A drone crash that damaged USS Chancellorsville and injured two sailors was caused by a malfunctioning control system and human error, according to a U.S. Navy report unclassified this week.

A 13-foot, BQM-74 series unmanned drone struck the guided missile cruiser’s hull off the coast of Point Mugu as the ship was conducting training exercises on Nov. 16, causing a fire inside and minor burns to two people on board.

The redacted Navy report says equipment malfunctions were the main cause of the crash. Leading up to the strike, a target control team at Point Mugu launched the drone directly at the vessel to test its ability to defend its crew against enemy missiles.

The team then ordered the drone to turn away from the ship – a command the system ignored.

As the drone continued on its course toward USS Chancellorsville, personnel on board failed to issue a “rogue drone” alert and ignored a recommendation by the ship’s weapons system to fire on the approaching aircraft.

Pacific Fleet Commander Adm. Harry B. Harris Jr. wrote in his report that virtually everyone involved in the exercise believed the chances of a drone hitting the ship were extremely remote, so they focused on targeting and data instead of the safety concerns.

“This false confidence in the system adversely affected the time it took to both recognize and act on the problem,” Harris wrote.

He said both the Point Mugu target control team and the Chancellorsville leadership had chances to prevent the mishap and failed to do so.

Those on land knew the drone control system had failed or had performed incorrectly several times that day, yet they decided to forge ahead with the launch and did not let those on the Chancellorsville know about the problems, according to Harris’ report.

“I question this control team’s ability to continue to adequately service Pacific Fleet ships,” wrote Harris.

The admiral also decided to take administrative actions against the ship’s commanding officer, tactical action officer, anti-air warfare coordinator and combat system coordinator.

Harris rebuked the commanding officer for failing to “do everything he could and should have done; he failed to use the full range of tools available to him to protect his ship.”

Nevertheless, Harris commended the crew for their response to the fire that grew after the drone punched a 3-foot hole into the cruiser’s hull.

After the strike, USS Chancellorsville was docked at Naval Base San Diego to undergo repairs, which took about six months and $30 million, according to a Navy Times report.