Wind, Load Oscillation Contributed To The Accident, Report Indicates

A report released by the U.S. Marine Corps indicates that civilian contractors employed by Lockheed Martin remotely piloting a K-Max unmanned helicopter in Afghanistan June 5, 2013 lost control of the aircraft because it had been programmed to anticipate a 15 mph headwind at its dropoff point, and encountered a tailwind instead.

The report, which was obtained by The Washington Post through the Freedom of Information Act, indicates that the operators had tried to employ a "weathervane" maneuver to bring the aircraft into the wind, but the 2,000 pound load began to swing underneath the aircraft and caused it to go down. The $11.1 million aircraft was destroyed by the impact. A laptop computer collecting data about the flight was ejected from the aircraft on impact and was recovered.

The investigators said that the accident was "preventable" and that the primary factor was the slow reaction by the operators to the unexpected wind. The investigators also said that the personnel on the ground should have provided updated weather information to the remote crew. According to the report, “the aircraft could not recover on its own based on the diverging conditions and its insufficient programming; it required human intervention."

The investigators have recommended improved communications between personnel on the ground and remote piloting crews, according to the report. They also recommend additional training to deal with swinging or oscillating loads suspended beneath unmanned aircraft.

Lockheed told the Washington Post that it has already addressed the concerns raised in the Marine Corps' report.

(Image from Marine Corps documents showing forecast and actual wind conditions at the time of the accident)

FMI: www.marines.mil