BAE Systems has finished testing the fuel gauging systems of the first F-35 Lightning II short take-off and vertical landing (STOVL) aircraft.

The aircraft, also known as the joint strike fighter (JSF), was tested constantly for 13 days at Lockheed Martin’s Fort Worth plant in Texas.

A BAE Systems spokesperson said: ‘It was a milestone moment in the programme. This is the first STOVL we’ve tested, and we wanted to make sure the designs worked and check that the fuel systems had been put together properly.’

BAE Systems will now carry out structural coupling, ground vibration testing and complete hydraulic testing of the doors and landing gear.

Three versions of the F-35 aircraft are planned, so in addition to the STOVL there will be a conventional take-off and landing (CTOL) and a carrier variant (CV).

The F-35 is said to be the first and only stealthy, supersonic, multirole fighter, and is being developed for the US Air Force, Navy and Marine Corps to replace the AV-8B Harrier, A-10, F-16 and the F/A-18 Hornet. In the UK, the aircraft will replace the Royal Air Force’s and Royal Navy’s Harrier GR.7 and Sea Harrier.