Santa Maria, CA, USA
N222UT
BELL 222U
On April 5, the pilot reported for work at 0730 to begin a daytime work shift. He was off duty on April 6 and 7, and on the 7th he went to bed at midnight. In the morning, he awoke at 0800. According to the pilot, he was aware that on the 8th he was scheduled to work a nighttime shift, but he remained awake all day. He reported for work at 1930 to begin his nighttime shift. During his preflight inspection at the beginning of his shift, he noted that both the tail rotor and a main rotor blade were tied down. He stated that he went to sleep at 2300 after being awake for 15 hours. On April 9, after sleeping about 2 hours, he received a duty call about 0110 and was dispatched for the accident flight. During a walk-around inspection in the dark, he observed a flight nurse proceed to the opposite side of the helicopter. According to the pilot, he assumed that the flight nurse had untied the tail rotor tie-down strap. He only removed the main rotor blade's tie-down strap. The pilot's failure to ensure that the tail rotor blade's tie down was removed was an error of omission, indicative of fatigue impairment. During the engine start operation, the tail rotor's strap broke. This resulted in damage to a tail rotor blade and all of the pitch change links. The pilot was unaware of this event, and he flew to the designated hospital to pick up a patient. With the patient on board during the subsequent engine start operation, a flight nurse observed broken tie-down strap material wrapped around the tail rotor driveshaft. The pilot shut down the engine. With the assistance of the flight nurse, the pilot removed the tie-down material. He then flew the patient on the prescribed emergency medical services flight and landed uneventfully at the next hospital. Thereafter, the pilot reinspected the helicopter and observed that it was damaged. The company's director of maintenance inspected the helicopter and found it unairworthy. The damaged tail rotor blade and pitch change links were unserviceable and were discarded. The blade was observed to be scratched, and it had voids in its composite material structure. The pitch change links were bent and their bearings were seized, compromising the flight control system.
HISTORY OF FLIGHT On April 9, 2010, about 0124 Pacific daylight time, a Bell 222U, N222UT, owned and operated by California Shock Trauma Air Rescue (dba CALSTAR), was substantially damaged while standing with its engines operating in preparation for takeoff from the company's emergency medical services (EMS) operations base at the Santa Maria Public Airport (SMX), Santa Maria, California. Neither the airline transport certificated pilot nor the two flight nurses were injured during the positioning flight that was performed under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed at the time of the dark nighttime flight, and a company flight plan had been filed. The flight was originating at the time of the mishap. CALSTAR personnel reported to the National Transportation Safety Board investigator that at SMX, prior to the pilot's 0110 flight assignment duty call, one of the tail rotor blades had been tied down to the helicopter's tail boom with a strap. It was the pilot's responsibility to preflight the helicopter prior to flight. Following the pilot's engine start operation, as the tail rotor blades began rotating in preparation for takeoff, the tie-down strap broke. Unaware of the mishap, the pilot departed SMX and flew to the Marian Medical Center Heliport in Santa Maria (1CL8) and landed about 0131. Just prior to the pilot's 0242 departure for the EMS flight with a patient and passenger on board, one of the pilot's flight nurses who was standing outside the helicopter observed material attached to the helicopter's tail rotor area. The nurse brought the anomaly to the pilot's attention. The pilot shut down the engine and examined the helicopter. Nylon rotor blade tie-down webbing was found wrapped around the tail rotor's drive shaft. The pilot and flight nurse removed the webbing material, and the pilot inspected the helicopter. Believing that the helicopter was undamaged the pilot, along with the EMS crew, patient and family, departed 1CL8. The pilot flew under Part 135 to a medical facility in Madera, California, and landed about 0346. Thereafter, with better illumination, the pilot performed a more detailed inspection of the helicopter during which he observed damage to one tail rotor blade and other anomalies. The pilot notified CALSTAR's management of his observations, and the helicopter was immediately taken out of service for repairs. HELICOPTER DAMAGE CALSTAR's director of maintenance (DM) assessed the damage to the helicopter's flight control system components, and he determined that the helicopter was not airworthy. The DM stated to the Safety Board investigator that he observed damage to one of the tail rotor blades. The blade was scratched and exhibited indentations in its skin (voids). An examination of the two pitch change links (one for each of the tail rotor blades) revealed that their four spherical bearings were seized, and the links were bent. The amount of deformation was visually apparent. In accordance with guidance provided by Bell Helicopter, damage to the composite material rotor blade and pitch change links was significant and not repairable. Accordingly, these components were discarded. No additional examination of these components was performed. ADDITIONAL INFORMATION Evidence of Damage According to CALSTAR's Director of Operations (DO), operation of the helicopter immediately prior to the accident flight occurred on April 7, 2010. This flight was not performed by the accident pilot. The pilot who flew the helicopter on this date did not report experiencing any flight anomalies or damage to the tail rotor blades or pitch change links. Also, just prior to the accident flight, when CALSTAR's maintenance personal performed their routine daily inspection of the helicopter, no damage was observed. Fitness for Duty The pilot's recent work shift schedule was reviewed during the Safety Board investigator's April 16, 2010, examination of company records and interview with the pilot. The records indicated that on April 5, the pilot began a daytime work shift at 0730. He completed work at 1930. The pilot reported that he was off work on April 6 and 7, having experienced back pain. The pilot stated that he went to bed at midnight on April 7. According to the pilot, on April 8, he awoke at 0800, had a 0930 adjustment with a chiropractor, and felt fit for duty. The pilot stated that he remained awake the remainder of the day and evening, and he reported for work at 1930 to commence a nighttime duty shift. Upon arriving at work, he noted that one main rotor blade and the tail rotor had been tied down. The pilot indicated that at 2300 when he retired for the evening, he promptly went to sleep. He had been awake about 15 hours. After sleeping soundly for about 2 hours, he was awakened at 0110 to respond to the subject flight duty call. The pilot reported that he proceeded to the helicopter and placed his flight helmet on the seat. Thereafter, he performed a walk-around inspection. The helicopter was parked in a very dark area with little illumination. However, he had a flashlight available, in addition to light from a nearby trailer. The pilot stated that he observed a flight nurse proceed to the opposite side of the helicopter, and he assumed that the flight nurse had untied the tail rotor tie-down strap. The flight nurse was not a pilot. The pilot untied the main rotor blade. Pilot Responsibilities CALSTAR's DO reported to the Safety Board investigator that due to the prevailing wind condition at SMX, one of the tail rotor blades had been secured using a strap. The DO stated it was the pilot's responsibility to have ensured that the rotor blades were no longer tied down during his preflight walk around inspection just prior to takeoff. CALSTAR's "Policy & Procedures" directive, dated February 16, 2007, was issued by the company to address crew rest protocols. In pertinent part, it states that "all flight crewmembers are expected to arrive for duty in a well rested condition."
The pilot's inadequate preflight inspection to ensure that all tie-down straps were removed prior to flight. Contributing to the accident was the pilot's improper management of sleep opportunities during the preceding rest period, which likely contributed to the development of fatigue.
Source: NTSB Aviation Accident Database
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