is talking about, you can watch the CAPS deployment videos available here: http://www.airplaneparachutes.com/BRS35.htmHere is a link to the US Patent held by BRS for the mechanism Marty described. (If that link doesn’t work, go hereBRS’s web site.
This “slider” works on simple gravity. When the weight of the slider overcomes the higher speed in deployment, it slides down the risers and the parachute opens fully.
Yikes! Watching the Cessna 150 high speed deployment gave me a sense of the dramatic change in attitude from level to almost vertical nose up. Quite a pendulum effect! What a wild ride! Interesting that with the Cessna videos I could not see the clever 8-second delay we have in adjusting the risers from slight nose down to horizontal attitude – those pesky explosive bolts that have a shorter life span than the parachute. Any insights from BRS folks?
Does anyone know what the gross weight was for the CAPS tests for certification? I would think it would have to be max gross. It would seem like there would be more margin for speed when the weight is below max gross. This could get too academic, but it is a little reassuring.
In any case, in a real CAPS type emergency I would certainly try to get as slow as possible before pulling the chute. However, if I can’t slow down, the chute is going to be out before I get to the ground.
If my memory of what I was told serves correctly, the CAPS was tested at weights higher than max gross, during the tests where barrels where pushed out the back of a plane - I remember the figure of 3400lbs being mentioned… The SR20 tests would certainly have been at max gross or higher, that would have been essential for certification.
Just to add one more thought to this thread… I believe that in many of the situations in which CAPS deployment would be appropriate are also the situations that suspend normal brain operation (at least for me). I have long since decided that when I’m truly scared or surprised or dazed or (synonyms of your choice), about the only things I manage to do are those which have become reflex actions.
For that reason, when I fly solo, I’ll sometimes say “BANG” and then reach up for the handle with a closed hand… to “practice the move”, as it were, without risking actually pulling anything (closed hand). When I do it, I don’t look up – I might need to do this at night, in a dark cockpit. I don’t practice this with passengers on board, for obvious reasons.
“Practicing the move” is particularly interesting in turbulence - it’s harder than I realized; and in a “real situation”, I might have significant G forces to fight as well. Actually, it’s this exercise that has led me to fly with the CAPS cover removed and safety pin pulled - something I didn’t do before. Removing the pin is on my startup checklist, and putting it back is on my shutdown checklist.