Firefly, as at one time used by the United States Air Force Academy, and the Scottish Aviation Bulldogs of the RAF. The U.S. replaced the Firefly and the Enhanced Flight Screen Program (EFSP) with the Diamond DA20 and the Initial Flight Training (IFT) program. At the end of this stage, pilot trainees are assessed and those who pass advance to the full pilot training program. Those who are 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. The USAF Academy uses light piston-powered aircraft such as the Cirrus SR20 (designated T-53A) for basic cadet flight training. Basic training After the ab-initio phase a candidate may progress to basic, or primary, trainers. These are usually turboprop trainers, like the Pilatus PC-9 and Embraer Tucano. Modern turboprop 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's controls, reaction speed and the 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 be trained to fly multi-engined 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 supersonic Northrop T-38 Talon, the BAE Hawk, the Dassault/Dornier Alpha Jet, the Aero L-39 and the Yakovlev Yak-130. 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