The US Representative Martha McSally has amended defence funding legislation to provide $100m for new A-10 wing upgrades.

The fiscal year 2016 Defense Appropriations Act was passed by the US House of Representatives, preventing the retirement of any A-10s.

The bill also covers full funding for EC-130H airborne tactical weapon system.

The amendment comes as more than 100 A-10 aircraft are required to be upgraded with re-fitted wings to extend their service period beyond 2028.

McSally said that 110 of the 283 remaining A-10s in the US Air Force's (USAF) inventory have not received funding for the required wing upgrades.

Without the proposed upgrades, 13 A-10s would begin to be grounded in FY2018, 28 by FY2019, and nearly 50 by FY2021.

McSally further added: "This amendment sends another strong signal that Congress backs the A-10 and supports keeping them flying.

"We've mothballed the equivalent of four A-10 squadrons over recent years, leaving us with barely enough aircraft to meet current threats."

"We've mothballed the equivalent of four A-10 squadrons over recent years, leaving us with barely enough aircraft to meet current threats.

"With A-10s deployed to four theatres around the world, we not only need to prevent the premature retiring of anymore A-10s, but we need to ensure the aircraft we have are able to continue flying until a tested, proven replacement is developed and that's what this amendment does."

Earlier this year, the US Government announced plans to begin divestment of its entire A-10 fleet and seven of the 15 EC-130H at Davis-Monthan Air Force Base, which houses more than 80 A-10 Warthogs and 15 EC-130H Compass Call aircraft.

The A-10 Thunderbolt, also known as the Warthog, is designed to conduct ground attack against tanks, armoured vehicles and installations, and close air support of ground forces.

Image: A fully armed A-10 aircraft in flight. Photo: courtesy of US Air Force photo by Master Sgt. Blake R. Borsic.