The ATSB continues to investigate accidents—many fatal—that involve pilots flying with reduced visual references.
Under visual flight rules (VFR), it is crucial that pilots have sufficient visual reference to see and avoid obstacles. Visual cues are also required to maintain orientation so VFR pilots know which way is up and can maintain control of their aircraft. Visual reference can be reduced by cloud, darkness, or atmospheric conditions such as rain, fog, smoke or haze. Two main risks are associated with flying in limited visibility:
- loss of orientation, leading to loss of control of an aircraft and an uncontrolled flight into terrain
- insufficient visibility to enable a pilot to see and avoid obstacles while remaining under control, known as a controlled flight into terrain.
The same hazards can also apply during night flight because there are often fewer visual cues at night, even though the visibility may be good.
What can you do?
Whether it’s a dark night or cloudy conditions, the dangers of flying with reduced visibility are significant, but avoidable.
- Know your limits. VFR pilots should use a ‘personal minimums’ checklist to help control and manage flight risks through identifying risk factors that include marginal weather conditions. Only fly in environments that do not exceed your capabilities. For visual flight at night, ensure you are both current and proficient with disciplined instrument flight.
- Plan ahead. Avoid deteriorating weather by conducting thorough pre-flight planning. Ensure you have alternate plans in case of an unexpected deterioration in the weather and making timely decisions to turn back or divert.
- Be equipped. Before committing to departing on a visual flight at night or close to last light, ensure your aircraft is appropriately equipped and consider all obtainable operational information, including the availability of celestial and terrestrial lighting.
- Don’t be fooled. Some nights and some terrain are darker than others. Excellent visibility conditions can still result in no visible horizon or contrast between sky and ground. Inadvertently flying into instrument meteorological conditions is also harder to avoid at night.
- Know your position. Always know where the aircraft is in relation to terrain, and know how high you need to fly to avoid unseen terrain and obstacles.
- Don’t press on! Pressing on into instrument meteorological conditions with no instrument rating carries a significant risk of severe spatial disorientation due to powerful and misleading orientation sensations with no visual cues. Disorientation can affect any pilot, no matter what their level of experience.
The following ATSB avoidable accident reports provide case studies and guidance on managing the risks of flying with reduced visibility.
- Loss of control and collision with water involving Piper Aircraft Corp PA-28-235, VH-PXD, 33 km SSE of Avalon Airport, Victoria on 29 January 2016
- VFR flight into IMC involving de Havilland DH-84 Dragon VH-UXG, 36 km SW of Gympie, Qld, on 1 October 2012
- VFR flight into dark night involving Aérospatiale, AS355F2 (Twin Squirrel) helicopter, VH-NTV, 145 km north of Marree, SA on 18 August 2011
- VFR flight into dark night conditions and loss of control involving Piper PA-28-180, VH-POJ, 31 km north of Horsham Airport, Vic., on 15 August 2011
Pilots can learn strategies to avoid the dangers of flying into adverse weather conditions in the ATSB booklet, Accidents involving Visual Flight Rules pilots in Instrument Meteorological Conditions.
The ATSB has also released a booklet, Visual flight at night accidents: what you can’t see can still hurt you, to help pilots better understand and manage the dangers of flying at night.