View Full Version : Security - A New Approach

14th Sep 2001, 04:14
There has been much discussion on airline security. I suggest using a different approach to the problem may allow us to see solutions in a different light:

Multiple defenses, not one layer

The idea here is to have, say, three layers. If each layer has a 99.9% success rate (ie, 1 in 1000 bad people get through each layer), then the total system has a 99.9999999% success rate (ie, 1 in a billion bad people get through all three defenses).

The three layers could be, for example, passenger identification and screening, baggage (hold and carry-on) screening, and a permanently locked, armoured cockpit door.

No doubt there are many other ideas. Remember the aim here is not one solution, but many layers.

Passive defenses, not active

A passive defense is preferable to an active defense for many reasons. "Passsive" means an automated, 100% cover which only requires minimal, preferably zero, outside human action. It works all the time, automatically. An example of a passive defense is a permanently locked, armoured cockpit door, never to be opened while in-flight for any reason.

An "active" defense is one which requires continuous, or near-continuous, human interaction. Armed sky marshalls is an example. The problem here is that humans are very bad at monitoring. Sky marshalls will get bored, become complacent; their skills will need continual practice and supervision. All of this makes an active system much more expensive, and much more prone to failure, than a passive system.

Are X-ray machines, used to screen carry-on luggage, active or passive? At the moment they are probably active, as they require an alert human to visually check the screen. We've all seen how tired some of these people get, and being human they will make mistakes. To improve this, computer recognition programs are required so that the human is only required when the computer is in doubt. This is technically very difficult today, but who knows about tomorrow. I am using this as an example of the differences between an active and passive system, and why the passive is better than the active.