AT-3 Advanced Jet Trainer

The AT-3 is designed to reflect the advanced training concept and to provide the most effective training at the lowest cost for both the initial acquisition and operational life of the aircraft. The first flight of the AT-3 took place on September 16, 1980, and the production started in March 1982. With its proven record in service, the AT-3 is well-known for its outstanding performance in maneuverability, reliability, and low operating cost. It is exceptionally well suited for advanced fighter pilot training as well as ground attack missions.

The Thunder Tiger Aerobatics Team is not only the representation of the excellent fighting skills of the Air Force, but also the communication bridge between the Taiwanese citizens and the Air Force itself. On August 14th, the Air Force Day every year, people come to the Air Force Base with their families under the blazing sun just for seeing the wonderful airshow of the Thunder Tigers and enjoying the spectacular aerobatics with the AT-3 jet trainer.

Before the 1980s, T-33 was the only type of advanced trainer in Air Force Academy. However, in view of the long service and outdated functions of T-33, Aero Industry Development Center (AIDC) decided to replace it by developing a new type of advanced trainer. Evaluation of the plan was submitted for the first time in March 1975 with the U.S. Northrop Aircraft Inc. selected as a cooperation partner.

Northrop Aircraft Inc. had once cooperated with our country for the F-5E/F fighter jet. At that time, they were also planning to design a new type of trainer called VTXTS for the U.S. Navy. A primary plan thus began in 1976, which marked the beginning of AT-3. The formal cooperation had been proceeding smoothly for ten months; however, the U.S. Government unexpectedly denied the cooperation project, which terminated cooperation with Northrop.

Due to the urgent demand for a new type of trainer, AIDC decided to research and develop AT-3 by itself. With the experience and technical information from the U.S., and the efforts of the members in AIDC, the first experimental XAT-3 (No. 69-6001) was manufactured at 10 a.m., July 17th, 1980 and completed a test flight in the same year, which symbolized our great progress in the aerospace industry. The test results of XAT-3 were found to meet all the requirements. The military authorities thus decided to purchase fifty AT-3s as advanced trainers for the Air Force Academy.

Stepping into mass production in 1984, AT-3 was forwarded to the Air Force Academy directly while T-34C was still taken as the basic trainer. Till the present day, both types of aircraft still serve as the basic trainer and the advanced trainer in the Air Force Academy.The body and wings of AT-3 are mainly made of light alloy. In addition to steel and magnesium alloy, the ultra-light graphite-fiber composites are also used to make the aircraft body much lighter and to effectively upgrade the locomotion and missile load.

The fabrication of AT-3 can be divided into three parts. First, the nose part with the cockpit. Second, the body part with the engine module. Third, the tail part with the vertical and horizontal stabilizers. The horizontal stabilizer is single-plated and fully-mobile. A single-wheeled tripod landing gear and a wheel spacer with the same two-step lengthening device as F-5E can effectively reduce the distance required to take off. The cockpit of AT-3 comprises two seats in tandem and a canopy that opens rightward. The back seats are higher than the front seats by 30 cm. In fact, the former AT-3 was equipped with two independent canopies, but such design tends to block the pilot's view. Therefore, a combined canopy is applied in AT-3 after No. 0815. As for the ejection seat, a Martin Baker MK. 10L is adopted.

AT-3 is equipped with two fuel systems, which are independent and capable of cross-feeding. As one fuel system is damaged or down, the other will automatically replace the former and provide fuel for both engines. Moreover, the fuel tank is featured by the leak-proof and auto-sealing devices. The capacity of each is 815 liters (215 gallons), which is 1630 liters for the two in total. In addition to the main tanks, two external fuel tanks of 568 liters can be hung under the two wings, effectively extending the continuous flight time.

Researched and developed in cooperation with U.S. Garrett Aviation Services, the TFE731-2-2L turbofan engine used in AT-3 has been manufactured by the 2nd Chieh-Shou Plant since 1984, mainly comprising a 1st class fan, a 4th class axial low-pressure compressor, a 1st class centrifugal high-pressure compressor, a counterflow combustion chamber, a 1st class high-pressure turbine and a 3rd class low-pressure turbine, which is able to produce the compression ratio of 14: 1, and the bypass ratio is about 2.7: 1. The maximum thrust of TFE731-2-2L is 1587 kg, and 344 kg in normal cruise (0.8 Mach, 12200 m). The thrust ratio is about 0.61.

The avionics system of AT-3 is mainly manufactured by the 3rd Chieh-Shou Plant, which was established on April 1st, 1980. Most of the avionics system, such as communication or navigation equipment, mainly lies in the nose part of the aircraft, including the Ultra-High Frequency (UHF), Identification Friend or Foe (IFF), the Tactical Air Navigation System (TACAN), the Attitude and Heading Reference System (AHRS), and an Angel of Attack Indicator.

AT-3 is also equipped with the Head-Up Display (HUD), which may not be classified as advanced equipment nowadays; however, it was one of the best if compared with other trainers at that time. The avionics systems include a radar display, Doppler Radar, FLIR, the Inertial Navigation System, a Radar Warning Receiver, and disturbing pieces, which can be used to meet the requirements of different combats.

The weapon load of AT-3 is 2727kg with a total of seven storage racks - four under the two wings, one under the belly, and two at the wingtips. The load capacity of the belly rack is 910kg, capable to carry a High Explosive weighing 907 kg or an AN-M312.7 machine gun bag. The two inner racks under the wings can carry 636kg, including bombs or incendiaries of 227kg and an external fuel tank of 568 liters. The two outer racks can load 272kg, which is about the weight of 19 rocket pods. The racks at the wingtips can hold AIM9 infrared-guided Sidewinders or Tien-Chien I air-to-air short-range missiles.

The jet has been involved in 13 crashes through 2014, with the ROC Air Force’s precision flying team, the Thunder Tigers, losing seven officers in six of those crashes. In the face of criticism that the jet is becoming a ‘flying coffin’ too dangerous to take aloft, especially for tight maneuvers like the Thunder Tigers’ shows, the Air Force announced in October 2014 that it would soon be phasing the aircraft out of service.

The Ministry of Defense has not made a decision yet on whether to produce a replacement for the AT-3 in Taiwan or to purchase aircraft from overseas. Local manufacturer Aerospace Industry Development Corporation (AIDC) produced the indigenously-developed IDF fighter, and jet trainers do not present a particularly high technical threshold. It would be a fairly simple matter to produce a homegrown model in cooperation with foreign manufacturers to replace the aging AT-3.

The Air Force had already begun the search for a new aircraft to replace the AT-3 trainer, which was first introduced in 1984 and had thus completed a full 30 years of service. An extension program carried out by AIDC extended the model’s lifetime until 2016, and the Air Force hopes to bring in a suitable replacement by that time.