I never even knew these things existed until reading this news story! What is the size limit on how big a plane can be before these entire plane parachutes become impractical?
Engine failure forces pilot to parachute after takeoff in North Lauderdale
Here’s a pic of one in action I DL’d from the parachute companies website
I remember seeing this on TV a long time ago, and someone calculated it would take 750 parachutes or so to safely land a 747. Not sure of the accuracy of this calculation, but a plane that heavy going that fast would definitely require a lot to slow it down without ripping the chutes.
You’re looking at small, up to 4 seat, single engine aircraft.
According to the company’s website Their heaviest model is on a Cirrus, tested at 3600 pounds and 165 knots. They’re installed standard on the Cirrus.
The next heaviest is on a Cessna 172, tested for 2550 pounds at 187 mph
Gosh, darn, folks beat me to this thread. Yes, we’ve had whole-plane parachutes for a couple decades now. Originally developed for ultralights, they have now been manufactured for up to four-seat airplanes.
It’s not just a matter of weight - the air force routinely airdrops much larger items weighing considerably more than a Cirrus SR22. It’s also a matter of speed. In the early phases of designed and using these 'chutes deployment sometimes resulted in things like the muffler or carbeurator falling off the aircraft, jarred lose by the opening of the 'chute and the shock of a sudden slow-down.
Although the 'chutes for Cirrus and Cessna 172’s are tested up to the 165 knot - 187 mph range, in a spin or a dive either of those planes can far exceed that speed - to deploy a 'chute at those speeds may not work. The chute may rip away, for instance. It’s been away since I saw the instructions for one of these, but they do mention things such as maximum deployment speeds and so forth.
From the article linked in the OP:
It was an explosion - the parachutes are deployed using a solid-fuel rocket that punches through the skin of the aircraft and gets the canopy outside in hurry.
At least 166 people - and Free Flight is not the only company to have made them.
I should also point out that, as wonderful as these 'chutes are, they are not to be used lightly, nor are they foolproof. There have been a significant number of people who pulled the Magic Red Handle and were either seriously injured or did not survive. Nonetheless, they can greatly increase the odds in one’s favor during a crisis.
There is also some risk to handling the systems, as detailed here. They were banned in the UK after three people were killed by them in ground accidents involving parked airplanes.
It would be great to have these on larger airplanes, but there the engineering problems are surprising complex. There was some discussion about this in a recent thread, as well as why you don’t see parachutes on commercial airliners: Parachutes In Commercial Airliners
None of this should be seen a discounting the value of a parachute when you need one - I just don’t like people to think they are instant and sure salvation in all situations.
The solid rocket boosters on the Space Shuttle have an empty weight of about 192,000 pounds apiece and they are returned to earth via parachutes.
A 747 weighs much more than that (I think the maximum takeoff weight is about 900,000 pounds these days) but it’s only a few times more.
You could probably build a parachute system that would bring a 747 down but it’d be tough to make it practical - keeping in mind that you don’t want the plane to break into a million pieces and that you have to do it softly enough into solid ground that the passengers aren’t killed. The weight of such a system would probably be prohibitive.
And finally you have to ask how many times a big passenger jet has been in a situation where such a recovery system would have saved it?
TWA 800 is the only instance I can think of involving an in-flight emergency where a parachute could have saved anyone - the nose of the airplane separated from the rest of it, and the rear portion remained intact and continued to climb up to 16,000 feet, then stalled and fell, still intact, into the sea. It is believe those in the fuselage probably retained conciousness until final impact. In that case, a plane-mounted parachute (assuming it would have deployed correctly), might have saved some lives. I don’t know if personal parachutes could have, there would have been the difficultly of getting out of the fuselage which was inclined at a fairly steep angle during most of the climb. Even under the best of circumstances, there was an extremely brief window of time in which 'chute could have been deployed - maybe a minute and a half.
That’s one instance in 100 years of flight. And that’s not even a certainty.
I am extremely doubtful that TWA 800 could have been saved. When they say the nose broke off they mean the entire fuselage forward of the wings. Any parachute system would need several dozen attachment points along the whole fuselage to distribute hoisting loads. Tearing the fuselage in half would have likely destroyed any parachute system. Never mind the fact that any control of a parachute system would have been lost when the plane was torn in half.
Now as farfetched as a ballistic parachute system might have been a workable one might have possibly been useful in a case like UAL 232 (The DC-10 that crash landed in Souix City Iowa) . They had no flight controls and managed to steer the plane somewhat with throttles.
I still have my doubts that a parachute system could be made big enough for a heavy that descent speed would be lower than that of a severe crash. Scaling is the problem. Little model airplanes can do things big ones can’t. When you scale something by a factor of 2 the area quadruples but the volume and mass go up by a factor of 8. Big airplanes can fly by virtue of the fact that the airspeed envelope from stall to max is in a much higher range than for small planes. The point of a parachute is for low speeds so it would require a vast area to be used on an airliner. The stored chute and deployment system would take up a significant amount of space and weight from the useable payload.
I’m extremely doubtful, too - even so, it’s the only crash I can think of off the top of my head where there is even a remote chance of usefulness.
I am not enough of an engineer to dispute this. However, one of the purposes of a parachute system in smaller planes is to increase the chances of survival in the event of an airframe failure - i.e. break up in flight. A lot does depend on how and where the 'chute is attached.
Even in small planes, you have absolutely NO control whatsoever over the parachute after you make the choice to deploy. There is no steering mechanism, none. You land where you land - and hope the spot is survivable. They aren’t always. A couple of fatalities have involved a successful 'chute deployment followed by death as a result of drowing (for water landings) or exposure or power lines or other ground hazards, like road traffic.
Good point.
Me, too - although the two recent Cirrus deployments resulted in no serious injuries (nor did the first one, if I recall correctly), over the 20-odd years these 'chutes have been in use broken bones and various other serious injuries have resulted from the landings. If we can’t garauntee a soft landing with a 1000 lb or 3000 lb aircraft there’s no way we could manage one for a big iron heavy.
There’s another issue - structural strength. A modern jetliner is really a tin can - it uses stressed skin construction to keep it together. For a parachute system to work, the plane would need a heavy ‘spine’ to keep it intact under the extreme shock. That is totally impractical. To say nothing of the extreme weight of the parachute system, the cost of redesigning the jets, and the lost cargo/passenger space to the very bulky parachute system.
And even if you could do all this, and you manage to get your plane floating down, you’d better hope you land in a Kansas wheat field or something. Because if this thing comes down on a mountain, or a town, or in the ocean, or on power lines, a lot of people are going to die anyway.
Remember, this thing would be deployed in some catastrophic emergency situation. No time to dump all the fuel. So, thousands of pounds of jet fuel are coming down with you.