Israel's air force will take delivery of an additional Lockheed Martin F-35 in 2020 with a special suite of test instrumentation.

"This unique aircraft, which was not part of any other F-35 contract, will enable us to begin the work of upgrading the capabilities of this aircraft so that it answers our special operational requirements," says the commander of the air force's test centre, identified only as Lt Col Shlomy.

The unique test aircraft is being manufactured according to specifications that took two years to prepare, he adds. It will be used to enhance the type's capabilities during air-to-air and air-to-ground missions.

"All our platforms have been upgraded to enable stretching the flight envelope while using the unique weapon systems made by Israeli industry," Shlomy says.

Planned updates to Israel's operational F-35I "Adir" fighters will be "directly connected" to the type's scheduled maintenance programme, "in order to not disrupt the aim of the shortest time on the ground between complex missions".