A trainer is a class of aircraft designed specifically to facilitate in-flight training of pilots and aircrews. The use of a dedicated trainer aircraft with additional safety features—such as tandem flight controls, forgiving flight characteristics and a simplified cockpit arrangement—allows pilots-in-training to safely advance their real-time piloting, navigation and/or warfighting skills without the danger of overextending their abilities alone in a fully featured aircraft.
Civilian pilots are normally trained in a light aircraft, with two or more seats to allow for student and instructor. The aircraft may be modified to withstand the flight conditions imposed by training flights.
Tandem or side by side
The two seating configurations for trainer aircraft are pilot and instructor side by side or in tandem, usually with the pilot in front and the instructor behind. The side-by-side seating configuration has the advantage that pilot and instructor can see each others actions, allowing the pilot to learn from the instructor and the instructor to correct the student pilot. The tandem configuration has the advantage of being closer to the normal working environment that a fast jet pilot is likely to encounter.
It is now the norm for pilots to begin their flight training in an aircraft with side by side seating and to progress to aircraft with tandem seating. This however has not always been the case. For example, it was usual to find tandem seating in biplane basic trainers such as the Tiger Moth and the Jungmann, and the British used side by side seating in the operational conversion of some of its fast jets such as the English Electric Lightning.
Phases
Given the expense of military pilot training, air forces typically conduct training in phases to winnow out unsuitable candidates. The cost to those airforces that do not follow a gradated training regimen is not just monetary but also in lives. For example, for many years the Indian Air Force operated without a suitable advanced training aircraft, leading to a high casualty rate as pilots moved to high performance MiG 21 aircraft without suitable assessment of their aptitude for supersonic flight. In times of war the chances of victory increase with the quality of a pilot's training.There are two main areas for instruction, flight training and operational training. In flight training a candidate seeks to develop their flying skills. In operational training the candidate learns to use his or her flying skills through simulated combat, attack and fighter techniques.
Ab initio
Typically, contemporary military pilots learn initial flying skills in a light aircraft not too dissimilar from civilian training aircraft. In this phase pilot candidates are screened for mental and physical attributes. Aircraft used for this purpose include the Slingsly Firefly, as at one time used by the USAF Academy, and the Scottish Aviation Bulldogs of the RAF. The USAF replaced the Firefly and the Enhanced Flight Screen Program (EFSP) with the Diamond DA20 and the Initial Flight Screening (IFS) program At the end of this stage pilot trainees are assessed as to where their attributes lie, as fast jet, multi-engine or rotary wing pilots. Those judged unsuitable for a pilot commission, but show other attributes may be offered the chance to qualify as navigators and weapons officers.Smaller and more financially restricted air forces may use ultra-light aircraft, gliders and motor gliders for this role.
Basic training
After the ab-inito phase a candidate may progress to basic trainers/primary trainers. These are usually turboprop trainers like the Pilatus PC-9 and Embraer Tucano. Modern turbo-prop trainers can replicate the handling characteristics of jet aircraft as well as having sufficient performance to assess a candidate's technical ability at an aircraft controls, reaction speed and ability to anticipate events. Prior to the availability of high performance turboprops, basic training was conducted with jet aircraft such as the BAC Jet Provost, T-37 Tweet, and Fouga Magister. Those candidates who are not suitable to continue training as fast jet pilots may be offered flying commissions and train to fly multi-engined aircraft e.g. transport and tanker aircraft.
Advanced training
Those that progress to training for fast jet flying will then progress to an advanced trainer, typically capable of high subsonic speeds, high-energy manoeuvers, and equipped with systems that simulate modern weapons and surveillance Examples of such jet trainer aircraft include the T-38 Talon (actually capable of supersonic speeds), the BAE Hawk, the Dassault/Dornier Alpha Jet, the Aero L-39 and the FMA IA 63 Pampa.Effective combat aircraft are a function now of electronics as much as if not more so than the aerobatic ability or speed of an aircraft. It is at this stage that a pilot begins to learn to operate radar systems and electronics. Modern advanced trainers feature programmable multi-function displays which can be programmed to simulate different electronic systems and scenarios. Most advanced trainers do not have radar systems of their own, but onboard systems can be programmed to simulate radar contacts. With datalinks and GPS virtual radar systems can be created with similarly equipped aircraft relaying to each other their positions in real time and onboard computers creating a "Radar display" based on this information.The aim of programmable displays is to speed pilot training by replicating as far as possible the systems a pilot will find in an operational aircraft.