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Old 07-13-2018, 04:36 AM
EricaRoche EricaRoche is offline
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What damage could someone with a loaded gun do to an airliner itself?

Hypothetical of course...I remember reading a story of a scandal involving TSA/CBP agents that allowed guns to board a plane in some US city.

Assuming that those passengers with the handguns intended to use them for maximum damage besides murder, could shooting the windows depressurize the plane? I imagine they wouldn't be able to get through the cockpit as its made of bulletproof Kevlar.
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Old 07-13-2018, 04:48 AM
Richard Pearse Richard Pearse is offline
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A few bullet holes would be unlikely to depressurise the plane, there are already several large holes in the fuselage that have controllable valves to let an appropriate amount of air out so it doesn't over-pressurise. Even if it did depressurise, it's not a big issue, the plane would be flown to a lower altitude and the passengers provided with O2 for the interim.
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Old 07-13-2018, 06:27 AM
BobBitchin' BobBitchin' is online now
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Could a .357/.44 mag get to avionics?

Shoot through the fuselage, into the wing, blow out some hydraulics, take out a fuel tank?


Or you could use the gun to steal cheap beer, pickled eggs and taco bell.

I could fuck up an entire stadium after two days on that diet.
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Old 07-13-2018, 06:39 AM
Joey P Joey P is offline
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Quote:
Originally Posted by BobBitchin' View Post
Could a .357/.44 mag get to avionics?

Shoot through the fuselage, into the wing, blow out some hydraulics, take out a fuel tank?


Or you could use the gun to steal cheap beer, pickled eggs and taco bell.

I could fuck up an entire stadium after two days on that diet.
I believe I've seen documentaries that have mentioned that all the flight control surfaces have redundant systems from beginning to end, specifically so something like a blown hydraulic line doesn't take the plane down. I'd also be surprised if a bullet sized hole in a fuel tank would cause a leak big enough to even be noticeable. A large passenger plane is going to have something like 30,000 gallons of gas. At about a gallon per second, the engines will use it faster than it would drain.

The OP didn't want to count murder, so lets say 'disabling' the pilots would probably do the most damage.

Maybe shooting the engines and hoping the bullets ricochet around just right to cause some of the blades to break off and jam everything up.

ETA, even if you could manage to hit the fuel tank, I'd be even more surprised if after going through the fuselage, top of the fuel tank and the fuel itself if it had anywhere near enough momentum to make an exit hole out the bottom of the tank in order to actually cause a leak.

Last edited by Joey P; 07-13-2018 at 06:44 AM.
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Old 07-13-2018, 08:45 AM
Machine Elf Machine Elf is offline
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Originally Posted by Joey P View Post
I believe I've seen documentaries that have mentioned that all the flight control surfaces have redundant systems from beginning to end, specifically so something like a blown hydraulic line doesn't take the plane down.
This. United 232 was a one-in-a-million incident in which an uncontained engine failure happened to send large pieces of debris crashing through the one area on the plane where all three hydraulic systems passed by in close proximity to each other, disabling all of the flight control surfaces. If you're shooting a handgun from inside the fuselage, you'd need to fire three extremely lucky shots to achieve the same result.

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Originally Posted by Joey P View Post
I'd also be surprised if a bullet sized hole in a fuel tank would cause a leak big enough to even be noticeable. A large passenger plane is going to have something like 30,000 gallons of gas. At about a gallon per second, the engines will use it faster than it would drain.
If you've got a powerful gun and good aim, you might be able to shoot a hole in one of the wing tanks; that would require penetrating the fuselage and the wing skin. But you'd probably only penetrate the top of the tank; if there's a meaningful amount of fuel in the tank, it will slow the bullet down rapidly, which means you're unlikely to pierce the bottom or side of the tank. Even if you did, the pilots are able to pump fuel from one tank to another, so if a leak is observed, they'll transfer fuel out of the leaky tank to avoid losing it.

You could cause a decompression event by putting a hole in the fuselage, but it wouldn't be a very big hole. Bleed air from the compressor section of the engine(s) is what they use to maintain cabin pressure during cruise. It'll take a pro pilot to answer with more certainty, but I'll wager there's more than enough bleed air to compensate for whatever leakage is being caused by one bullet hole. And even if not, it'll at least partially compensate for it, resulting in a very slow rate of cabin pressure loss. And even if there were zero bleed air available, one little bullet hole is pretty small compared to the total amount of air that's impounded inside the fuselage; cabin pressure will drop at a relatively slow rate, giving you plenty of time to put on your O2 mask, and giving the pilots plenty of time to descend to a safe altitude.

Last edited by Machine Elf; 07-13-2018 at 08:47 AM.
  #6  
Old 07-13-2018, 09:14 AM
Elendil's Heir Elendil's Heir is offline
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Need answer fast?

In any event, no one would painfully be sucked outside through a tiny bullet hole. That's pure Hollywood.
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Old 07-13-2018, 09:26 AM
MichaelEmouse MichaelEmouse is online now
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Do we presume they can't get into the cockpit at all? If you act with enough stealth and intel, you could get into the cockpit by knocking.

If they can, shooting the cockpit controls could make it impossible to fly the plane. Shooting the cockpit window could also make piloting a challenge.

If not, the only thing I can think of is shooting the engines. Probably wouldn't work on a tri-engine plane.

On second thought, if you knew enough about the plane's blueprints, you might be able to shoot the communications cables from the cockpit to the rest of the plane. It would do the equivalent of severing the spinal cord.

Last edited by MichaelEmouse; 07-13-2018 at 09:27 AM.
  #8  
Old 07-13-2018, 10:07 AM
Joey P Joey P is offline
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Quote:
Originally Posted by Machine Elf View Post
This. United 232 was a one-in-a-million incident in which an uncontained engine failure happened to send large pieces of debris crashing through the one area on the plane where all three hydraulic systems passed by in close proximity to each other, disabling all of the flight control surfaces.
It's entirely possible that's what the documentary was about when I learned about the redundant systems.


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Originally Posted by MichaelEmouse View Post
Do we presume they can't get into the cockpit at all? If you act with enough stealth and intel, you could get into the cockpit by knocking.

If they can, shooting the cockpit controls could make it impossible to fly the plane. Shooting the cockpit window could also make piloting a challenge.
On at least one airline, off the top of my head, that wouldn't work. El Al, has a steel cockpit door with a code required to open it. Once you pass through that door and close it behind you, then then after the pilot identifies you, a second door opens to the actual cockpit. I'm not sure if that's so a 'bad guy' would be trapped in that area for the duration of the flight or if it's to make it difficult to get more than one person (hostage, second 'bad guy') through at a time.

The first time I heard about this, I recall hearing that once the plane is off the ground the door doesn't get opened for anyone, period and furthermore the only communication between the crew and the pilots is 'there's a problem, we need to land'. This way the plane can't be hijacked since the pilots have no idea what's going on. However, wiki didn't confirm that. I can only assume what I heard was incorrect, misunderstood or changed since 15ish years ago.
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Old 07-13-2018, 10:11 AM
MichaelEmouse MichaelEmouse is online now
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I don't doubt that El Al is nigh impossible to hijack. I don't think most airlines go to quite the same lengths.
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Old 07-13-2018, 10:19 AM
Joey P Joey P is offline
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Originally Posted by MichaelEmouse View Post
I don't doubt that El Al is nigh impossible to hijack. I don't think most airlines go to quite the same lengths.
Probably not. I also forgot something else I saw while reading the El Al wiki page, the floor of the cabin is steel. I assume that's to keep an explosion in the baggage hold from getting in to the cabin.
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Old 07-13-2018, 10:41 AM
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kunilou kunilou is offline
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Without going into too much detail, how bulletproof is the wall between the flight deck and the main cabin?
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Old 07-13-2018, 10:57 AM
Machine Elf Machine Elf is offline
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Originally Posted by Joey P View Post
The first time I heard about this, I recall hearing that once the plane is off the ground the door doesn't get opened for anyone, period and furthermore the only communication between the crew and the pilots is 'there's a problem, we need to land'. This way the plane can't be hijacked since the pilots have no idea what's going on. However, wiki didn't confirm that. I can only assume what I heard was incorrect, misunderstood or changed since 15ish years ago.
Has to be incorrect, at least for long-haul flights that exceed the allowable duty hours for any single crew member. The cockpit crew for the first part of the flight has to come out so the relief crew can take over. AIUI, the flight attendants move service carts into place to block the aisles during this exchange, creating an obstacle that slows the approach of any would-be miscreant, creating time for a crew response. Any sign of trouble, the cockpit door gets closed and no one is going to open it again until things calm down.
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Old 07-13-2018, 11:03 AM
Machine Elf Machine Elf is offline
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In any event, no one would painfully be sucked outside through a tiny bullet hole. That's pure Hollywood.
This. Atmospheric pressure at 35,000 feet is about 3.5 psi. Cabin pressure at 35,000 feet is roughly the same as atmospheric pressure at 6,000 feet of altitude, i.e. 11.8 psi. The difference is 8.3 psi. If you've got a 1/2"-diameter bullet hole in the fuselage, and you plug it with...something, the net force on that object trying to push it out the hole is only 1.6 pounds. You can stick your thumb over the hole and save the day, none the worse for wear.

The situation is much more problematic if you've got a very large hole. 7x10 window blown out? That's 700 square inches, so now you're talking about 5800 pounds of push if something gets into the opening.
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Old 07-13-2018, 11:26 AM
drachillix drachillix is offline
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Without knowing exactly where to shoot and damage some kind of important avionics or data lines that give input to control services or engines, very little. The fuselage and wing skins are not going to be a meaningful impediment to a bullet nor will even dozens of random bulletholes be a threat to the stability of the plane. You could spray an airliner with machine gun fire killing dozens of passengers and the plane can keep right on going.

Even hitting engines would probably do little damage, the engines have a layer of material to stop failed engine components from ripping out and hitting the fuselage, I would imagine that works both directions.
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Old 07-14-2018, 07:15 PM
Tim@T-Bonham.net Tim@T-Bonham.net is offline
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Originally Posted by Joey P View Post
Maybe shooting the engines and hoping the bullets ricochet around just right to cause some of the blades to break off and jam everything up.
I recall reading a story where an Asian woman getting on a plane threw a handful of coins into the jet engine, "for good luck" -- it was NOT good luck, the coins inside the engine damaged it, so the flight was cancelled. (And I believe they billed her many thousands of dollars for the repair costs.)

So it's possible a bullet or several could damage & shut down an engine during flight.

However, that case was the metal coins going into the front air intake of the engine -- it might be hard to get to that firing angle from inside an airplane in flight.

Anyway, airline planes are designed to fly with one or more engines out. Even if they all stop working, the plane can still glide for a long distance, and even land without engines. Remember the airliner that landed safely on th Hudson River with all the engines out?
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Old 07-14-2018, 07:42 PM
Ranger Jeff Ranger Jeff is offline
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They did this on Mythbusters. Bullets can cause the cabin to depressurize but NOT explosive depressurization.
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