During World War II aircraft sometimes carried wire recorders. These allowed post-flight monitoring of their radio transmissions. By 1958 the flight recorder came into regular use. This device can continuously record information such as altitude, pressure, airspeed, and some control surface positions. One of the main advantages of this unit is that it is safeguarded from fire, water, and impact. With the resistance to impact the flight recorder has become invaluable in its assistance with the diagnosis of aircraft crashes. There are various designs in flight recorders which range in complexity, dependent on the class of aircraft. In some lightweight aircraft there is no recorder at all. However, many countries insist that the aircraft has at least a cockpit voice recorder (CVR). These units provide a recording of the radio transmissions which take place. Most aircraft of a commercial or military nature make use of an aircraft integrated data system (AIDS).
An AIDS can contain many thousands of components which control the main functions. Examples are the flaps, air conditioning and landing gear. The engines have the ability to tell the AIDS how they are functioning and what they have been programmed to do. The engines can have up to 24 sensors which can extract information and pass it to the flight recorder. The aircraft integrated data system can be linked to an air data system, a navigational system, the basic flight control system and also the very important communication channels. The flight recorders are protected in such a way that they can survive seemingly impossible conditions. The adverse states which can be encountered such as white heat (temperatures above 1200 Centigrade, 2200 Fahrenheit) do not effect the recorder at all.
With the introduction of flight recorders, the records obtained have allowed the working life of aircraft components to be judged much more successfully than ever before. The systems can also forewarn of any failures or malfunctions which may possibly occur. This is done by observing the previous records accumulated on any one aircraft. If required, the necessary adjustments can be undertaken with confidence in advance of them ever actually becoming a real threat.
