TAIPEI (Taiwan News) — Photos from an online American aviation page reveal the first public sighting of Taiwan’s F-16V Block 70 fighter jets undergoing ground testing in the US.

Taiwan has purchased 66 of the jets from the US, and Lockheed Martin held a rollout ceremony for the first aircraft, tail number 6831, in March, per CNA. Then–Deputy Defense Minister Po Hung-hui (柏鴻輝) and Taiwan’s US representative Alexander Yui (俞大㵢) attended the event.

Early Saturday morning, the US aviation photography Facebook page Owen’s Aviation Photos posted images of a two-seat version with the tail number 6831, conducting ground taxi tests at Donaldson Field Airport, captioned “First sighting of the Taiwan F-16 Block 70!” Another photo showed the test pilot wearing a helmet-mounted targeting system.

Shu Hsiao-huang (舒孝煌), an associate research fellow at the Institute for National Defense and Security Research, told CNA that the photos indicate the aircraft has been fitted for conformal fuel tanks. These extend the F-16V’s flight endurance and free up underwing hardpoints previously used for external fuel tanks to carry additional weapons.

Shu added that the new fighter is equipped with multiple new electronic warfare systems that must undergo ground testing before flight to ensure the systems do not interfere with one another. Only after these tests are completed will the aircraft proceed to flight testing and then full systems evaluation.