Defenses in Depth - Continued

Ideally, each defensive layer would be impervious. But in reality, the layers are like slices of Swiss cheese with holes that continually open, close, and shift location. When accidents occur, the holes from many "slices" momentarily line-up allowing a hazard to come into contact with a protected asset.

These layers of defenses are key to the systems approach. Aviation systems have many defensive layers, some are engineered (alarms, fail-safe designs, redundant systems, automated functions, etc.) and others are reliant on people and procedures (pilots, mechanics, controllers, administrative controls, etc.). The aviation system is extremely safe, but there are always weaknesses.

Select Next to continue.