On 1 December 2013, an Aérospatiale AS350B2 helicopter, registered VH-HRQ (HRQ), was on a return flight to Davis Base, Antarctica, with a pilot and two passengers on board. HRQ was one of two helicopters that were tasked to take a scientist and two field training officers to a penguin rookery at Cape Darnley. The helicopters refuelled during the return flight at a fuel cache on the Amery ice shelf, before departing to the south‑east for their next refuelling stop.
As a result of a rapid reduction in visual cues, the pilot of HRQ maintained about 150 ft above ground level. The pilots of both helicopters discussed the reduced surface definition and loss of visible horizon along their flight path and elected to return to the fuel cache until the weather improved. During the turn back to the fuel cache, HRQ descended and impacted the ice shelf. The pilot and two passengers were seriously injured and the helicopter destroyed.
What the ATSB found
The ATSB found that the pilot did not detect the descent during the turn back to the fuel cache. The ATSB concluded that, after initiating the right turn, the pilot probably became spatially disoriented. Factors contributing to the disorientation included a loss of visual cues as a result of the change in weather conditions, and a breakdown of the pilot’s scan of his flight instruments, resulting in collision with terrain.
What's been done as a result
Following this accident the operator introduced new helicopters equipped with an autopilot and other equipment to reduce pilot workload. They also introduced simulator training that is administered by an experienced Antarctic pilot, a situation awareness course, and training on the use of the autopilot in the new helicopters and limitations of the radar altimeter. The operator has also amended their operational documentation to prescribe minimum settings for radar altimeters, discuss the use of the autopilot in low visibility environments, and provide decision-making guidance in relation to early avoidance of, and action on encountering inadvertent white-out conditions.
This accident provides a timely reminder to flight crews of the importance of monitoring the flight instruments when encountering areas of reduced visual cues. The risks associated with flight in these conditions have been highlighted on the ATSB website as a SafetyWatch priority, along with a number of strategies to help manage the risk and links to relevant safety resources.