Lockheed Martin has begun flight testing of block 1 software for all variants of the F-35 Lightning II stealth fighter.

The maiden flight of block 1 software was conducted in the F-35B short take-off / vertical landing (STOVL) aircraft known as BF-4.

The block 1 software will enable most of the primary sensors on the F-35, which possesses the most powerful and comprehensive mission systems package to fly.

The software will enable information fusion from the F-35’s radar, electronic warfare system, distributed aperture system and electro-optical targeting system, and provide initial weapons-release capability.

Block 1 has already undergone airborne tests on the cooperative avionics test bed, a highly modified 737 airliner.