On the other hand, if the mushroom eater had been an FFDO…
Exactly. It cuts both ways.
One of my pals is an FFDO for the right reasons, not the wrong ones. He found it pretty sobering to consider having to execute that guy on the spot.
Just thinking about the limited cubic feet in a cockpit … wouldn’t the (inarguable) need to discharge a handgun virtually ensure hearing loss for all who survived?
No. I’m not suggesting there would be a viable alternative…
Everyone in the cockpit is gonna be hearing impaired for a couple / few minutes. The same thing is true for police who fire their pistol outdoors in the course of a day’s work. They’re very loud, but not instant, permanent, irrecoverable hearing loss loud.
The cockpit is a small space, but it’s not a sealed small space. There’s lots of airflow in and out which means lots of openings for the pressure wave(s) to escape through. Will it be worse in that semi-enclosed space than outdoors? Yep. Same thing is true if a cop fires their gun in a bathroom versus in a parking lot.
Back when I was shooting pistols regularly I made a point of every few sessions firing one last round without hearing protection. Just so the first time I heard that noise for real wasn’t when I was firing at somebody for real and needed to keep concentrating for the subsequent shot(s). That wasn’t good for my hearing, but as a fraction of my total lifetime noise exposure it also wasn’t a huge fraction. Been a couple decades since I last shot anything though.
I just know you guys are posting this stuff because I’m flying over the Christmas/New Year holiday. 
What happens if one of the bullets misses its target and hits one of the windows? Would the window be strong enough to take the hit, or would there be a crack/hole that leads to depressurisation?
And soldiers in combat. When it’s life-or-death, you do what you gotta do, even if it means some hearing loss.
My gut feeling is that since the cockpit windows are double-paned and thick enough to tolerate a birdstrike, they’ve probably got a better chance of stopping a bullet than the thin aluminum skin of the fuselage itself. However, caliber matters; 737 windows can’t stand up to a 50-caliber sniper rifle, but I bet they might tolerate a .22 pistol round.
ETA: partly ninja-ed by @Machine_Elf while I was typing. He makes the excellent point that guns (and bullet designs) vary greatly in their penetrating power.
Interesting question. What follows is informed speculation, not proven fact.
The cockpit windows are very, very strong and very, very impact-resistant. They aren’t bulletproof. So the bullet will end up outside which means there will be a hole. They’re made of 3 (sometimes two) layers and it is common enough for the outer super-glass layer to shatter. Accumulated stress from thermal expansion & contraction, occasional bird impacts, etc, and sometimes one just lets loose. Which is alarmingly loud and unnerving, but not dangerous. The middle polycarbonate layer is the strength layer. Following an outer-layer shatter there’s no leak and no pressure loss. Flying though hail is almost sure to shatter an outer layer (and do a lot of other damage to the jet too). All jets have an emergency response procedure for window shatters. Some airplanes have restrictions like go down or slow down some; others are fine at full altitude and full speed with an outer layer shattered.
Here’s some pix: airliner windshield shatter - Google Image Search.
Now a bullet getting outside will of necessity have gotten through all the layers. My bet is the middle layer will end up with a neat hole in it, but hold together. I expect tests were done before the FAA agreed to armed folks in the cockpit. I don’t know what sort of ammo FFDOs use, but it’s probably designed for close-quarters anti-personnel use which suggests bullets designed for max mushrooming / break up and min penetration.
A bullet-sized hole will result in a lot of air noise, and some immediate pressure loss. At high altitude the normal cabin overflow valve is partly open with a cross-section anywhere from a human palm to a dinner plate depending on the size of airplane. It closing slightly to offset a fresh 1/2" or even 1" diameter hole is perfectly doable. By the time the humans have figured out what happened, the pressurization anomaly will be contained.
If the whole pane lets go and now you’ve got 2x2 feet or more open to the outside, now we’ve got a whole new problem. The airplane will depressurize completely and over the space of just 10-15 seconds. Oxygen masks and the rapid descent procedure are the very next right-now-this-instant order of business.
In many ways I’d rather take a bullet through the windshield than through the overhead control panel or forward facing instrument panels. it’s a very dense tangle of vital stuff and vital wiring there and random damage to those areas might result in a very hard to fly airliner and perhaps even a very hard to stop electrical fire. Fire in the electrical system in the cockpit are the nightmares that get pilots suddenly bolt upright from a sound sleep drenched in sweat & breathing hard. In some random hotel room somewhere. BTDT, no fun.
During the course of this hijacking and ground-hostage situation Air France Flight 8969 - Wikipedia the commandos stormed the plane to end the siege. One of the commando’s tasks was to barge into the cockpit and spray the forward instrument panel with his machine gun. To utterly and instantly render the airplane unflyable. It worked. Didn’t help the pilots’ state of mind much, nor their hearing. But they survived.
Weird. I was very much under the impression for years now that anything an Air Marshal or armed pilot would carry on a plane would be subsonic ammo specifically to minimize damage to the airplane. I can’t seem to find any cite for it now, so maybe I was misinformed years ago and carried that misunderstanding around for years.
In a plane traveling 5 or 600 miles per hour, using subsonic ammunition, it could take quite some time for a bullet to hit a bad guy half-way down the length of the airplane cabin (depending on whether you fired in or against the direction of travel).
/s
This is from ~15 years ago:
The “expert commentator” Mike Boyd is a well known idiot full of stupid and sensationalist notions. The media loves to quote him and he loves to be quoted. Any connection between reality and his ideas is simply coincidental.
I recall an event that occurred a few years ago to somebody parked at the gate. In the course of holstering / securing (or vice versa) the gun, it fired and drilled a neat hole in the sidewall of the airplane below the side cockpit window. Expensive to fix, but no major excitement.
I’d find a cite, but the first 23 pages of google results are tied up with the case this thread is about, crowding out all the prior year’s news.
More likely frangible ammunition.
So … yeah. It was the COVID vaccine. The one he refused. That’s why he was relieved of his command as an Air Force Reserve Lieutenant Colonel:
He is the same Jonathan Dunn who unsuccessfully sued the Pentagon to prevent the Air Force from disciplining him for refusing to receive a mandatory COVID-19 vaccination
Dunn objected to the vaccine on religious grounds.
How’d we not see that one coming??
Dunn was afterward sent on orders to Ramstein Air Base in Germany, training to serve at the 603rd Air Operations Center. The Air Force has suspended his access to sensitive information and to the air operations center because of the airline incident, according to a spokesman for the Air Force in Europe.
Phew. So good that they didn’t miss that 
Are you telling us that “pilot flatulence” can blow out a cockpit window???
Isn’t that the basic physics behind JATO?
I’m not sure if this is supposed to be a joke, but just in case I’m not being whooshed, no. If the shooter is in the plane, the speed of the plane is irrelevant. Some guy named Gallileo explained this a few years ago.
Wouldn’t the plane crew get overtime if the plane diverted? Drop off the sick passenger and resume the scheduled flight?
I can’t see why the co-pilot gave a crap about a plane diversion. 
He might be irritated to get off work late, but pulling a gun?
Seems like we’re not hearing the entire story. Maybe these two men had prior arguments? Some bad history between them?
Now who’s joking. You can’t fool me, there were no jet aircraft in Galileo’s time.
Did you miss the “/s” tag at the bottom?
Obviously there is no divert-related situation that justifies pulling a gun. Upstream from that dumb move …
There are a number of ways diverting can become a significant hassle for the crew as individual people. None of which should affect their decision, but some folks are not always as professional as they should be.
-
They’re supposed to finish just before the last rapid transit home. It’ll cost $100 to uber home if they’re late. BTDT myself, except it was $150.
-
They’re supposed to finish just in time to go with the family to see their kid’s big soccer game, dance recital, or whatever. The one they’d promised the kid they’d make since they missed the kid’s last four big events due to work. BTDT, although it was expensive theater tickets with my wife.
-
If they divert, they’ll be stuck there overnight due to crew legality. Tomorrow morning they’re planning on leaving on a 2-week cruise and can’t miss that departure. I never planned vacations that tight but I certanly flew with folks who did.
-
If they divert, the extra time gained and late arrival means they’ll become illegal to fly their next trip going out tomorrow. Which means they’ll be removed from the trip at no pay. And somebody else will work it. Which removal will cost them several thousand dollars of lost wages, includes a great layover someplace, or is where their girlfriend lives. Or all three. BTDT many times, but not the GF part.