Observer's Directory of Military Aircraft

When spotting aircraft, observers generally notice the key attributes of an aircraft, such as a distinctive noise from its engine or the number of vapour trails it is leaving. Observers assess the size of the aircraft and the number, type and position of its engines. Another distinctive attribute is the position of wings relative to the fuselage and the degree to which they are swept rearwards. The wings may be above the fuselage, below it, or fixed at midpoint. The number of wings indicate whether it is a monoplane, biplane or triplane. The position of the tailplane relative to the fin(s) and the shape of the fin are other attributes. The configuration of the landing gear can be distinctive, as well.[1] Other features include the speed, cockpit placement, colour scheme or special equipment that changes the silhouette of the aircraft. Taken together these traits will enable the identification of an aircraft. If the observer is familiar with the airfield being used by the aircraft and its normal traffic patterns, he or she is more likely to leap quickly to a decision about the aircraft's identity - they may have seen the same type of aircraft from the same angle many times. This is particularly prevalent if the aircraft spotter is spotting commercial aircraft, operated by airlines that have a limited fleet.[citation needed] Spotters and photographers enjoy seeing aircraft in special colour schemes. Both of them read and process the radar data and show the movements on a computer screen. Most of the decoders also allow the exporting of logs from a certain route or airport. Following the events of 9/11, information collected by planespotters helped uncover what is known as extraordinary rendition by the CIA. Information on unusual movements of rendition aircraft provided data which led first to news reports and then to a number of governmental and inter-governmental investigations.