Pertinent Logic
Of all the methods being proposed for dealing with a psychopathic pilot in the cockpit of airliners, only one method is considered to be, for the moment at least, rationally viable; it's known as "the rule of two." That is, no less than two aircrew will occupy, at any time, the cockpit of an airliner — gate to gate.
What makes the "rule of two" so viable? There is a very rational answer to that question. The answer is that it is highly improbable that more than half of the persons in the cockpit will be psychopathic.
The logic used in the "rule of two" is the same logic used in having an armed citizenry. The hypothesis is that, should the need arise, there will be someone in the immediate vicinity who is capable of "taking command" of the situation. It's logical, and it works.
A few years back, I put forward a hypothetical question to some of my students regarding an incident somewhat similar in nature to the recent Germanwings case.
On the afternoon of December 7, 1987, Pacific Southwest Airlines (PSA) Flight 1771 lifted off the runway at Los Angeles International airport, bound for San Francisco. There were 43 people aboard.
According to the story at Wikipedia, it was a beautiful, cloudless day; the reported visibility was 50 miles.
Suddenly, at 4:13 p.m., the pilot reported to air-traffic control that he had an emergency, and that gunshots had been fired in the airplane. Within 25 seconds of the pilot’s last words, the controllers observed PSA 1771 begin a rapid descent—a dive from which it never recovered.
At the time, USAir had recently purchased, and was in the process of absorbing, Pacific Southwest Airlines. David Burke was a former employee of USAir. Burke had been terminated by USAir for petty theft from an airline fund and, after meeting with his supervisor, in an unsuccessful attempt to be reinstated, he purchased a ticket on PSA 1771, a daily flight from Los Angeles, California to San Francisco. Burke's supervisor, Raymond F. Thomson, took the flight regularly because Thomson lived in San Francisco but worked at Los Angeles International Airport.
Using his old USAir credentials, and armed with a borrowed .44 Magnum revolver, Burke was able to bypass the security checkpoint at Los Angeles International Airport.
After boarding the plane, Burke wrote a message on an air-sickness bag. The note read: "Hi Ray. I think it's sort of ironical that we ended up like this. I asked for some leniency for my family. Remember? Well, I got none and you'll get none.”
As the plane cruised at 22,000 feet over the central California coast, Burke left his seat and headed to the lavatory, dropping the note on Thomson's lap. As he exited the lavatory a few moments later, Burke took out a handgun and fired twice at Thomson, as the cockpit voice recorder later confirmed. He then opened the cockpit door. A female, presumed to be a flight attendant, told the cockpit crew that "we have a problem." The captain replied, "What kind of problem?" Burke then appeared at the cockpit door and announced "I'm the problem," simultaneously firing three more shots that probably killed the pilots.”
A few seconds later, the cockpit recorder picked up increasing windscreen noise as the airplane pitched down and began to accelerate. A final gunshot was heard and it is speculated that Burke fatally shot himself. The plane then descended and crashed into the hillside of a cattle ranch at 4:16 p.m. in the Santa Lucia Mountains near Cayucos, California.
It was determined several days later by the FBI, after the discovery of both the handgun containing six spent bullet casings and the note written on the air-sickness bag, that Burke was the person responsible for the crash.
Now for my hypothetical question: if one or more of the passengers, besides Burke, had been carrying a concealed weapon, do you think that Flight 1771 would have crashed?
Given the above circumstances, it seems probable to me that Burke would have never made it into the cockpit, and the plane would NOT have crashed. Granted, there would have probably been some holes, but nothing like Aloha Airlines Flight 243 that lost the top of the cabin... And, it is likely that Flight 1771 would have landed safely.
That's the way it's supposed to work.
/fl