IT WORKS New [aircraft] parachute saves four lives

[Ivan Seeking]

KELOWNA -- A high-tech parachute unfurled from a special gap in the fuselage of small plane hurtling to the ground this week, carrying the aircraft down safely and saving the lives of four Alberta residents...

...The plane, a Cirrus aircraft, started spiralling out of control after taking off from a refuelling stop in Kelowna Thursday night.[continued]

http://www.theglobeandmail.com/servlet/ArticleNews/TPStory/LAC/20040410/PLANE10/TPNational/Canada

The pilot of a small disabled, single-engine airplane, which floated to a safe landing instead of crashing, can thank NASA and a Minnesota company. The pilot walked away, from what would have been a catastrophic crash, with just a stiff neck...[continued]

http://spaceflightnow.com/news/n0211/22parachute/

The technology to apply this to commercial aircraft already exists though the Apollo program. Aviation will never be the same.

Edit: boy my spelling really sucks when I haven't slept for a day and a night. :yuck:

 

[Gokul43201]

Right, the airline industry is just waiting to spend millions of dollars on extra safety measures.

Anyway, it was cool to read this as I had previously (a month ago ?) come up with an idea like this (using parachutes) in response to a post by someone who was suggesting firing off a tethered rocket. At the time, I had no idea that it was actually being implemented.

 

[russ_watters]

The technology to apply this to commercial aircraft already exists though the Apollo program.

Right, the airline industry is just waiting to spend millions of dollars on extra safety measures.

Its really only for private planes. First, they are small, second they fly lower (and hence can't glide as far) and third, they are much more dangerous than airliners.

I can think of only two incidents in recent memory where this type of system might have made a difference: the last airliner crash (Nov 2001) in the US was an airbus that had its tail rip off causing it to frisbee in. About 10 years ago, an Alaska-air MD-80 or similar plane had a control malfunction in the tail.

There are so few airliner crashes that this may be useful for that it doesn't seem worth it for me.

 

[aychamo]

Err, I'm sure you would have the same opinion if your loved one died on the plane that could have had the parachute, but it just wasn't "worth-it."

 

[Ivan Seeking]

First, not to create any confusion, these are only in use with small aircraft. The system used for re-entry by the Apollo progam can allegedly be modified to work for a commercial aircraft but the economic and engineering problems are obvious. Still, the initial objections [not made here] that such a system couldn't be made are already addressed. It seems that this can be done. I haven't even had time to look at the statistics but here is a link for an air crash database.

http://www.crashdatabase.com/

 

[Ivan Seeking]

There are so few airliner crashes that this may be useful for that it doesn't seem worth it for me.

What about the planes from 911? This would provide an option of last resort should control of the plane be seriously threatened. This does imply a hefty benefit to cost ratio.

 

[russ_watters]

Err, I'm sure you would have the same opinion if your loved one died on the plane that could have had the parachute, but it just wasn't "worth-it."

Well, I don't know - with the money spent on parachutes in a thousand planes, how many more cars could have airbags? Or if you're really into airline safety, how about collision avoidence (ground and in the air) or wind-shear detection. Or we could upgrade our air traffic control computers (the only computers in the country that still need vacuum tubes). Deciding what to spend money on is about weighing risks: the risk of dying in an airliner crash isn't even in the top 100 of the most likely ways you'll die, somewhat below the risk of being killed by lightning. Its not worth worrying about. The only reason people do worry about it but don't worry about dying in a car crash (depending on your age, its in the top 5 of most likely ways you'll die) is because plane crashes, as rare as they are, are more spectacular.

http://www.ntsb.gov/aviation/aviation.htm
http://www.ntsb.gov/aviation/Table6.htm
Looks like I was wrong though - there were 2 accidents with fatalities in 2003 in the US. One was a commuter plane that killed 21 people (was that the one that nosed-up on takeoff and stalled?). The other was a ground crew member who got run over. Thats odds of 1 in roughly 5 million for any particular flight that you would have been involved in a fatal accident, about average for the past decade.

What about the planes from 911?

I'm not sure what you mean - could the pilot or co-pilot have punched the chute after having their throats cut? Remote control from the ground (though we didn't know anything until the first plane hit)? A flight-attendant? I can't picture a scenario where a parachute would have made a difference.

It may be reasonable to put them on commuter planes or require them for general aviation - the planes are smaller so it costs less per plane and far more fatalities could be prevented.

 

[Ivan Seeking]

I'm not sure what you mean - could the pilot or co-pilot have punched the chute after having their throats cut? Remote control from the ground (though we didn't know anything until the first plane hit)? A flight-attendant? I can't picture a scenario where a parachute would have made a difference.

Like I said, as soon as control of the plane is seriously threatened - such as just as the hijacker’s crash through the cabin door.

What strikes me is not how many crashes occur but the money spent for security and safety. Given a failsafe system of some sort, then it seems that the use of aircraft as weapons is made virtually impossible.

Can anyone guess at the cost of such a system? Maybe that number alone would end the discussion. Is possible that this would not be incredibly expensive? For the sake of discussion, what is the cut off price- where this is not worth doing: $10,000, $100,000, $1,000,000 per plane?

 

[russ_watters]

Like I said, as soon as control of the plane is seriously threatened - such as just as the hijacker’s crash through the cabin door.

Well - its one thing for a cessna to float to the ground under a chute, but a whole 'nother for a 757 - there's still a decent chance everyone on the plane will die. Come down in a soft field and you're probably OK. Come down in Queens or a forrest and there'll be problems.

 

[Ivan Seeking]

Well - its one thing for a cessna to float to the ground under a chute, but a whole 'nother for a 757 - there's still a decent chance everyone on the plane will die. Come down in a soft field and you're probably OK. Come down in Queens or a forrest and there'll be problems.

Though death did not strike me necessarily as a consequence, it would make for some strange and difficult situations, at least.

What do you think of the cost issue? I know this would seem to be a very expensive proposition, but then it strikes me also that this may not be so bad as one might think.

What is the cost of a 7E7 these days? Boeing just sold about 50 to JAL I think…I know they just made a big sale.

Side note: When I was a very young child a Goodyear blimp crashed very near our house. I can still vaguely remember that blimp hanging from the power lines over the Blvd in Paramount…or thereabout. It was quite a sight to behold. Imagine a 777 floating down and landing on your house.

 

[russ_watters]

What is the cost of a 7E7 these days? Boeing just sold about 50 to JAL I think…I know they just made a big sale.

Dunno about a 7E7, but according to Google, a 777 will run you about a billion and a half. So even if it costs a couple of million dollars, it wouldn't be a large fraction of the price.

 

[Zorodius]

Like I said, as soon as control of the plane is seriously threatened - such as just as the hijacker’s crash through the cabin door.

Wouldn't it make more sense to have a button that instantly locks out the pilot's control of the plane and transfers it to the air traffic controllers? Dropping a commercial airliner onto a populated area would be a bad thing even if it was slowed by a parachute, and the hijackers would still have some success, even if they were not able to fly the plane into their target of choice.

 

[Cap'n Refsmmat]

Exactly. The hijackers would just wait until you are over the target city, and then attempt to hijack the plane. The parachute foils their attempt, but the plane still crashes into a populated city, killing many.

 

[Ivan Seeking]

Wouldn't it make more sense to have a button that instantly locks out the pilot's control of the plane and transfers it to the air traffic controllers? Dropping a commercial airliner onto a populated area would be a bad thing even if it was slowed by a parachute, and the hijackers would still have some success, even if they were not able to fly the plane into their target of choice.

Good point but I don't know if in practice this could be done or not. Someday, sure, but not any time soon I would think. I know that the autopilot usually lands the plane so onboard computer control is definitely possible, but I doubt it would be so easy to hand off control to another location. Also, all that need be done is to damage the controls. I am quite sure that in a pinch, if I were a hijacker, I could take out the autopilot with little panel damage.

Another thought, is it likely that a chute system would fail - resulting in the uninteneded deployments of the chute under otherwise safe conditions - more frequently than it is likely to be of aid. In other words, what is the likelyhood that it would cause more problems than it would solve?

 

[Cap'n Refsmmat]

I know that the autopilot usually lands the plane

Only in 0 visibility. Pilots don't really trust the autopilot, all it does in landing is present ILS information, like where the runway is and at what angle, altitude, and that.

 

[hitssquad]

Well - its one thing for a cessna to float to the ground under a chute, but a whole 'nother for a 757

Why would that be?

 

[russ_watters]

Why would that be?

We kinda already covered this. A 757 floating to the ground under a chute at the same speed that a cessna can touch-down safely will crush itself and anything under it on impact.

 

[Ivan Seeking]

Only in 0 visibility. Pilots don't really trust the autopilot, all it does in landing is present ILS information, like where the runway is and at what angle, altitude, and that.

This directly contradicts what I have been told recently by pilots. For example, a few weeks ago I was landing in Dallas. On final approach the plane made an unusual manuever and accelerated strongly for a few moments followed by a return to the glide path. After landing I asked the pilots what had happened. They shrugged and said that the autopilot didn't like something about the approach. This was on an American Super 80.

 

[Ivan Seeking]

We kinda already covered this. A 757 floating to the ground under a chute at the same speed that a cessna can touch-down safely will crush itself and anything under it on impact.

Are we sure this is true? I will check the weight to area ratio later, say for a 767, if no one else knows this.

 

[russ_watters]

This directly contradicts what I have been told recently by pilots.

You guys are talking about two different things. ILS is just presenting information - good information - to the pilot so the pilot can fly the plane. It on its own isn't part of the plane's autopilot. ALS (I think) is the automated landing system that can actually fly the plane to touchdown using the plane's autopilot when linked to some sort of ground-based information system (possibly coupled with ILS). I'm a little thin on facts here too, but I was under the impression that about half the time, the autopilot flies the plane to touchdown.

Any pilots around with more info...?

Are we sure this is true? I will check the weight to area ratio later, say for a 767, if no one else knows this.

Its all about scale. You could drop a model plane off a building and if it lands on its feet it won't be damaged. Its the same reason (from another thread) that a balsa-wood bridge of 1' span will hold 100x its own weight and a steel bridge of 1 mile span can't even support itself.

Structural loadings scale faster than structural strength.

edit: http://www.public-action.com/911/facsnet/aviation.php3 is an article that gets right to the heart of the autolanding vs terrorism issue:

Autoland systems have been in wide commercial use in different parts of the world since the 1980s. Auto landings are routinely performed thousands of times a day throughout the world...

1. The "CAT IIIa" approach is flown by an aircraft equipped with three separate autopilot systems (one for actually commanding the aircraft, and two for backup) to a decision altitude of 50 feet...

2. CAT IIIb is a true autoland category, that is, the approach and landing touchdown are controlled entirely by what is known as a Flight Management System, or FMS...

3. A CAT IIIc autoland approach has a higher alert height, 100 feet, then a IIIb landing, but a shorter RVR of 300 feet...

In all three categories of approach, the Flight Management System is entirely capable of landing the aircraft and, in some CAT IIIc-equipped aircraft such as the Boeing 747-400, capable of applying the brakes after touchdown and stopping the aircraft as well...

I'm curious about stats though...

 

[Ivan Seeking]

Structural loadings scale faster than structural strength.

Its not possible to design the chute system to land the plane in a good position? Or do you mean that anything under the plane, like a house, would unavoidably collapse the structure of the craft on landing?

 

[russ_watters]

Its not possible to design the chute system to land the plane in a good position? Or do you mean that anything under the plane, like a house, would unavoidably collapse the structure of the craft on landing?

I'm talking about the aircraft structure and anything under it withstanding the deceleration of touchdown. But there is also the issue of the airplane crushing whatever is under it. Slowly lower a cessna onto the pitched roof of a house (or small office building) and the house would probably support it. Slowly lower a 757 onto the roof of the same house and...

 

[Ivan Seeking]

Yes, landing on a house would be bad.

Still, if this was the last alternative to either losing control of the aircraft to terrorists or plunging to Earth at 600 mph, it may be preferable. Do you remember the jet that crashed in Cerritos Ca, many years ago [very near my house at the time]? Talk about an ugly scene - they were finding body parts in the bushes for weeks.

You just don't see this as a best option in a worst case scenario? This is still hard for me to get past. If it is only used in the case near certain disaster...

 

[russ_watters]

You just don't see this as a best option in a worst case scenario? This is still hard for me to get past. If it is only used in the case near certain disaster...

Yes, in some cases it may be better than nothing. The problem as I see it is in the decision-making process. Who makes the decision, when, and based on what?

 

[Cliff_J]

I think the implementation challenge isn't one to overlook as well. Beyond calculating if a 30 year old airframe can withstand the loads, multi-stage parachutes to slow 100+ tons at 500MPH would be no trivial matter. Then planes like a 737 or DC10 with a tail mounted motor...et cetera.

I'm no NTSB expert by any means but the shows on TV I've seen about crashes show a large number of them happening on approach/departure and not at full altitude where a parachute's effectiveness would be meaningful.

And as Russ asked, who makes the decision. Isn't the percentage of crashes attributed to pilot error something like 70% or more?

Cliff

 

[russ_watters]

Its a complicated question in a number of ways. It may be instructive to examine a handful of crashes and see if we can determine what the best course of action would have been (in hindsight) and then evaluate the possibility that someone (pilot, stewardess, ATC, computer?) could have made the same decision. The NTSB pages I linked have pretty much all the relevant info. Here are the last 10 crashes by US carriers:

08/02/97 LIMA, PERU CONTINENTAL AIRLINES BOEING 757-200 1 141
12/28/97 PACIFIC OCEAN UNITED AIRLINES BOEING 747 1 373
06/01/99 LITTLE ROCK, AR AMERICAN AIRLINES MCDONNELL DOUGLAS MD-80 10 129
01/31/00 POINT MUGU, CA ALASKA AIRLINES MCDONNELL DOUGLAS MD-83 83 0
09/11/01 NEW YORK CITY, NY AMERICAN AIRLINES BOEING 767-200 81 0

09/11/01 NEW YORK CITY, NY UNITED AIRLINES BOEING 767-200 56 0
09/11/01 ARLINGTON, VA AMERICAN AIRLINES BOEING 757-200 58 0
09/11/01 SHANKSVILLE, PA UNITED AIRLINES BOEING 757 37 0
11/12/01 BELLE HARBOR, NY AMERICAN AIRLINES AIRBUS INDUSTRIE A300-600 251 0
01/08/03 CHARLOTTE, NC US AIRWAYS EXPRESS Beech 1900 19 0

The most recent was a commuter that IIRC crashed on takeoff. It was overloaded/out of balance, pitched up on takeoff, stalled, and crashed. Like Cliff_J said, in a case like that, a parachute is unlikely to inflate.

Next was the Airbus who'se vertical stabilizer snapped and frisbee'd in. That's probaby a good candidate when viewed in hindsight. It wasn't real high (a couple of thousdand feet?) but may have been high enough and slow enough for the chute to deploy. Landing in a city, you still might kill everyone on the plane (one severed engine can turn it into a fireball), but at least they would have a chance.

Now the tough part though: could the decision have been made? The pilots didn't know they didn't have a vertical sabilizer and at the time it snapped were already in an iffy place control-wise (wake turbulence). Would they have realized their situation was hopeless with enough altitue and attitude to pop the chute? I tend to doubt it.

Next 4 are 9/11. Clearly, in all 4 cases a parachute would have been preferable. But who makes the call and when? I highly doubt anyone knew what was coming before the 1st plane hit the WTC. At the time the 2nd plane hit the WTC, who knew it was hijacked? IMO, the decision cannot ever be made by flight attendant, computer, or ATC. Its too big. That leaves FAA and upper-level government officials. None could have made that decision - I'm pretty sure they didn't know. I'm not sure about the Pentagon plane, but the 3rd was positively ID'd as hijacked and an intercept was underway when it went down. It was in as good a place as any for a ditch. It would have been a good decision and Bush himself was in a position to make the call. Still, not knowing about the uprising, would a decision have been made in time? Questionable.

A quick word on pilots and decision-making. Most are ex-military and as such they are decisive but tenacious. They would be unwilling to give up on a plane while they still have altitude. That's fine for a fighter with an ejection seat that works while sitting on the ground, but for a jetliner needing 1000 (2000?) feet for a parachute to open, that's a big decision with questionable information.

 

[Cliff_J]

Well stated. From what I've seen, the ejection seats work even if the plane is on the ground, much smaller loads to consider when its only a pilot and seat plus the rockets are likely designed to both clear the tail section at speed and provide the altitude needed for a ground ejection.

From what I know about impacts from some car crash shows, a change in speed (heard it called delta V) exceeding 20MPH can cause lethal injuries. No clear timeframe for such accelleration was stated and obviously many more factors are involved to determine survivability, but regardless we are fragile masses of tissue when an impact is concerned.

Given that the plane would likely still be traveling to the ground at 60MPH+ and if in a nose down/tail up position like the Cessna parachutes, its pretty obvious that the pilots and first class passengers have the most to lose as being seated in the effective 'crush structure' for a huge amount of mass. That would require some very difficult decisions for the flight crew.

As far as the 9/11 planes, one would have had to hope that the chutes were designed to be deployed at max speed full fuel load and full throttle conditions. I'm just trying to visualize what size steel cables the chute would need...scary. Hopefully we're never in that position again, the lessons of the past should have taught us well by now.

Cliff