The pilots were not wearing shoulder harnesses, so when the plane crashed, their heads hit the dash, injuring the pilot and killing the copilot. (There were also holes in the windshield, but these could not have been caused by their heads hitting it, because these windshields are very thick and are made to withstand bird strikes.) In reality, they would have been wearing shoulder harnesses, and prior to crashing, they would have locked the harnesses, so that they would not have to depend on the inertia reels locking. These shoulder harnesses would have prevented their torsos and heads from moving forward, so they would not have sustained these injuries.