ERA24FA003 · Bell Helicopter Textron Canada 407

The accident flight, a night visual flight rules positioning flight, originated at an off-airport landing site the pilot had landed the helicopter at two days before the accident. An onboard image recorder captured the accident flight, which was the first flight of the day for the pilot. The video revealed that after a normal preflight inspection and run-up, the pilot initiated a near-vertical (straight-up) takeoff. Shortly after takeoff, the pilot stated aloud that it was too dark, and the helicopter began flying in an uncoordinated manor. The pilot continued the climb and accelerated forward, and the helicopter entered multiple unusual attitudes, with the primary flight display (PFD) indicating that the helicopter was in an extreme nose-down, right-bank attitude. The PFD displayed multiple visual warnings prompting the pilot to correct the unusual attitude. The pilot made large cyclic applications during the maneuvers, continued to verbally express confusion, and the engine torque/power was increased to its maximum. The helicopter then entered a descending right turn for 15-20 seconds. Shortly before impact, an aural alert for terrain was sounded, red chevrons on the PFD continued to display, and the helicopter’s spotlight began illuminating the dark forest below. The video stopped recording about one second after trees were observed in the pilot’s windscreen. Postaccident examination of the helicopter revealed no evidence of preimpact mechanical malfunctions or failures that would have precluded normal operation. Based upon the flight track data, onboard image recorder data, and astronomical data, the pilot initiated a visual flight rules flight into dark nighttime conditions over featureless terrain, which likely prevented the pilot from using visual references to the horizon. The pilot’s expressed confusion and large cyclic applications were likely the result of the pilot experiencing spatial disorientation. The onboard image recorder captured the pilot increasing the instrumentation and display lighting during the preflight inspection and he did not dim the instrumentation lighting before or during flight. Guidance from the FAA Helicopter Flying Handbook advises pilots to dim cockpit lighting for night operations to better identify outside terrain and hazard details. The guidance further outlined that taking off with cockpit lights that are too bright could cause reflections or glare off the windscreen, further reducing a pilot’s ability to fly by reference to the horizon outside. The pilot’s cockpit lighting settings likely contributed to the spatial disorientation. The pilot had available for his use an autopilot and stability augmentation system (HeliSAS) to help prevent the helicopter from entering unusual attitudes, in addition to helping the pilot exit an unusual attitude; however, the SAS mode was not engaged and remained in a standby mode for the entire flight. The SAS could have been engaged at the airspeed and altitudes through which the pilot was flying during accident flight. Review of the pilot’s experience found that an overwhelming majority of the pilot’s flight experience in the last 12 months was during daylight. Although, the operator did not record, nor where they required to record night currency, the pilot’s actions regarding lighting settings, his statement that it was “too dark,” and the ultimate loss of control due to spatial disorientation, likely indicate the pilot was not sufficiently current/proficient to fly the helicopter at night. The pilot had atherosclerotic and hypertensive cardiovascular disease that placed him at increased risk of a sudden impairing or incapacitating cardiovascular event. However, video evidence was not consistent with such an event occurring. Thus, it is unlikely that the pilot’s medical conditions contributed to the accident.

Verbatim NTSB analysis and probable cause from the NTSB dataset