A U. S. Air Force B-52 strategic bomber that recently crashed in California had been used in tests of the new AN/APQ-188 radar with an active electronically scanned array, The War Zone reported.

According to the publication, U. S. Air Force Colonel James Hayes said the aircraft was carrying out its first takeoff under the radar modernization program.

Boeing, the aircraft’s manufacturer, confirmed to reporters that two of its employees were on board.

The War Zone reported that the U. S. Air Force still has 75 B-52 strategic bombers in service.

The crash occurred on June 15 in California. There were eight people on board the B-52, and none of them survived.