How mechanically reliable are aircraft?
Aircraft are perhaps some of the best examples of over-design in engineering. A factory-built airplane must meet rigid FAA design criteria and performance specifications. Each design is tested throughout its flight envelope, and a safety margin is then built in. For example, the structure of a typical training aircraft is certified to withstand 4.4 positive Gs. This means that if the airplane and contents weigh 2,000 pounds in normal level flight, the structure can safely handle up to 8,800 pounds in turns and pull-outs from dives, where the weight increases from centrifugal force. In routine flight, a pilot will usually not exceed 2 Gs. There are very, very few accidents caused by an aircraft just coming apart, and this is easily prevented. The leading cause is where the pilot overstresses the aircraft in a pull-out or exceeds the top (redline) airspeed. In an automobile, if you over-rev the engine or take a corner too fast, you’ve exceeded the car’s envelope. The vast majority of dri
