ATSB warns of dangers of VFR into IMC

The Australian Transport Safety Bureau has released a new booklet warning pilots of the dangers facing VFR pilots who get caught in IMC.

The ATSB’s new Avoidable Accidents No.4 - Accidents involving Visual Flight Rules pilots in Instrument Meteorological Conditions booklet, coincidentally released on the same day of a Bell 206 accident in northern Sydney last week that claimed the lives of two people in atrocious flying conditions, highlights the dangers of pilots without an instrument rating flying into bad weather.

The dangers of flying VFR into IMC have been recognised for a long time, says the ATSB, yet VFR pilots still fly into deteriorating weather and IMC. From 2006-2010 there were 72 occurrences of VFR pilots in IMC reported to the ATSB. Seven of these resulted in fatal accidents, causing a total of 14 fatalities, meaning around one in 10 VFR into IMC events result in a fatal outcome.

ATSB General Manager Strategic Capability, Julian Walsh, said these accidents were all the more tragic because they were avoidable.

“We want to encourage pilots, no matter what their experience level, to develop the knowledge and skills to avoid unintentionally flying into bad weather,” Walsh explains.

“Weather does not always act as the forecast predicts. If the weather starts to deteriorate, unqualified pilots should make an early decision to turn back or divert before they are caught in cloud.

“Before they take-off, pilots need to carefully plan their flights and get up-to-date weather forecasts. If there’s any doubt, don’t fly.”

Flying into IMC can occur in any phase of flight, but 2005 ATSB research publication General Aviation Pilot Behaviours in the Face of Adverse Weather concluded that the chances of a VFR into IMC encounter increased as the flight progressed, with the maximum chance occurring during the final 20 per cent of the flight distance.

Avoidable Accidents No.4... presents case studies on the dangers of flying VFR in deteriorating weather, focusing on the key safety lessons learnt from each case.

“It should be noted that pilot decision making, particularly weather-related decision making, is complex and there is no single solution to the problem of VFR into IMC occurrences,” the ATSB concludes. “However, there are a number of measures which can be used to reduce the significant risk inherent in the operation of VFR into IMC.”

The ATSB's three key messages to pilots concerning VFR into IMC are:

 - Avoiding deteriorating weather or IMC requires thorough pre-flight planning, having alternate plans in case of an unexpected deterioration in the weather, and making timely decisions to turn back or divert.

- Pressing on into IMC conditions with no instrument rating carries a significant risk of severe spatial disorientation due to powerful and misleading orientation sensations in the absence of visual cues. Disorientation can affect any pilot, no matter what their level of experience.

- VFR pilots are encouraged to use a ‘personal minimums’ checklist to help control and manage flight risks through identifying risk factors that include marginal weather conditions.

To download the Avoidable Accidents No.4 - Accidents involving Visual Flight Rules pilots in Instrument Meteorological Conditions booklet in full as a PDF click here.