Would they even be able to enter the cockpit? IIRC since 9/11 the door to a cockpit is kept locked under almost[0] all circumstances[1]. I am not sure if this holds for all airlines though.

[0]: http://www.theatlantic.com/national/archive/2011/08/how-to-h...

[1]: http://www.latimes.com/world/la-fg-german-jet-crash-door-201...

The cabin crew can unlock the door if the pilots do not intentionally keep the door looked as the Germanwings suicide pilot did.

But that was exactly my point. That:

a) It appears to be standard procedure in the aftermath of 9/11 to keep the cabin doors locked at all times.

b) Many of the cases mentioned where this is useful are cases where the cabin crew are incapacitated due to, say, hypoxia or some other malady.

Given both of these I fail to see how this skill is as useful as others appear to be claiming it to be.

The purser doesn't get any special training, I don't know of any incident on a commercial scale in which the pilot and the copilot were incapacitated or dead and the crew had even time to react.

There were plenty of incidents with small aircraft especially training aircraft where a non pilot had to land it but I don't think anyone untrained was ever in a position to land something as big as 737.

From memory the closest event would be Helios Airways Flight 522 crash, where passage and crew were incapacitated by hypoxia. A flight attendant who was a certified commercial pilot (but without experience on a 737) managed to resist awake thanks to a portable oxygen supply and enter the cockpit.

He even waved at the chase F-16 next to him but one engine flamed out as soon as he entered and the plane started to descend, crashing just 15 min later.

Maybe if he had had more time (and oxygen) he could have managed to bring the aircraft to an airport, but we will never know.

I would imagine they have some sort of existing procedure for this. They could call over the PA and say that the pilot wants to know if there are any GA pilots on board or some other cover story first.

Edit: For what it's worth this was posted on some aviation-specific forums I follow and there are several inaccuracies in the video. It's the person is not a 737 pilot but they may be a commercial pilot certified for some other aircraft, or just someone with a lot of time on their hands.

One thing for sure is they won't use the pa as it will cause panic.

There might be some thing like with doctors where you can register and they'll know you are one but I'm not sure.

For the most part there inst a situation in which you going to have both pilots unavailable and the aircraft isn't going to be plummeting into the ground.