RAF MILDENHALL, England — A series of bird strikes that knocked the pilot and co-pilot unconscious caused a U.S. HH-60G Pave Hawk helicopter to crash at a nature preserve in England earlier this year, the Air Force said in a report released Wednesday.
The crash occurred in January on the Cley Marshes, a nature preserve near Salthouse, England, while two helicopters from the 56th Rescue Squadron out of RAF Lakenheath were conducting a low-flying training exercise to rescue a downed F-16 pilot. The crash killed the pilots and crew of the trailing helicopter: Capt. Christopher S. Stover, Capt. Sean M. Ruan, Tech. Sgt. Dale E. Mathews and Staff Sgt. Afton M. Ponce.
At least three geese broke through the aircraft’s windshield and knocked Stover and Ruane unconscious, the U.S. Air Force Aircraft Accident Investigation Board said. At least one bird struck the aircraft’s nose, damaging components of the automatic flight control system.
The air crew of the lead helicopter did not notice the birds, investigators said. Crews were using night vision goggles, which can make seeing birds difficult, investigators wrote. The goggles “have a limited field of view and inherently less than perfect visual acuity.”
Investigators placed no blame on the crew of the crashed helicopter, mission planning or aircraft maintenance.
Bird activity was supposed to be minimal in the area. The 56th was in possession of a bird activity report, effective the day of the crash, that indicated the Salthouse area had low bird activity, investigators said.
However, investigators also noted that wildlife officials observed a flock of about “400 geese, along with other birds,” in the area the day before the crash. Officials saw no geese on the day of the crash.
The report also noted that a December storm in the area of the Blakeney Nature Preserve, which is no more than 10 miles from the crash site, encouraged “the growth of vegetation that is undesirable to birds” and caused them to “find alternate feeding and roosting sites.”
Investigators said that Lakenheath officials had, in a January safety brief, “instructed aircrews to assume a moderate bird hazard condition for the duration of the migration season, unless otherwise briefed.”
The U.K. government regulates how airspace can be used, but a Royal Air Force spokesman said that there are no plans because of the accident to change the rules governing the airspace near Salthouse.
“Effectively, it was a freak occurrence,” the spokesman said, citing the weather.
Lakenheath officials said in a statement that it is “difficult to attribute any operational adjustments directly to the investigation results, because our mitigation plans are always being adapted to face current avian concerns.”