SAN DIEGO – A Navy air traffic controller showed "fundamental misunderstandings" of the job before a collision between a Coast Guard plane and a Marine helicopter killed nine people last year, according to a Marine Corps report released Wednesday.
The report was released one day after the Navy and Coast Guard made their findings public. All three maritime services agreed that the collision was preventable but said it was not caused by a single factor, person or misconduct but rather a general breakdown in communication.
But the Marine Corps and Coast Guard both emphasized that the Navy controller failed to follow standard air traffic control procedures, and gave higher priority to Navy F/A-18 fighter jets that were in the area.
The Marines' report said the Navy controller failed to notify the pilots even though their planes appeared on radar for 3½ minutes before the collision off the Southern California coast.
"These fundamental misunderstandings of what the controller's duty priorities ... were avoidable and led to a tragic error in judgment, directly contributing to the collision," the Marines said.
The crash occurred about 50 miles off the coast on the night of Oct. 29, 2009, when the Coast Guard plane was on a mission to rescue a boater missing for two days near San Clemente Island. The plane hit one of four Marine helicopters that were flying in formation on a training mission.
The Navy's report faulted the flight crews for failing to spot each other in the zone, which is governed by "see-and-avoid" rules, meaning pilots are on their own to watch for others even though they can request guidance from Navy controllers.
The Marine Corps agreed air traffic controllers at Naval Air Station North Island were not the only ones to blame, and that a Marine pilot should have requested radar guidance.
But "more assertive communication from air controllers to air crew is the key," the Marines' report said.
It also said the Coast Guard crew didn't fully understand flight rules in the area and that the collision could have been avoided if they used night-vision goggles. The cockpit of the Coast Guard plane was incompatible with night-vision gear, but Guard is now accelerating plans to outfit new planes with those devices.
All three services said they have taken steps to improve safety.
Coast Guard pilots now have more detailed preflight check lists that specifically address operations in warning areas. Guard pilots and Navy controllers now swap information on the airspace and the pilots' missions before they take off on their flights.
They also have implemented procedures to make clear which aircraft is given priority in the air space, said Lt. Aaron Kakiel, of Naval Air Forces at North Island Naval Air Station.
An internal review by the Navy conducted after the collision found the changes are improving coordination, Navy and Coast Guard officials said.
"We didn't wait for the reports to be finished, and we began working with the Navy to improve coordination," said Lt. Cmdr. Rick Foster, a Coast Guard spokesman.
The Marine Corps said it needs to fully consider how their formation exercises affect other services using the airspace. The Marine pilots in the collision had exceeded one nautical mile in the distance between its helicopters in formation, but the Marine Corps said all aircraft were within sight.
Foster said the Coast Guard is recommending the Federal Aviation Administration define the maximum distance between aircraft flying in a group.
The collision ignited a debate about how to best police the sky in a giant military training area off the Southern California coast — airspace that is not controlled by the FAA.