Why aren't planes equipped with huge parachutes?

Ultralight planes often ARE equipped with a ballistic parachute. Pull the pin, press the red ohshit button and a parachute is launched by a small rocket charge. I crashed an ultralight once, too low to use the ballistic chute when the problem developed. Bigger planes are too heavy. The chute would have to be enormous.

sc42 wrote:

Ultralight planes often ARE equipped with a ballistic parachute. Pull the pin, press the red ohshit button and a parachute is launched by a small rocket charge. I crashed an ultralight once, too low to use the ballistic chute when the problem developed. Bigger planes are too heavy. The chute would have to be enormous.

^exactly. Parachutes are large and heavy. In addition, parachutes may prevent fatalities (although it may not) but it will not save the airframe. Preventing fatalities is a worthy goal, but often other systems (backup systems, more fuel, etc) may increase safety a lot more than the parachute for many planes.

I first saw these back about 1993, Not only for ultralights but light aircraft as well. Above are 2 sources

Not what you were after but many military aircraft are equipped with drag chutes that is used to slow after touchdown Even planes as bigg as the BUFF and as fast as F16s

With all the letsrun mathematicians here recently commenting on the deflategate temperature facts about pressure.... I'd hope at least 1 or two of them pop in here and figure out just how big of a parachute would be needed for a standard 747. It probably would need to be impractically large, but I'd be curious as to just how large.

chutes and ladders wrote:

http://www.madsci.org/posts/archives/2010-07/1279028465.Ph.r.html

That's way to much math for me. Anyone want to take a stab at it? Secondary question would be what would be the weight of that huge parachute?

What they could do is build big trampolines every ten miles or so, so if a plane starts to crash it can just head for the nearest trampoline and bounce back up.

How often would such a thing really help? If a plane breaks up in the air, a parachute obviously wouldn't help. Similarly, if the failure occurs very close to the ground, there wouldn't be time to effectively deploy a chute.

So how many accidents occur where the plane is high enough for the chute to work, and the plane's body doesn't break? Seems like the chute would only help in a very small minority of cases, since most accidents occur on takeoff or landing.

It makes more sense to simply install an insta-inflatable dirigible in all airplane. This way the plane will float gently down to the ground, and the dirigible can be directed to an airport for a safe landing.

ekw wrote:

chutes and ladders wrote:http://www.madsci.org/posts/archives/2010-07/1279028465.Ph.r.html

That's way to much math for me. Anyone want to take a stab at it? Secondary question would be what would be the weight of that huge parachute?

quickly, I found the radius of the parachute to be around 460ft, to give a velocity of 35mph.

Dirigible wrote:

It makes more sense to simply install an insta-inflatable dirigible in all airplane. This way the plane will float gently down to the ground, and the dirigible can be directed to an airport for a safe landing.

even cheaper would be to have a calculation of when it's going to hit the ground that gives a countdown screen in the cabin. Then everyone could jump right before it hits so they'd be fine

Bad Wigins wrote:

What they could do is build big trampolines every ten miles or so, so if a plane starts to crash it can just head for the nearest trampoline and bounce back up.

I like this answer ^

The added weight would make it much more fuel inefficient for a 747 to take off from a treadmill.

would it really help? wrote:

So how many accidents occur where the plane is high enough for the chute to work, and the plane's body doesn't break? Seems like the chute would only help in a very small minority of cases, since most accidents occur on takeoff or landing.

I have no statistics, but my experience says you are onto something here. Takeoff and climbout is a significant time for airplane accidents. For small aircraft, ultralights, trikes, etc. they use a ballistic parachute system which deploys very rapidly. That sort of system really doesn't scale so it is not very practical in larger planes.

Weight, though, is really the larger picture. A parachute large enough to lower a plane of any size is going to be really large. That will reduce the amount of fuel the plane can carry. Fuel starvation is one of the leading causes of airplane accidents (though not in commercial passenger flights). And storage--in addition to the weight there needs to be a place to store the parachute--the wings being the mostly likely place but that is often where the fuel is stored.

I believe the largest plane w/ a parachute recovery system is the Cirrus, which seats either 4 or 5. I think it is possible for a system to work in a slightly larger airplane but certainly not in mos commercial airliners.

But generally you are talking about a system which is going to be deployed very, very little which is going to cost a lot to design and test--and then cost a lot to fly with it because of the extra weight. Other systems and improvements can likely add more to safety at less cost.

aerofoil wrote:

Not what you were after but many military aircraft are equipped with drag chutes that is used to slow after touchdown Even planes as bigg as the BUFF and as fast as F16s

Drag chutes are an entirely different proposition

Hingle McCringleberry wrote:

Why aren't planes equipped with huge parachutes

Because commercial aircraft are not designed by morons.

Seems logical to me

That's why you are not an aircraft designer.

A better question would be: why aren't planes equipped with giant treadmills so they can always stay in the air?

This is my summize.

A main parachute and harness weighs 20-25% of an average adult's bodyweight, so a parachute for a 777 would have to weigh about 130,000lb reducing maximum capacity by over 40%. In additon

- Stabilizers would be installed to prevent rolling further increasing weight.

- The parachute would have to be fireproofed to preventing the engines from setting it on fire..

- The parachute would have to be placed centrally, increasing drag. If you placed it at the front or rear, the plane could not fly or land horizontally.

- The demand for raw materials would increase it's price signifcantly, as would the additional labor costs..

I read this thread and my initial thought was parachutes for every passenger, not the entire plane itself (thats retarded). Just a parachute stuffed under every seat or in the overhead, and when the planes engines fail or someting happens in the air, everyone grabs their chute and are ushered out the side of the plane to safely deploy their parachute and not die in a tragic firey accident. Remember when that pilot had to land his plane full of passengers in the Hudson? that was bad@ss, but how much more convenient would it have been if everyone just parachuted out of their and just let the plane crash into some uninhabited area? Idk, just a thought.