A United States Air Force Boeing B-52 Stratofortress strategic bomber crashed and burst into flames shortly after takeoff from Edwards Air Force Base in southern California on June 15, killing all eight crew members on board in the deadliest crash of a B-52 since 1982.

The aircraft was on a routine test flight for a radar modernization program. The crew included active military personnel, government civilians and contractors. The Air Force confirmed all eight were killed in the crash, which occurred in the desert terrain near the base. The wreckage site was secured and personnel from nearby communities were not affected.

Early flight data showed the bomber plunged at nearly a mile per minute before impact, according to PBS NewsHour reporting on the investigation’s initial findings. The Air Force paused flight test operations at Edwards following the crash while investigators assessed the aircraft and gathered evidence. The full investigation is expected to take up to six months, according to the Air Force’s statement.

Investigators are examining engine performance, controllability during takeoff, and maintenance records. The widow of one of the crew members told local outlet KTLA that the plane had experienced issues the Friday before the fatal flight, causing a delay — a detail that investigators will examine as part of their review of whether the aircraft should have flown on June 15. The Air Force identified all eight crew members by name, though a full public identification was made in stages out of respect for the notification of next-of-kin.

The B-52 Stratofortress has been in continuous service with the US Air Force since 1955, making it one of the longest-serving military aircraft in history. Edwards Air Force Base in California’s Mojave Desert is the primary flight test centre for the US military, handling developmental and evaluation flying for new and upgraded aircraft across all services. The Al Jazeera report has the full crew identification and investigation timeline. For other major US incidents this week, the Texas highway plane crash killed Capital Factory CEO Joshua Baer and the FBI disrupted a drone plot targeting the White House UFC event.

Eight crew members went up for a test flight and did not come back. The investigation will determine why. The answers, when they come, will matter for the future of an aircraft the Air Force plans to fly well into the 2050s.