What happened
On April 9, 2010, at approximately 0124 PDT, a Bell 222U, registration N222UT, was preparing for takeoff at the Santa Maria Public Airport (SMX) in California. The aircraft, operated by California Shock-Trauma Air Rescue, was undergoing engine start operations when a nylon tie-down strap, which had been securing a tail rotor blade to the tail boom, broke.
The pilot, unaware that the strap had failed, proceeded with the flight to the Marian Medical Center Heliport (1CL8). During a subsequent departure from the heliport with a patient and passenger on board, a flight nurse noticed material wrapped around the tail rotor drive shaft. The pilot shut down the engines and removed the remaining strap material. Believing the aircraft was undamaged, the pilot continued to a medical facility in Madera, California, landing at approximately 0346.
Upon further inspection under better lighting, the pilot discovered damage to the tail rotor blade and other components. The aircraft was subsequently removed from service.
The investigation
Maintenance personnel examined the aircraft and determined it was unairworthy. The investigation of the tail rotor assembly revealed that one blade had scratches and indentations in its skin. Additionally, the four spherical bearings on the two pitch change links were seized, and the links themselves were bent.
Regarding the preflight process, the pilot stated that during the nighttime walk-around inspection, he observed a flight nurse moving to the opposite side of the helicopter and assumed the nurse had untied the tail rotor strap. The pilot only removed the main rotor blade tie-down.
Records regarding the pilot's duty status showed that the pilot had been awake for approximately 15 hours prior to his 2300 sleep period on April 8. He was awakened at 0110 on April 9 for the flight assignment, having slept for only about two hours.