Washington The Marine Corps has taken disciplinary action against the pilot and co-pilot of an MV-22 Osprey aircraft that was flying a short distance ahead of the Osprey which crashed in the Arizona desert in April, killing 19 Marines, a senior Marine general said Thursday.
Lt. Gen. Fred McCorkle, the head of Marine aviation, told a Pentagon news conference that an internal review board concluded that the two pilots of the lead Osprey were partly responsible for the accident because they failed to follow the flight plan and put themselves in a position of having to descend too rapidly.
The decision by the pilots of the first aircraft to continue their approach to the Marana airport -- instead of pulling up and trying a new, safer approach -- despite an excessive rate of descent "resulted in the mishap aircraft chasing (the lead aircraft) into the (landing) area," a summary of the accident investigation report said.
The crews of neither Osprey "recognized the dangerous potential of the flight profile," the summary said.
McCorkle said the two pilots will not be allowed to fly as aircraft commanders of any Marine Corps aircraft for six months, and after that period they will be required to requalify for that designation. He did not identify the pilots and said details of the disciplinary action are "privileged information."
The investigation report summary released by McCorkle said that although the crew of the Osprey which crashed made mistakes and misjudgments, the main cause of the accident was "human factors," not pilot error.
Asked to explain the difference, McCorkle said the pilot and co-pilot of both aircraft had committed "human factor errors."
McCorkle said it appears in retrospect that the pilots should have broken off their approaches to the airport and circled for another landing attempt. As to why they did not, he said he could only speculate that, "as Marines, they were trying to complete the mission."
The Osprey is unique in its ability to take off like a helicopter, rotate its propellers 95 degrees and fly like an airplane. A group of four Ospreys were participating in a mock "noncombatant evacuation" exercise at Marana, about 30 miles northwest of Tucson, when the accident occurred.
The too-rapid approach of the second Osprey produced a phenomenon known as "vortex ring state" -- essentially a stall, the investigators concluded. The Osprey plunged into a fatal nose dive, killing the crew of four and their 15 passengers.
The crash was the worst aviation disaster for the Marines since 22 were killed in a helicopter crash in South Korea in 1989.
The Marine Corps halted flights of its remaining Ospreys after the April 8 accident, then resumed flying in early June.
The Marine Corps had previously announced that investigators found no evidence of mechanical, engineering or structural flaws in the Osprey. The final report released Thursday affirmed that finding.
The Osprey that crashed was piloted by Maj. John Brow, considered one of the Marines' most skilled pilots.
Brow brought the Osprey into its approach to Marana airport at more than 2,000 feet per minute -- far in excess of the plane's maximum safe descent rate of 800 feet per minute, the report said.
Because of the rapid rate of descent and a slow forward air speed, the Osprey lost lift. It was less than 300 feet off the ground when it flipped to the right and plunged nose first into the ground.
The manufacturers -- Boeing Co. and Bell Helicopter Textron -- are due to deliver 11 Ospreys to the Marines this year. Eventually the Marines are to field 360 of them to replace the corps' Vietnam-era CH-46 helicopters as the primary means of transporting troops into combat from ships offshore.
The Air Force plans to buy 50 Ospreys.