EGLIN AIR FORCE BASE, Fla. - The dreaded fuel light, either blinking or glowing red indicating low on gas, becomes a constant reminder that a stoppage of the drive, trip or mission is imminent. The A-10 section of the 40th Flight Test Squadron is testing the expansion of the Thunderbolt II's fuel capability to prolong its flight time, remain in the fight and keep that fuel light off a while longer.
In 2012, Air Combat Command requested testing, via the Air Force Seek Eagle Office here, to possibly expand the A-10 carriage limits of its 600-gallon fuel tank with all existing fuel tank configurations such as various weapon loads.
"Currently, the A-10 doesn't carry an external fuel store into combat," said Maj. Olivia Elliott, the test pilot for the expansion. "The present flight limitations on the Sargent Fletcher tank restrict it from being flown in a combat environment."
Flight testing was accomplished on the SF tank in 1997, but it was never evaluated for combat requirements. The goal for the 40th FTS team was to determine if the aircraft could safely reach those combat flight limits carrying the tank, thus carrying more fuel into battle.
"By expanding the fuel carriage limits, A-10C units can carry the 600-gallon tank into combat expanding loiter time by 45-60 minutes and pushing back tanker support," said Elliott. "This will allow the aircraft to remain in flight during a combat situation longer, provide lengthier periods of armed over-watch for ground missions, as well as limit the amount of time spent air-to-air refueling during a combat sortie."
In more than 30 missions, the tank was pushed to greater airspeeds, Mach levels and higher symmetrical (pulling Gs without rolling) and asymmetrical (rolling and pulling Gs) limits to simulate a possible combat setting.
At first, missions focused on gathering data to set the baseline for the aircraft's handling characteristics. Then other missions focused on different aircraft load configurations to ensure sound flight capability.
"The scenarios were engineered to check a variety of weapons on the A-10 and clear the tank to the expanded limits with most combat weapons loaded on the aircraft," said Capt. Rojas, of the 40th FTS.
There have been no anomalies seen to date in the testing, according to Elliott.
"The flying qualities of the aircraft show slightly reduced stability in the yaw axis; but during handling quality evaluations, there has been no decrease in aircraft tracking performance," she said.
With only a few missions left to fly, the test team will begin the report write-up. The 40th passes on their findings to Seek Eagle. AFSEO will determine if a flight clearance can be issued. If it is, the Air Force Special Projects Office will update the A-10s flight clearance to include the expanded tank limits and the tank will be able to be used in combat.