I have been told that today it would be very difficult to hijack a plane knowing with what we know as you as a PIC could simply just dump cabin pressure and put every one behind you to sleep.
by the time Ahmed wakes up you could have him in flexcuffs.
would this be a viable feat?
In theory it could be done. In practical application probably not...and it would be foolish to do so IMHO.
Intentionally dumping cabin pressure places everyone on board at some risk.
And of course that places the airline, and the pilots involved as some level of liablilty risk. Kinda like when the Russians gassed all those people in the theater to put the kidnappers to sleep and ended up killing quite a few hostages in the process.
The hijackers are coming in with a plan. In the time they attempt their breach, a pilot would have to go from "What the F@#$ was that?!?!" to DON the O2 mask and dump the cabin pressure.
That could/would take some time unless the pilot is constantly in Condition Red (and then he's one of those guys no one else wants to share the flight deck with
) with one hand on his O2 and the other on the dump switch.
Furthermore, most transport category aircraft have both a automatic and a manual pressurization mode. Auto is the standard setting. In the aircraft I fly, if you dump the cabin in auto mode it actually only takes the cabin up to an altitude of 14,500' (from 8,000') and if the hijackers are in decent shape, they may slow down a little bit but they aren't gonna konk out.
In order to dump the cabin completely you'd have to go to manual and then run the outflow valves full open which adds more time to the pilots reaction -- then the cabin would climb, but it would not be instantaneously.
Now if these guys were just killing people in the back but had not attempted to breach the FD well then it could be an option in theory........but the practice has been advised against by most every airline managment as well as the Air Line Pilots Association.
Todays FD doors are bulletproof but not necessarily breachproof although they have various locking mechanisms, most of them are only going to slow a breach attempt rather than prevent it. One could only hope that the able-bodied passengers get involved while the one of the pilots initiates an Emergency Descent and the other maintains the integrity of the FD and FD door and prepares to defend it with use of deadly force.