How many times does this myth have to be de-bunked?

[Mudge]

OK...there was an accidental discharge of a handgun on board a US Airways plane. TSA hasn't released the details as to why. But here's what, (they're calling) an "expert" says about it,

"The TSA has never been real supportive of this program," said Mike Boyd, who runs the Colorado-based aviation consulting firm The Boyd Group. "It's something I think Congress kind of put on them."

Pilots must volunteer, take a psychological test and complete a weeklong firearms training program run by the government to keep a gun in the cockpit.

Boyd said he supports the program to arm pilots, saying, "if somebody who has the ability to fly a 747 across the Pacific wants a gun, you give it to them." But he said Saturday's incident could have been much worse.

"If that bullet had compromised the shell of the airplane, i.e., gone through a window, the airplane could have gone down," he said.

Like I said, how many times does this myth have to be "BUSTED"?

Mudge the mythical

[Cvairwerks]

While causing a catastrophic failure is possible, the probability of every thing necessary coming together to allow it to happen is so remote that the odds have lots of zeros before the decimal point. Unfortunately the movies and the images that the reporters want to convey sell a lot more copy than the truth.

It's too bad that histerics and chicken littles seem to have more influence on people than reality. It gets somewhat depressing when you have people believe that type garbage without even a second thought or questioning it. Common sense and thoughtful caution has been bred out of the newer generations it seems.

[T2 Ernie]

I assume you're referring to the "bullet through the skin/window" taking down the plane.

While looong odds, they are real. Granted, it is apparent that the copy writer seized upon this remote possibility and used it in dramatic fashion, but it's possible depending on where in flight you are.

Way up high in the mid-upper FL300s, time of useful consciousness is measured in mere seconds & lessened significantly (unable to put a number to it due to various reasons) if it's a rapid decompression due to a window blowing out. When everyone takes a hypoxic nap inside of 20 seconds - the pilots better be ready with their sweep-ons. Think Payne Stewart & his plane's crash.

We've done leaflet drops at FL330 and higher with the plane unpressurized - it's amazing how quickly guys fall over when their hose comes unplugged. We've got phys-techs onboard & ready with stand-alone supplemental O2 until they can get their hoses hooked back up. And this was with pre-breathing 100% O2 for an hour or better...

So while you're technically correct - the bullet probably won't take out the plane, but it could take out the crew which would have the same results. The mitigation is the crew's training - the practice of emergency procedures in the simulator.

I won't address the even more remote possibility of hitting a non-suppressed fuel tank or dry bay...

[Cvairwerks]

Actually Ernie, I wasn't even thinking of that at all. I was looking at the circumstances all lining up so that the round cut down a section of unsupported part of the skin, working like a nibbler and allowing a flap of skin to be torn ala Aloha Air... Crew incapacitation due to whatever reason is a whole 'nother thing. Stewart's crash was probably in the makings as soon as they reached enough altitude that the outflow valve failed to properly close and not allow proper pressurization.

BTW...I assume that you have seen the pics of the KC-135 ground pressurization failure? Gives a whole new meaning to "It was a blast"

[Mudge]

I was referring to the standard "bullet through the window/skin" leaving a .45 cal. hole. Not all the extreme circumstances that could, on an odd numbered Tuesday at 0300 and at 31,260 ft. create a catastrophe. God Lordness people.

Mudge the simplistic

[T2 Ernie]

Oh gosh no - holes in airframes? Hmmm...I've come home with more than I left with very glad that holes alone don't take out a plane... Holes in the wrong places can be very, very bad, but we're back to golden BBs.

Golden BB theories aside, I think the greatest danger in this scenario is rapid decompression & subsequent crew incapacitation though...but you'd need a secondary failure - the .45 cal hole itself wouldn't cause rapid-D. Front windscreens would likely survive well enough too - pax compartment windows might not.

But it looks good in the movies when a bad guy shoots a hole in the plane & it blows out a window & people get sucked out!

Agree on Payne's plane - just using the hypoxia aspect of that to illustrate the point. Can happen very, very quickly at altitude.

I wonder how a composite skin would react to an exit wound while pressurized though...


Ernie the partially hypoxic (I live at 7000')

[CAPFlyer]

Actually, Mythbusters used a DC-9 passenger window (albeit with a 9mm) and it survived just fine.

Additionally, most of those carrying in the cockpit are using frangible ammunition, there's a good chance that the round wouldn't even penetrate the window or aircraft structure because it would break up once it entered the first pane of plexi or the interior wall.

[bdk]

I wonder how a composite skin would react to an exit wound while pressurized though...

No difference... Composites are designed/analyzed with an assumed flaw in the laminate in case someone loses their watch in the layup.

[corsairdude]

On this particular incident, I recall the plane was close to landing and that means the pressurized cabin setting was very close to the outside pressure. So even if they had lost a window or some other large-size part, no explosive decompression was posible. Sure, they would get a lot of noise in the main cabin but thats about all.
On regards to hypoxia, it´s true Time of Usefull Consciousness TUC is greatly reduced at altitude, but this is not the case here.

[T2 Ernie]

Agreed, CorsairDude - reports are saying they were at 8000' or so. However, the issue was whether or not a round could take out an aircraft. I caveated my example with very specific criteria. (see my above post about holes in planes - those are all at low altitude)

CAPFlyer - was the DC9 pressurized? If not, that certainly changes the dynamic significantly. 9mm almost doesn't even count as a round either!

We carry hollow-point for anti-hijacking precisely for that reason - ball ammo is much more likely to continue its journey with enough mass to damage something after the first contact with something...this despite the fact hollow-point are generally barred in routine military use.

I've got a friend in the pilot carry program who works for a major airline - I'll ask him some questions...

[Jack Frost]

There's a more important issue here besides how big a hole the bullet made. In Airline operations, anytime you're below 10000' a sterile cockpit is mandatory. This means no distractions that aren't directly connected to flying the aircraft safely, period. This crew was below 10000 and somebody was handling the weapon. Why? Packin' up the gun so I can leave the cockpit quicker at the gate? Possibly. Just messin' with it? Possibly. If there was a highjacking in progress we would have heard about it by now so it would appear that any other reason would be grounds for an FAR violation.

I've got a friend in the pilot carry program who works for a major airline - I'll ask him some questions...

Ernie, if you're not part of the pilot carry program your friend has no business passing on any of the details and might well be in violation of the pilot carry regs. Posting any info on WIX might well be a TSA violation.

[corsairdude]

Just read the pilot was stowing the gun when it went off. He wasn´t playing with it or showing off with the stews.

[bdk]

Photos of the "exit wound" here:



http://news.yahoo.com/nphotos/US-Airways-US-Airways-flight/photo//080325/480/e45d7ad66aec436dbdbb24ba6fb9bc8a//s:/ap/20080327/ap_on_re_us/gun_on_plane;_ylt=Aqwi6jutNKerbej1d2q85ydH2ocA

http://news.yahoo.com/s/ap/20080327/ap_on_re_us/gun_on_plane;_ylt=AmDN2y0ZcPSL99PzYmpsw.RH2ocA

[T2 Ernie]

Ernie, if you're not part of the pilot carry program your friend has no business passing on any of the details and might well be in violation of the pilot carry regs. Posting any info on WIX might well be a TSA violation.

Awww, c'mon - I've got a much higher security clearance than he does! ...guess it's down to need to know, eh? (I understand that one!)

Thanks for the tip - won't ask him anything.

[bdk]

From AvWeb:

Some Pilots Blame TSA For Cockpit Gunfire

The Airline Pilot Security Alliance (APSA) Thursday released a statement saying that TSA weapons-handling rules are to blame for the accidental discharge of a pilot's firearm while in the cockpit of a flying US Airways jet last weekend. The APSA pointed specifically to the TSA's requirement for pilots to remove the guns from their person, lock them and carry them "off-body" when off the flight deck. The group quotes an unidentified federal flight deck officer who said the pilot involved was preparing for landing and was trying to remove his gun and secure it when "the padlock depressed the trigger." Personal responsibility aside, the rules may force some pilots to handle their guns ten times each day and that much gun play is "a recipe for disaster," according to David Mackett, president of the APSA. APSA's press release concluded with one pilot's opinion that Congress should take a look at how the program is operated, and the suggestion that pilots should follow the same procedures applied to federal air marshals.