Ten people were injured, including seven transported to the hospital, when an Osprey military aircraft performing a Memorial Day demonstration in a Staten Island, New York, park knocked down tree limbs onto spectators.
The Osprey MV-22 aircraft was landing at Staten Island's, Clove Lakes Park around 9 a.m. Monday as part of Fleet Week when it blew down a number of tree limbs. Video captured by an overhead chopper filming the demonstration shows spectators scrambling for cover as the powerful helicopter - which combines airplane-like wings with rotors that let it take off and land vertically, like a helicopter -- kicked up a terrible wind.
"It was like two tornadoes with the propellers," eyewitness Keith Carlsen told NBCNewYork. "They got low and everything started flying. I was walking 300 yards away and it was still amazing."
Onlookers first scrambled for cover and then rushed to clear fallen branches to see if people were trapped beneath them. Parents snatched up small children and carried them out of harm's way. One tree lost all its branches on one side, photographs from the scene show.
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"The wind was unbearable," recalled eyewitness Anita Muriale. "People were falling. Trash was going all over the place. Trees was flipping -- I ran!"
Ten people suffered minor injuries in the mishap. Seven people taken to Richmond University Hospital and three people on the scene refused treatment, according to the fire department.
The MV-22 is a Marine Corps version of the V-22, which combines airplane-like wings with rotors that let it take off and land vertically. It "stirs up a lot of wind, and that's apparently what did it," Marine Corps spokesman Lt. Josh Diddams said.
"We came in over the trees and the next thing I see is a Tennessee Titans blanket blowing up in the air and so that made me think something was below us," Capt. Mike Henson told NBCNewYork. "And I turned down and looked and there's some people walking away from the downed tree."
A joint venture of Boeing Co. and Fort Worth-based Textron Inc.'s Bell Helicopter, the V-22 is designed to carry 24 combat troops and fly twice as fast as the Vietnam War-era assault helicopters it was designed to replace.
The Osprey program was nearly scrapped after a history of mechanical failures and two test crashes that killed 23 Marines in 2000. But development continued, and the aircraft have been deployed to Iraq.
While the General Accounting Office questioned the V-22's performance in a report last year, the Marine Corps has called it effective.
In hindsight things would be done differently but every precaution had been taken, the Marine regiment commander in charge of the operation said.
"All I can tell you is we hit all of the safety parameters as far as distances," Col. Eric Smith said. "So the people were as far back as they should have safely been. But that tree limb obviously was not something we anticipated snapping."