This was suggested on local radio by an engineer. Although he suggested that the autopilot disable code be sent by radio frequency (that changes daily) from ATC.

Actually yes. Nitrous Oxide probably fits the bill the best. No different in flammability than Oxygen, which they already carry on board. Obviously all planes have circuation systems with filters to keep the air fresh.

So, seperate the cockpit air supply from the cabin air supply (and the flight crew still has their emergency mask). This covers the accidental dispensing of N2O affecting the flight deck. Canisters of N2O could be in the filtering network and the caps remotely opened from the cockpit. The gas is odorless which is good and bad. Good in the sense that no one in the cabin, including the hijackers, would know until it was too late and they were losing their faculties and soon consciousness. Bad in case of accidental release, but the cabin crew would figure it out pretty quick. I imagine the failsafes put in place would be fairly comprehensive to protect acciental dispensing.

In the case of UA93 the flight attendant was killed to lure the flight crew out. Here, even though the first casualty could never be stopped, you pop the canisters and wait for unconsciousness. You may lose another casualty or two but the flight crew can't give up the flight deck. The crew then put's down immediately with FBI and SWAT ready to board and take away the unconscious hijackers. Nitrous also doesn't have anywhere near the fine line from unconsciousness to death such as a anesthetic agent like Isofluorane or any others that they typically use surgically.

Obviously they would figure out all the details needed for quantities needed based on number passengers and volume of a specific type of aircraft. But this is certainly not implausible and takes away seriously drastic actions like arming the flight crew. I think the whole goal is keep the flight crew on the flight and the flight deck secure, obviously.

Just my two cents.

If they can get knives on board surely a gas mask could also get past?

Just thinking what's to stop the hijackers from boarding gas masks as a precautionary measure. I guess that would be up to the security check-in folks to ensure that those were not carried on. In any case, all of these security measures being proposed to the airplane will require lots of time to implement.

I think it is really going to be essential that the entire security apparatus works together to minimize risk at every step along the way. A lot of pundits keep saying that security will become lax again in a few months or whenever the American public gets tired of the inconveniences. I have greater faith that the memory of planes crashing into the WTC and the Pentagon will keep viligance high. I hope I am not being overly optimistic.

ScottC wrote:

They'd also have to get the oxygen cannister through.

Tango wrote:
This would cause far more deaths as well as serious spinal injuries than decompression. Decompression would simply force everyone who hadn't passed out to remain seated with drop-down oxygen masks on.

The locked autopilot that would force the plane to land at the nearest airport and lock out all other controls, is a terrific idea (hey Tango, we agree on something!) that is being discussed and presented on other threads. It would seem a cheap solution. I hope it happens.

Edited for UBB coding


[This message has been edited by letiole (edited 09-16-2001).]

FWIW, here is what the California Penal Code has to say about nitrous oxide:

381b. Any person who possesses nitrous oxide or any substance containing nitrous oxide, with the intent to breathe, inhale, or ingest for the purpose of causing a condition of intoxication, elation, euphoria, dizziness, stupefaction, or dulling of the senses or for the purpose of, in any manner, changing, distorting, or disturbing the audio, visual, or mental processes, or who knowingly and with the intent to do so is under the influence of nitrous oxide or any material containing nitrous oxide is guilty of a misdemeanor. This section shall not apply to any person who is under the influence of nitrous oxide or any material containing nitrous oxide pursuant to an administration for the purpose of medical, surgical, or dental care by a person duly licensed to administer such an agent.