This case involves a tourism helicopter crash in Alaska that was allegedly caused by a mechanical part failure. The helicopter was cruising with a pilot and 4 passenger tourists at 800 feet when the pilot felt an impact. As the pilot slowed down for landing, she noticed a heavy mechanical sound and a strong vibration. The sounds and vibrations continued to worsen making it difficult for her to control the helicopter. During the landing, the main rotor blades contacted the tail boom and one of the tail rotor blades resulting in separation of the tail rotor gearbox support structure. As a result of the crash, several of the tourists suffered whiplash injuries and ongoing emotional distress. It was suspected that fatigue fractures in the attachment studs may have contributed to the accident. An expert metallurgist with aircraft expertise was sought to review the case and determine what parts may have failed and how.