TAIPEI (Taiwan News) — The F-5E is the only type of jet still not allowed to fly following thorough checks after a fatal mid-air collision on March 22, the Air Force said Tuesday (April 6).

One pilot was killed and one disappeared after two F-5E jets collided and crashed into the sea off Pingtung County during a routine training mission. The incident led to the grounding of all fighter jets and to calls for the replacement of ejection seats, which reportedly played a role in the death of one officer.

Following a two-week general review, the Air Force allowed flights to resume on March 30 for its U.S.-built F-16s, French-built Mirage 2000-5s, and Indigenous Defense Fighters (IDF), as well as for its C-130H transport planes and P-3C Orion anti-submarine aircraft, CNA reported.

The twin-seat F-5F fighter jet received the green light for test flights on Tuesday, with two of the planes making a 40-minute morning test flight out of a base in Taitung County.

The results of the test flights could influence the decision of when to resume operations for the single-seat F-5E, the type of jet involved in last month’s crash.

Taiwan’s Air Force has been busy over the past year warding off almost daily incursions by Chinese military planes into the country’s air defense identification zone (ADIZ).