Updated

Air Force officials say a series of errors led to the crash of an unmanned drone aircraft in December in a remote area north of Las Vegas.

A report released Tuesday says the pilot didn't properly execute a preflight checklist before taking control of the drone, which stalled and crashed Dec. 5 in Douglas County near Mount Irish.

Nobody was injured in the crash, but the loss of the drone and artillery on board was estimated at $9.6 million.

Nellis Air Force Base officials say the MQ-9 Reaper aircraft was being used in an Air Force weapons school combat training mission. It was assigned to the 57th Wing at the base.

A Nellis spokeswoman said it wasn't immediately clear Tuesday morning whether anyone has been disciplined for the mishap.