Bullet Holes and Rapid Decompression....
- Thread starter Shane Tuttle
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globemaster3
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I missed the original discussion, but from reading here, allow me to throw my .02 in. I think you'll find me qualified for any who google my handle.
Explosive decompression enough to suck someone out of the aircraft who is unrestrained will NOT be done by a handgun regardless of altitude and speed for a commercial passenger carrying aircraft. Not going to be done by a 23mm, even a 57 mm. When you start talking 80-100mm, I might start listening, but it will be more of a factor of the explosive contained in the shell doing the explosive damage more than the hole it made just by entering.
Tuttle is 100% correct when he defined how most airliners and large military acft generate cabin pressurization: off of bleed air from the engines. You just keep pumping air in and regulate the outflow via outflow valves with emergency outflow valves to back the primaries up should they fail so you don't overpressurize. I've had complete seals around doors tear, gap, etc where you could see light through them and we pressurized just fine.
The Aloha Airlines example has absolutely nothing to do with perforation and a whole lot to do with metal fatigue. Again, you are pressurizing a tube to ~8X the outside pressure at altitude to maintain a cabin altitude somewhere below 10,000 feet. On older jets, the schedule was adjusted manually. On newer ones, its automatic. Expand, contract that tube enough times, and it will begin to deteriorate. Stress cracks caused that section in first class to open up.
As far as damaged skin lifting, peeling: highly unlikely at airline speeds. And that skin is more than tin can thick. Next time you board your favorite cattle car, look at the exterior skin around the door edge as you get on. You'll find it's about 1/16" thick. I've seen 23mm hits through wings and fuselage as well as SAM damage flown at 330kcas that didn't even begin to show any sign of lifting. Now, if you go +mach and those edges get shock waves built up on them, then you might have a different problem.
Just my .02.
Explosive decompression enough to suck someone out of the aircraft who is unrestrained will NOT be done by a handgun regardless of altitude and speed for a commercial passenger carrying aircraft. Not going to be done by a 23mm, even a 57 mm. When you start talking 80-100mm, I might start listening, but it will be more of a factor of the explosive contained in the shell doing the explosive damage more than the hole it made just by entering.
Tuttle is 100% correct when he defined how most airliners and large military acft generate cabin pressurization: off of bleed air from the engines. You just keep pumping air in and regulate the outflow via outflow valves with emergency outflow valves to back the primaries up should they fail so you don't overpressurize. I've had complete seals around doors tear, gap, etc where you could see light through them and we pressurized just fine.
The Aloha Airlines example has absolutely nothing to do with perforation and a whole lot to do with metal fatigue. Again, you are pressurizing a tube to ~8X the outside pressure at altitude to maintain a cabin altitude somewhere below 10,000 feet. On older jets, the schedule was adjusted manually. On newer ones, its automatic. Expand, contract that tube enough times, and it will begin to deteriorate. Stress cracks caused that section in first class to open up.
As far as damaged skin lifting, peeling: highly unlikely at airline speeds. And that skin is more than tin can thick. Next time you board your favorite cattle car, look at the exterior skin around the door edge as you get on. You'll find it's about 1/16" thick. I've seen 23mm hits through wings and fuselage as well as SAM damage flown at 330kcas that didn't even begin to show any sign of lifting. Now, if you go +mach and those edges get shock waves built up on them, then you might have a different problem.
Just my .02.
FrankenMauser
New member
Contrary to popular belief, aircraft don't have wires and hydraulic lines spider-webbed across every square inch of the fuselage. The odds of a randomly fired bullet hitting anything important are actually rather low. Airliners, especially, are designed to keep critical components away from the cabin.
Even if your 1 in 1000 chance of hitting a critical hydraulic line were to happen... There are redundant systems waiting to take over.
Wiring... Airliners have so much wiring for creature comforts, it is unbelieveable. Even if you happen to hit some wiring, it's likely to be for the in-seat tv monitors, over head lights, or headphone jacks in the seat. Again - Hitting a critical wire bundle is not likely.
Before anyone brings up a short in the wiring causing a fire... Circuit breakers on aircraft are very sensitive. They sometimes trip just by powering on the system they are supposed to protect. There is a chance of a faulty breaker not tripping, but those odds are also very slim.
Absolutely. I have seen everything from friendly fire 5.56mm to unexploded RPG penetrations. Aircraft are very survivable, and must sustain critical or massive damage to panels to start peeling due to air speed.
The only aircraft we ever lost to hostile fire were all downed by removing the pilots' ability to control it. (Blinded pilots, broken arms, wounds to arms and / or legs, or lucky shots that render the pilot unconcious.) Again; the aircraft survived the damage taken to remove these pilots from the equation. It was the lack of control that caused a loss.
--- For the record, I am not including strikes that hit armor or never hit an area worthy of discussion.---
(Critical areas being the cabin, cockpit, other parts of the fuselage, hydraulics compartments, engines, and any kind of critical electrical devices / wiring.)
Double Naught Spy
New member
No reason for them to stink. You just click the SEARCH button at the top center right and plug in the key words. It doesn't take much in the way of skills to do that. You can learn a lot with basic keyword(s) searches.
I still can't find where pilots were required to carry before 9/11. As for the law change 2 months prior to it, it was a change in FAA regulations that went from allowing guns to be carried to not allowing them to be carried by pilots. However, allowing pilots to carry isn't the same as requiring them to carry and commercial passenger planes often carried mail without armed pilots.
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Technosavant
New member
I never claimed otherwise. I only brought it up as an example of just how much abuse/damage can be suffered to the fuselage and have the airplane hold together. If you can lose that much of the roof, a few bullet holes aren't even going to rate.
Shane Tuttle
Staff
Fantastic. Now, if you will, show me the "several times" this topic has been discussed. When I typed in your keywords, all I came up with was about 3 or 4 in the past 3 years. As I clearly stated, it may have been brought up from time to time on occasion. But it isn't like it's a monthly "here we go again" type of thread that keeps rearing its ugly head.
Correct. Most of your hydraulic lines are routed through the floor. Also, depending on the aircraft, the only major hydraulic lines that are routed forward of the wing is for the nose gear.
There are sometimes up to 3 different hydraulic systems installed on airliners. That doesn't even include the emergency system.
You obviously don't deal personally with the FAA nor do you really know what their operating parameters are. For you to apparantly completely miss the fact that the United States has one, if not, THE safest operating standards in the world for a reason does not deserve a dignified response from me. I'm leaving it at that.
BillCa said:
Actually, the Coke can analagy(sp) is OK to give a person an idea that the aircraft skin isn't exactly thick as a brick. But, to be technical, skin thickness on aircraft can range from .025" on non-pressurized to .062" on mid sized jets. That's not even accounting for the lap joints. Granted, bullets will zing right through even the thicker portions of skin due to being so thin. However, the structural support and the resilient nature of aluminum alloy will remain stable. Even if a "peel" is started by a bullet hole, it will unlikely propagate during flight at high speed.
The designers of composite structures knew what they were doing. Most these structures incorporated in skin and even flight controls are of honeycomb core material. The shape of honeycomb is one of the strongest natural formations known to man. Bees knew what they were doing. Some helicopters use composites for their main rotor blades. The stresses they take on are insormountable. Punch holes in a honeycomb structure and very little structural integrity will be compromised.
I feel even SAFER flying in a honeycomb structure. It would laugh at bullet holes.
globemaster3
New member
Techno, wasn't implying you were saying that, just clarifying for those who might point to that case and say "A ha!" The very fact it landed relatively safely (missing the stewardess and unverifiable 1-2 other pax) is a testament to the design of the aircraft. Once the metal fatigue was understood, it was corrected.
And I agree with Tuttle again on our aviation safety record. Flying around the world, let me tell you, I prefer my home turf from an air traffic control standpoint. As far as inspections are concerned, the airlines perform lots of preventative maintenance as advocated in the manufacturers guidance for the airframe. Late takeoffs or cancelled flights = loss of revenue. Add any kind of crash or mishap attributable to maintenance (or any other factor), and now you have a huge PR problem for that airline = loss of revenue.
Are there weak points? Yes. But its not as bad as seeing the Russian pilots drinking their vodka before boarding their IL-76s or AN-124s!
In terms of bullet damage (and to bring us back to topic), hydraulics aren't the worst of your concerns. Hydraulic fluid in a natural environment is not that flammable. If its misting under pressure from a slight nick, then its a bigger combustable problem. With reduntant systems, loss of 1 hyd system will not cause a huge problem. Fuel is obviously a biggie, but for commercials, most of it is in the wings. A less thought of problem are the oxygen lines that go to those dixie cups in the ceiling. 100% O2 ignitted is bad juju and will cause materials that are normally non-combustable to ignite. See the results from Apollo 1.
And I agree with Tuttle again on our aviation safety record. Flying around the world, let me tell you, I prefer my home turf from an air traffic control standpoint. As far as inspections are concerned, the airlines perform lots of preventative maintenance as advocated in the manufacturers guidance for the airframe. Late takeoffs or cancelled flights = loss of revenue. Add any kind of crash or mishap attributable to maintenance (or any other factor), and now you have a huge PR problem for that airline = loss of revenue.
Are there weak points? Yes. But its not as bad as seeing the Russian pilots drinking their vodka before boarding their IL-76s or AN-124s!
In terms of bullet damage (and to bring us back to topic), hydraulics aren't the worst of your concerns. Hydraulic fluid in a natural environment is not that flammable. If its misting under pressure from a slight nick, then its a bigger combustable problem. With reduntant systems, loss of 1 hyd system will not cause a huge problem. Fuel is obviously a biggie, but for commercials, most of it is in the wings. A less thought of problem are the oxygen lines that go to those dixie cups in the ceiling. 100% O2 ignitted is bad juju and will cause materials that are normally non-combustable to ignite. See the results from Apollo 1.
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Wildalaska
Moderator
Even more evidence here for why I hate flying. Coke cans at 35,000 feet. Puke puke
WildOHGAWDGETMEOUTOFHEREsorryImundercontrolnowAlaska TM
WildOHGAWDGETMEOUTOFHEREsorryImundercontrolnowAlaska TM
FrankenMauser
New member
I completely missed the composites-in-aircraft reference.
I REALLY hate to say it because everything about the "aircraft" makes me want to vomit... However, I have had some limited experience with the MV-22 Osprey. Damage to the composite structures (almost the entire bird) are actually less detrimental than to similar aluminum structures on other aircraft. Certain survivability ratings are even double to triple that of planes or helicopters that could be compared to its capabilities.
I really prefer to feel cold metal around me, when the machine is the only thing between myself and a 12,000 foot fall. But... what I have seen of the Osprey has really opened my eyes to the composites engineers.
If I had to make a wager on which was more damaging; a bullet hole in aluminum or a bullet hole in modern composites; I would put my money on the composite structure holding up better.
Modern composites are amazing. It's a shame the general public cannot see some of the high-tech stuff the military is using now.
Just don't set the things on fire.....
I REALLY hate to say it because everything about the "aircraft" makes me want to vomit... However, I have had some limited experience with the MV-22 Osprey. Damage to the composite structures (almost the entire bird) are actually less detrimental than to similar aluminum structures on other aircraft. Certain survivability ratings are even double to triple that of planes or helicopters that could be compared to its capabilities.
I really prefer to feel cold metal around me, when the machine is the only thing between myself and a 12,000 foot fall. But... what I have seen of the Osprey has really opened my eyes to the composites engineers.
If I had to make a wager on which was more damaging; a bullet hole in aluminum or a bullet hole in modern composites; I would put my money on the composite structure holding up better.
Modern composites are amazing. It's a shame the general public cannot see some of the high-tech stuff the military is using now.
Just don't set the things on fire.....
Ken, You need to join my older brother in the airport bar and contemplate the fine subtlties of a few single malt scotches before take-off.
As for me, I kinda liked flying upside down at Mach .94 at 500 feet over the desert. (Ejecting would've be a b**** though!)Uh-huh. Tell that to the passengers and crew who were on United Airlines Flight 232 in 1989. After engine #3 initiated an in-flight self-disassembly in the tail and took out all the hydraulics for the flight controls, that DC-10 turned into an occupied 350,000 pound buzz bomb. At least, right up until they managed to plow up the corn fields next to Sioux City Airport.
Actually, that semi-controlled crash resulted in a 62% survival rate - which is excellent for airplane crashes. However, it's not quite as good as the 67% survival rate of those who survived another filmed crash - the 1937 crash of The Hindenburg.
Actually those O2 lines are fairly short. Behind each set of masks is a small chemical oxygen-generating canister. When activated it provides oxygen for about 15-20 minutes at a steady rate. The canisters are about 2.5" x 8-10 long or about the size of a tube of Pillsbury breadsticks.
Not always. American Airlines Flight 191 was the DC-10 that lost it's #1 engine during takeoff from ORD (Chicago O'Hare) in 1979. When I say lost, I mean it literally broke the pylon and flew up over the wing, lost. That incident was traced to faulty maintenance "shortcuts" by AA in their Tulsa facility that caused damage to the pylon mounts. United (UA) and Continental used similar procedures until the FAA halted the procedure.
Someone made the point earlier that the aircraft's cabin structure is mostly empty space WRT critical systems. Where the wings carry most of the fuel and need to have control systems, the fuselage, by volume, carries very little.
When Diane Fienstien made the outrageous comment that a .50 BMG rifle could take down an airliner, she had no clue what she was talking about. First, making a hit on an airplane from several hundred yards while it is either ascending on take-off or descending on landing (and changing speed) would require very great skill.[1]
Just making a hit won't do it though. You have to hit something critical. An engine is a nice big target. But chances are that if an engine fails, the flight crew can generally recover the aircraft due to their intensive training for losing an engine during TO/LDG. And hitting an engine on a plane landing means predicting wing-level attitude which changes second to second.
Hitting the flight deck or the main flight control system equipment below deck.[2] would be equally challenging. It would be like hitting an empty soda can swinging in a gusty breeze at 1,000m reliably every time.[3]
[1] This presumes that one could find a suitable location near the landing approach to set up a sniping position well enough in advance and not be detected by an observer.
[2] Even hitting the electrical or hydraulics system in the aircraft's below deck centerline is complicated by the enormous amount of freight and baggage carried in metal LD containers.
[3] Even with lead computing optical sights (LCOS) most gunfire initially misses the target aircraft, with tracer rounds allowing the pilot/gunner to adjust his aim. Here we're talking a bolt action or semi-auto rifle, in a windy environment, making reliable spot-on hits against a target that is constantly changing distance, speed, altitude and attitude. That's about as likely as Diane Fienstien winning a spring-break bikini contest.
chemgirlie
New member
I watched Goldfinger last night. Ah, I love life's random coincidences.
Several times during the movie Connery makes references to catastrophic decompression. However, this is just Hollywood. Unless there was a MASSIVE section of the airplane that departed from the rest of the plane very quickly, the scenes of people being sucked out of planes will only happen with the aid of Hollywood special effects.
Several times during the movie Connery makes references to catastrophic decompression. However, this is just Hollywood. Unless there was a MASSIVE section of the airplane that departed from the rest of the plane very quickly, the scenes of people being sucked out of planes will only happen with the aid of Hollywood special effects.
When I went through the LEO "flying armed" class a few months ago the only really big warning/concern was don't shoot at the floor or the cockpit if you can possibly help it. Decompression is not an issue but there's tons of wires, hydraulics, etc. under the floor and, while the cockpit door/wall is supposed to be reinforced, there's no sense in taking a chance since you're probably going to need the flight crew. Other than that anything goes, do whatever it takes to make sure that NOBODY gets in the cockpit.
fisherman66
New member
I keep a can of "fix-a-flat" on me when I can smuggle it past the checkpoint.
carguychris
New member
I'd like to see a citation in a mainstream, reputable publication to back this up.
I'm aware that mail handlers in some transportation-related jobs used to be required to carry sidearms prior to the mid-20th century. However, there's a big difference between the people who unload the mailbags and the people on the flight deck.
Never in my many years as an aviation junkie have I ever read that U.S. flight crewmen were required to carry sidearms for any reason. Allowed, yes; required, no.I'll wait for the answer.
Wildalaska
Moderator
yeah, great, 20 year old McCallan spewing out my nose.
The only thing worse than flying is a scotch puke (of which I am highly familiar due to my younger days)
Huueeeeeeeeeeeeeeeeey....*wipesnort* :"hey yo, Air Marshall, fer gawds sake shoot me...don't hit a hydraulic line ok"
Wildnothing isworsethana53yearoldfathairybabywithscotchdribbleAlaska ™
Shane Tuttle
Staff
While I must say your suggestion is quite boorish and the probability of understanding my point is unknown, I will still respond:
1 .Since you’re an advocate of handgun ownership, would you tell your testimony to some families that lost a loved one due to an incident with a handgun?
2. How about telling the whole story behind the likelihood of being killed by a handgun compared to dying in a plane crash that lost all three hydraulic systems? If you want a ballpark probability rate of the aircraft scenario, just look at the link you provided.
3. Tell me what this has to do with rapid decompression due to bullet holes in the cabin.
4. Do you know what measures were introduced by the FAA and NTSB that will keep this from happening again? What steps have gunowners taken to assure a handgun incident won’t take a persons’ life? Before you answer, be sure to note steps taken that were as effective as the said aviation incident.
No need to "look up" any of it, Noeyes. Contrary to your apparent view on the FAA, needless drive-by posts that don't have anything to prove against my original point, and dubious knowledge of aviation in general, I happen to make a living in this industry and actually know a thing or two about the big picture. My question to you is basically the same as the one I addressed to BillCa: What does your claim to fame have to do with the price of tea in China?
Back in the 70's when several airliners were hijacked and diverted to Cuba, some of us discussed this over pizza and beer (brain food, of course). Our solution was to arm willing adult passengers with a single-shot .25ACP pocket pistol. By itself hardly worth calling it a gun. But as soon as the hijacker committed himself, 133 angry people open up on him with results like buckshot.
Yeah...completely impractical.
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