GG1001

In the face of increased USAF hostility to the F-20, the aircraft was given the civilian registration N4416T. It was repainted yet again the silivery 'BMW grey' scheme after the rollout of GI1002 in May 1984 and prior to departing for the Farnborough Air Show in August 1984.

GG1001 began flight test in August 1982, and had logged 240 flights by end of April 1983, including evaluation flights by 15 pilots from 10 potential customer nations. First 100 flights at rate of 10 per week, with a maximum of six sorties in one day and 14 sorties in a single week. During the period, only 4 of 244 departures were canceled, a mission reliability rate of 98.3%. Causes for the aborts were a hydraulic leak in a landing gear strut, a leaking aileron actuator seal, a control and augmentation system built-in test equipment failure, and a faulty roll gyro.

The aircraft flew 51 sorties in the first 21 days with a reliability rate of 100%, including 22 consecutive flights with no maintenance discrepancies. The goal of the early testing was to clear the flight envelope sufficiently to allow customer pilots to fly the aircraft. Even with the 16,000-lb thrust test engine, climb and acceleration were better than predicted, and fuel endurance was significantly better than predicted.

Longest flight on internal fuel was 2 hours 12 minutes, and 3 hours 1 minutes with a 275 gallon external tank. Handling has been excellent with the longitudinal flight control system. Mindful of having reversed its tradition of building only twin-engine aircraft for safety reasons, Northrop was striving to make the F404-100 engine have an in-flight shut-down / failure rate one tenth that of the F404-400 used in the twin-engine F-18.

The test engine had to removed once for foreign object damage after 178 flights and 115 flight hours. The engine was replaced, then repaired and available as a spare within a few days. The first 17,000 lb thrust engine was installed in GG1001 after return from the Paris Air Show.

August 1978 - First Northrop Risk Work Authorization approved.

This extended the handling of design changes on GG1001, 1002, 1003, 1004 to ensure the most efficient incorporation of changes.

This redirected the GG1004 subprogram and resolved the difficult schedule conditions imposed by the multiple uses planned for the aircraft. Instead it would just be completed as the first F-5G-2.

This Program Directive established the requirements for a functional fixture in support of program criteria published in Program Directive 17. It directed that manufacturing material resources be minimized as much as possible while supporting functional fixture requirements.

This was issued to clarify activities scheduled for aircraft GG1001, which include participation in the 1983 Paris Air Show, spin susceptibility tests, and refurbishment for sale in the F-5G-2 configuration.

By this time a management directive had come down to stop referring to the aircraft as the F-5G, but rather only the "Tigershark".

This was issued to provide configuration definition of the F-20A operational display at the Paris Air Show of 1983.

The aircraft were accompanied by the corporate Gulfstream business aircraft. The Gulfstream carried marketing staff, five maintenance technicians, and a few spare parts. This five-man technical team and the spares carried supported both F-20 aircraft for the entire 76-day, 29,455 nautical mile journey. Both aircraft completed the 6,000 mile flight to from Edwards AFB to Farnborough, England, without a single aircraft system failure.

Performance of GI1001's radar was noticeably degraded in the hot, humid, dense air of the Persian Gulf.

It can be speculated that Indian Air Force personnel were given an unofficial look at the aircraft.

The aircraft were grounded for two days by monsoon rains. The aircraft were parked outside and moisture intruded into one compartment. When a borrowed airline power unit was used to power up the aircraft, an overvoltage damaged the components in the compartment. Northrop noted that production aircraft would have a sealed avionics compartment. Spare components were swapped from the limited inventory in the aircraft and the team took off with a 2.5 hour delay.

After the demonstration the F-20's were fitted with three external tanks each for the direct flight to Korea.

A nonstop flight from the Philippines to Korea was planned, but one F-20 could not transfer fuel from the right internal tank, so an unscheduled stop was made on Okinawa to refuel that aircraft. It was found that a fuel-tank check valve had been improperly installed. The team still arrived in Korea only 30 minutes behind schedule.

GG1001 crashed at Suwon Air Base in South Korea during a tactical performance demonstration. Northrop Chief Test Pilot Darrell E Cornell was killed. Cornell had just completed a simulated strafing run at an altitude of about 300 feet when he pulled the aircraft up to an altitude of 1500 to 2000 feet, began a roll, and extended the landing gear and flaps. The roll was not completed and the aircraft continued inverted in an arc and struck the ground. The turn-in pull-up over the runway, and 360-degree aileron roll during which the landing gear was extended, had been part of the standard F-20 flight demonstration performed by Cornell at air shows on the nearly-completed F-20 world tour. The maneuver usually ended with the aircraft about 1,000 feet near the downwind end of the runway from which a base leg was entered for landing.

Cornell was thrown clear from the aircraft on impact. The demonstration was being performed before South Korean military officials, including the Chief of Staff of the Korean Air Force. GG1001 and GI1002 had arrived in South Korea on October 8, the last stop in a series of visits to 19 countries. The two aircraft were to have returned to Edwards Air Force Base on October 12.