History of Flight
On September 24, 2009, at 1843 mountain standard time, a Eurocopter AS 350 B3, registration N103LN, was landing at St Mary's Helistop in Tucson, Arizona. According to the pilot, when the helicopter was approximately 5 feet above the landing pad, it began an uncommanded left yaw. The pilot applied right antitorque pedal, but there was no response. He then rapidly lowered the collective, rolled off the throttle, and made a hard landing. After landing, the helicopter came to rest facing the opposite direction of its approach. Inspection revealed buckled skin on the tail boom about 2 feet aft of its attachment point. The pilot reported winds from the west at 2-3 knots, with the helicopter landing to the west. A weather observation from Tucson International Airport, 6 nautical miles southeast, reported winds from 350 degrees at 7 knots at 1853.
A hospital surveillance camera recorded the landing. The video, at approximately one frame per second, shows the helicopter making a steady approach. At 6:41:53 pm, the tail boom light moves left and the landing light moves right, and by 6:41:57 pm, the helicopter has pivoted about 180 degrees while a few feet above the pad.
Personnel Information
The pilot, aged 60, held an airline transport pilot certificate for multiengine airplanes and commercial privileges for single-engine airplanes, rotorcraft-helicopter, and instrument-helicopter, issued on September 6, 2009. He had a second-class medical certificate dated January 14, 2009, with a limitation requiring glasses for near vision. The pilot reported 12,841 total flight hours, including 6,710 hours in rotorcraft and 204 hours in the AS 350 B3.
Aircraft Information
The four-seat, single-engine helicopter, serial number 3128, was manufactured in 1998 and configured for emergency medical services. It was powered by a Turbomeca Arriel 2B engine rated at 747 horsepower. The last inspection was on July 17, 2009, under an approved aircraft inspection program. At the time of the accident, the airframe had 5,244 total hours, and the engine had 4,969 hours.
Examination Findings
An FAA inspector examined the helicopter and found all control linkages in place, with continuity established from the antitorque pedals, cyclic, and collective to the flight control surfaces. The Vehicle and Engine Multifunction Display (VEMD) data for the accident flight (flight 368) showed no failure diagnosis pages; such pages are only generated when an anomaly is detected. The most recent flight with failure diagnosis pages was flight 324, 45 flights earlier.
The tail rotor servo actuator (part number SC5072, serial number 1275) was removed and sent to the NTSB. On December 2, 2009, it was examined at Hawker Pacific Aerospace in Sun Valley, California. The servo was visually examined for damage and leaks, with nothing unusual noted. It was then placed in a test fixture, pressurized to 580 psi, and subjected to 100 extension-retraction cycles. The servo exhibited no leaks and performed within designed parameters.