Guns in planes myth BUSTED on nat'l TV!

[Brad Johnson]

Last night the "Mythbusters" guys settled the "guns cause planes to explode" myth once and for all, right there in front of the nations collective faces.

In case you missed it, they took an out-of-service airliner, pressurized the cabin, and proceeded to punch some 9mm holes in it to see if it would "exlosively decompress". Needless to say, it didn't.

First, they fired a round through the skin. Then, they fired a round directly through the center of a window. Neither hole produced anything more than a loud whistling sound as the air pressure equalized.

To get "explosive decompression", they had to bring in a pyrotechnician to attach a pretty hefty charge to the side of the plane. That finally did the trick, as the skin was peeled back quite impressively. Of course, those of you who know anything about explosives know that it was the massive overpressure of the actual blast, and not the measly 8psi of cabin pressure, that caused the final damage.

Myth BUSTED!! All the better that it happened right there on national TV. Now the whiney weasels that were using that particular myth as an excuse to keep air marshals off planes can just shut the heck up (oh, don't I wish).

Brad

 

[BowStreetRunner]

i watched a few minutes of that
pretty cool
i love the scene they showed from "US Marshals" where the gunhot pokes a hole in the airplane and the spacelike vacuum rips out people left and right
hahahaha
BSR

 

[Travis McGee]

It's true, but it won't matter, since the sheeple "learn" their "facts" from Hollywood.

 

[AZLibertarian]

I am a captain at a major national airline, so, naturally, I had an interest in watching last night's show. I was not at all surprised in the least in the results. As a matter of fact, Boeing testified before Congress after 9/11 that they were aware of at least 11 events where cabins had been punctured by bullets. While this information is in the public domain, the fact that most don't know about it is due to the fact that no explosive decompression occured.

Mrs. AZLib was not happy about the last part of the program where they rigged two explosive charges to get the results they were searching for with the bullet holes. She worried that they were showing the terrorists how to blow a hole in a plane. I told her that this is nothing new. Blowing a hole in the side of something is only a matter of getting the charge big enough (as the Mythbusters proved). You can blow a hole in a tank if you've got enough explosive.

 

[4v50 Gary]

Hollyweird taught the world in some James Bond flick that you get sucked out of airplanes and the world believes in Bond.

 

[Night20]

They still don't believe it...

http://discovery.infopop.net/1/OpenTopic?a=frm&s=6941912904&f=9401967776

 

[TonyB]

I love that show..sorry I missed this one...those guys are NUTS.....

 

[tetleyb]

Of course the best myth is getting shot with a handgun or a shotgun for that matter, and flying across the room...

 

[boofus]

What about all the cars in Hollyweird movies that are all loaded with dynamite? You can run a Hollywood car into a mail box and the whole thing would blow up. Guess that's why 1 or 2 gun shots always turns them into torches.

 

[cookhj]

ok, well if people still don't believe the mythbuster, why don't adam and whoever go up in a plane and shoot a few holes in it to show people that a plane won't rapidly decompress.

 

[TarpleyG]

Was the plane airborne when all this business was taking place? Just wondering if that might skew the results any.

GT

 

[Kestryll]

World War 2 fighters used to fly at around 375 to 400 MPH, faster in dives.
Those were non-pressurized cockpits that certianly were not air tight. I dodn't seem to recall pilots being sucked out by the vacuum, not even in dives when they approached 0g.

 

[AJ Dual]

I (heart) Mythbusters

Pressure differental is all that matters, as long as you over pressure the plane enough on the ground vs. the outside atmosphere, it's the same as in flight, and it looks like they pressurized the plane higher than a normal flight diference anyway.

They pumped the cabin of the plane to about 8 psi greater than the outside air, which is more than the difference at flight altitudes I'll bet. Usually commerical jets are pressurized to 10 psi +/- (5000 feet about? AZLib help me out here...) and the outside air is about 4-5 psi at cruising altitude (35,000 feet?), as opposed to a standard 14 psi at sea level.

A bullet makes a whistling hole you could safely put your hand over (You might get a hickey and a frostbit spot on the hand, but that would be it.) A strong man ought to almost be able to momentarily suck or blow 5-8 psi through a 9mm hole IMO.

Larger structural failures and bombs like they tested at the end take out big chunks, not because of decompression, but because large pieces of the airframe are suddenly jutted out into the 500 mph slipstream outside the plane and they get torn off. Like the roof of that Air Aloha plane in the 80's that was so famous.

It's amazing to watch those people on the Discovery Channel board keep wrangling solutions about altitude and airspeed as to why it might still happen.

 

[Blackcloud6]

I had to go through "Chamber Training" when I was assigned as the Army Ground Liaison Officer to the Fighter Wing at Selfridge ANGB. My duties required periodic flights in the two-seat F-16D (he plane I nicknamed the 'Barf Mobile' but that's another story)

In order to fly at the altitudes we did and use the oxygen equipment I had to go through the training. I did it at Wright-Patterson AFB in Dayton, OH. They have a chamber that takes you "up" to different altitudes and they take you through different situations, slow-decompression (the most dangerous by the way as you start suffering Hypoxia and don't know it) and rapid-decompression. In the rapid one, there was a loud bang and a sudden fog, but nobody got sucked through the opening. It is dramatic but not like what TV would show you. Also, I think the bullet scenario would cause a slow decompression, not a rapid one.

The slow decompression was really strange as they had us do puzzles on a puzzle board and our oxygen masks off. As you sufferred from oxygen deprivation, it became harder and harder to do even the simple things, like basic math and spelling games. Then at some point they told us to put on the mask and suddenly it was like someone turned on the lights and I noticed the puzzle board was larger with dials and instruments on the outside edge that I never had seen while my mask was off. This was kind of scary because I never really knew what was happening to me. This is probably what happened to the golfer and his jet crew years ago when they flew across the nation dead in their seats. In our class, nobody got sucked out of the chamber during slow decompression, we never even knew it was happening.

 

[labgrade]

We did some very significant failure analysis on our disc drives used in commercial avaition. "Commercial standards" we were given suggested that an airliner is pressurized to "~8500K' +/-" I don't know what the "+/-" is, but would suspect that the minus side would hold sway, all told.

Still, after 9/11, in the TFL conversations about handguns in cockpits, it was amazing who many of "our own" still "felt unconfortable" about it all. & this after discussion from pilots, A/C design engineers - you know! people who actually know! rather than "feel."

Can't wait for the MythBusters to do one on "The BIC lighter is equal to 7 sticks of dynamite" nonsense.

 

[Nestor]

My Reply.

Hi, new to this board but have debated this many times. So here is a new bone to chew on for you in the pro "Hollywood" decompression camp.

The B-29 SuperFortress was fully pressurized when at altitude as are all Modern US Jet Transports & Bombers (C-141 Starlifter C-5A Galaxy C-17 Globe Master III B-52 StratoFortress B-1b Lancer B-2 Spirit )If expolsive decompression is true as seen on the silver screen then no B-29 ever had battle damage with out loss of the aircraft and The USAF is willing to write of multimillion dollar aircraft to a fragment from a SAM or cannon fire. Worse yet multiple nuclear weapons would fall from the sky if at any time since the introduction of the B-36 Peacemaker one of our bombers while on a deterrent flight had a cockpit window fail.

 

[Bill Hook]

Mrs. AZLib was not happy about the last part of the program where they rigged two explosive charges to get the results they were searching for with the bullet holes. She worried that they were showing the terrorists how to blow a hole in a plane.

I think the Libyan security services are waaaay ahead of Mrs. AZLib about the potential of explosive charges, explosive decompression and jumbo jets.

 

[AZLibertarian]

AJ

Usually commerical jets are pressurized to 10 psi +/- (5000 feet about? AZLib help me out here...) and the outside air is about 4-5 psi at cruising altitude (35,000 feet?), as opposed to a standard 14 psi at sea level.

While I won't speak for every aircraft pressurization system, the one I fly now (MD80 series) usually pressurizes to 7-8psid (pounds per square inch differential). I also flew the Boeing 757 and 767 airplanes, and while I don't exactly remember their numbers, I believe they pressurize at about the same range. This usually equates to a cabin altitude of no more than 8500'. You're right that pressure differential is all that matters here. It doesn't matter if you get your 8psid while at 35000' above sea level, or while in a pressurized "wreck" in the boneyard, as the Mythbusters demonstrated.

Blackcloud's stuff on pressure chambers is exactly right. An explosive decompression is a bad thing, but slow decompressions are worse. Hypoxia is a slow killer, and the symptoms are subtle, but it is a killer none-the-less.

My guess is that, were I flying the plane while the Mythbusters shot a hole into a window, that the only way I'd know that we had a new hole in the plane would be the commotion from the passengers and crew about a gunshot. Its only a guess, but I don't think it would amount to any measureable stress on the pressurization system.

 

[Fly320s]

Modern commercial aircraft are built to withstand a certain pressurization differential.

For instance, the Airbus 320 has a maximum of 8.1psid. If we have the airplane at maximum pressurization differential while flying at 39,000 feet, our max altitude, then we get a cabin altitude of roughly 8,000 feet.

The manufacturers look for a balance between:
1. How high they want the aircraft to be able to fly (max alt.)
2. How fast the a/c can descend in the event of depressurization
3. How high the cabin altitude can legally and comfortably be
4. How much all this structure to withstand the pressure must weigh
5. And of course, how much will this cost.

Plus a long list of other items that I don't know about.

 

[dav]

AZLibertarian wrote (in part):
... I'd know that we had a new hole ...

(emphasis mine)
I like to sit in the emergency exit rows. The door almost always whistles.

As mentioned above, a bullet would put a new hole in an airplane. They already have holes in them.

 

[twoblink]

I recall reading an emergancy instruction manual that said "in case of hole in cabin, place WET CLOTH NAPKIN OVER THE HOLE"..

So not a big deal if it's a 9mm hole...

 

[M67]

Blackcloud6

As you I suffering from oxygen deprivation

Did you type that sitting on an adjustable desk chair? If so, maybe you should take it down to a safer altitude?

Seriously, at what (simulated) altitude did hypoxia occur? I've experinced something like it once but I knew what was happening, and that was kind of a weird feeling. I was walking down from 19,000 something feet when my mind started to work at two different levels, one part of my brain knowing exactly what was happening to me, while the other part couldn't care less.

 

[45R]

That show is the best. If it comes on help me...I am glued to the TV for an hour!!!

 

[michiganfan]

AZ are you the pilot in the picture going around the net showing the airline pilot leaving his home carrying the 50 caliber rifle

 

[Autolite]

pressure differential, not speed or altitude...

Just to underscore what has already been pointed out. We used to do air pressurization checks on C130s on the ground. A safety valve, about the size of a human fist would pop open at max differential cabin pressure. Nothing remarkable happens. We would also pop open the emergency cabin depressurization valve at 1 or 2 psid. That valve is the size of a garbage can lid and all you would get is a slight 'pop' in your ears. The bullet hole thing is most definately a myth ...