An Air Force instructor pilot with the 80th Flying Training Wing at Sheppard Air Force Base, Texas died overnight from injuries sustained when their T-6A Texan II ejection seat activated during ground operations here May 13, the Air Force said in a release.

Capt. John Robertson of the 80th Operations Support Squadron was severely injured when the ejection seat of the T-6A Texan II aircraft he was in activated during ground operations Monday, the Air Force said. He died of his injuries overnight.

“This is a devastating loss for Captain Robertson’s family and loved ones, and for the entire 80th Flying Training Wing,” said Col. Mitchell J. Cok, the acting wing commander. “Captain Robertson was a highly valued Airman and instructor pilot. Our deepest condolences go with all who knew and loved him.”

The T-6A is a propeller-driven trainer that is the first plane student pilots officially are taught to fly at Undergraduate Pilot Training, or UPT. All Air Force pilots, regardless of the plane they will eventually fly, begin their flight training at UPT at Sheppard of another training base.

The mishap is the latest in a series of issues with the T-6A’s ejection seats. The Air Force grounded over 70 T-6s, alo in 2022 after defective explosive cartridges were found in the seats.

“We are thankful for the M1 maintenance team who immediately provided live-sustaining care, and for the heroic efforts of the security forces, fire and medical personnel here on base and at United Regional Hospital. Their efforts allowed time for Captain Robertson’s family to be at his side when he passed,” Cok said.

Sheppard is among the busiest Air Force bases in the world, launching 250 flights each day for UPT training and a follow-on course, Introduction to Fighter Fundamentals. IFF is the qualifying course for future pilots of fighter jets and other high-performance aircraft. Students fly the T-38 in that course.

Sheppard also hosts flight training for 14 NATO countries through the Joint Jet Pilot Training Program.

Sheppard is in north Texas adjacent to the city of Wichita Falls on the Oklahoma state border.

An investigation into the cause of the incident is underway. Per Air Force policy, the pilot’s name is being withheld until 24 hours after the notification of next of kin.