The hazards of flying visually in poor weather have again been highlighted following the ATSB's investigation (AO-2011-085) into the fatal accident of a Bell 206L helicopter near South Turramurra, NSW.
On 22 July 2011 the helicopter, with a pilot and one passenger, departed from Rosehill, NSW on a private flight to the Sydney Adventist Hospital near South Turramurra.
As the aircraft neared its destination the pilot encountered low cloud and rain. Shortly after, witnesses saw the helicopter descending rapidly with the tail section separated. The helicopter collided with the terrain, fatally injuring both occupants. The investigation found it was likely that during manoeuvring in the area of low cloud and rain the pilot inadvertently flew into reduced visibility conditions. This led to the onset of disorientation and loss of control of the helicopter.
Accidents of this kind are still far too common and doubly tragic because most are avoidable. In the five years 2006-10 there were 72 instances of visual flight rules (VFR) pilots flying in instrument meteorological conditions (IMC) reported to the ATSB. Seven of these resulted in accidents and caused 14 fatalities. Statistically, about one in ten VFR into IMC events results in a fatal outcome.
A recently released ATSB avoidable accident booklet highlights the risks of flying visually into poor conditions.
The booklet offers some important key messages to pilots:
- It is essential to do your pre-flight planning and have alternative plans in case of an unexpected deterioration in the weather.
- Make timely decisions to turn back or divert.
- The risks of spatial disorientation are heightened when pressing on into IMC conditions.
- Use 'personal minimums' checklists to help control and manage flight risks by identifying risk factors including marginal weather conditions.
- Set passenger expectations by making safety the primary goal.