The US Air Force has launched an investigation into the cause of the first major accident to have involved a Boeing C-17 strategic transport.
A C-17A assigned to the service's 3rd Wing at Elmendorf AFB, Alaska crashed on the base at 18:14 local time yesterday while "on a local training mission", the service confirms.
The status of the four crew members aboard the aircraft was listed as "unknown" following the incident.
© Senior Airman Laura Turner/USAF
According to local media reports, the C-17's crew had been rehearsing a display routine for the Arctic Thunder air show, which is scheduled to be held at Elmendorf on 31 July and 1 August.
The USAF's C-17A fleet totalled 199 aircraft before the 28 July accident, says Flightglobal's MiliCAS database. Another 19 of the type are also operated by the air forces of Australia, Canada, Qatar and the UK, and by a 12-nation consortium of NATO and Partnership for Peace nations.