Several waterfowl that smashed through a helicopter windscreen caused the crash that killed Capt. Christopher Stover of Vancouver and three other Air Force personnel on Jan. 7.Stover, a 2004 graduate of Evergreen High School, was piloting the HH-60 Pave Hawk helicopter on a search-and-rescue training flight along the English coast when it crashed.In a report issued last week, Air Force investigators determined that multiple bird strikes caused the crash of what they called the “mishap aircraft” or MA.“At least three geese penetrated the windscreen of the MA, struck the mishap pilot and mishap co-pilot, rendering them unconscious and thus unable to control the MA. Additionally, at least one goose impacted the front” of the helicopter, disabling its trim and flight path stabilization systems.Three seconds after being struck by the birds, the helicopter hit the ground, killing all four members of the crew, which also included co-pilot Capt. Sean Ruane, Tech. Sgt. Dale Mathews and Staff Sgt. Afton Ponce. The airmen were with the U.S. Air Force’s 56th Rescue Squadron, based at RAF Lakenheath in Suffolk, England.