May 23, 2012: A U.S. Marine Corps accident report was recently released that confirmed a rare case of bird strike bringing down a helicopter. Last September a red-tailed hawk, weighing about 1.4 kg (3 pounds), hit the top of the main rotor mast on a marine AH-1W helicopter gunship. The hawk impact damaged the pitch change link, which caused vibrations that quickly led to the transmission and rotor blades breaking away from the helicopter. The chopper then fell to earth, killing the two man crew. The AH-1 is now going to be modified to better protect the pitch change link, one of several highly vulnerable (to damage) components on a helicopter. Normally, the pitch change link would not be hit by ground fire. No one expected a bird strike up there either.
Aircraft bird strikes are a widespread, if little publicized, problem. There are about 5,000 incidents a year. These often just mean replacing windows or canopies, or wherever the bird hit. Most of the incidents involve near misses or collisions on non-critical portions of the aircraft. But in about one percent of the incidents the damage is severe and some aircraft are lost. On average, 40-50 people a year die because of aircraft bird strikes.
Nearly all the fatal bird strikes are to aircraft with gas turbine engines (which birds fly into). This often wrecks, or severely damages, the engine when the high speed fan is damaged. Multiple engine aircraft usually can survive this if they still have one or more working engines. But sometimes single or two engine aircraft lose all engine power and go down. One exception was the "Miracle On The Hudson" in January 2009, when an Airbus 320 over New York City lost both engines to bird strikes. Exceptional work by the crew managed to bring the aircraft down, intact, on the Hudson River.