The Air Force has identified the eight crew members who were killed in a B-52 crash at California’s Edwards Air Force Base on Monday. The victims included military personnel, contractors, and government civilians.

Those killed were identified as 40-year-old Lt. Col. Gabriel Estrella, a weapons systems officer; 34-year-old Maj. Alexander Davis, a weapons systems officer; 40-year-old Maj. Robert Dee, a pilot with the 419th Test Squadron; and 35-year-old Maj. Brad Hovey, also a 419th Test Squadron pilot. The list also included 32-year-old Jeromy Smith, a flight test engineer; 41-year-old Christopher Rischar, a contractor and flight test engineer; 50-year-old retired Lt. Col. Miles Middleton, who served as a Boeing pilot; and 53-year-old Col. Gregory Watson, a Boeing weapons officer and Air Force reservist.

In a news release identifying the victims, Col. Thomas Tauer, 412th Test Wing commander, said that “They were dedicated professionals, beloved family members and irreplaceable teammates. … These Airmen were more than coworkers. They were friends, mentors, teammates and valued members of our Edwards and Air Force family.” 

The crash occurred around 11:20 am on Monday at Edwards Air Force Base in Kern County, California. The crew was reportedly conducting a routine test mission in support of the Air Force’s modernization program of the B-52 fleet. 

An investigation will examine the aircraft’s takeoff and potential engine failures or control issues. Additionally, an investigation will examine maintenance records, particularly after a report by KTLA that Smith’s widow had said the plane was experiencing issues on Friday prior to the crash. An Air Force investigation could take up to six months to complete.