VFR into IMC

VFR Flight into IMC is one of the most common causes of fatal accident worldwide.

The best mitigation to avoiding flight into cloud is to obtain a thorough weather briefing prior to flight and to make early decisions not to fly, or to turn-around, or divert to an alternative aerodrome during flight, if required.

Get-there-itis, or the temptation to continue with a flight, is one of the most common contributing factors in VFR into IMC accidents. Pilots should be particularly aware of the dangers of continuing a flight in order to reach a pre-determined timeframe or to attend an event. It is better to explain why you were unable to make it to your destination on time than to be involved in an accident en-route.

Research shows that the likelihood of a pilot making a decision to not continue with a planned flight greatly decreases following the decision to take-off. Once pilots are airborne they are much more likely to justify their actions or to press on into deteriorating weather. The likelihood of a VFR into IMC accident also continues to increase throughout the flight as pilots try and convince themselves that they are almost there or are too far to turn back now.

VFR into IMC accidents are particularly dangerous when combining bad weather with terrain and obstacles.

All pilots should be aware of the factors that may result in reduced decision making which may lead to pressing on into deteriorating weather.

KNOW YOUR WEATHER REQUIREMENTS

Section 7.02 of the CASR Part 149 Manual of Standards (MOS) states that before commencing a flight, the pilot in command must study:

Authorised weather forecasts and authorised weather reports for:

the route flown, and
the departure aerodrome, the planned destination aerodrome, and any planned alternate aerodrome; and
any other reasonably available weather information that is relevant to the intended operation.

If the information is studied more than 1 hour before commencing the flight, the pilot in command must obtain, and review, an update to that information before the flight begins.

Authorised weather forecasts are:

1 of the following:

for an operation at or below 10,000 ft AMSL — a GAF or a GAMET area forecast;
for any operation — a flight forecast;

a wind and temperature forecast

An authorised weather forecast used to satisfy the requirements must be valid for at least 30 minutes before, and 60 minutes after, the planned ETA.

If a weather forecast is unable to be obtained before departure, an aircraft may commence a flight if:

an authorised weather forecast or an authorised weather report for the flight is not available; and
the pilot in command reasonably considers that the weather conditions at the departure aerodrome will permit the aircraft to return and land safely at the departure aerodrome within 1 hour after take-off.

However, if a weather forecast is unable to be obtained before departure and the conditions above are met, the pilot in command must return to the departure aerodrome if:

the authorised weather forecast required for the planned destination aerodrome is not obtained within 30 minutes after take-off; and
the pilot in command has not nominated a destination alternate aerodrome if required to do so under Part 91 requirements.

SPATIAL DISORIENTATION

VFR flight into IMC is extremely dangerous due to the onset of spatial disorientation. Spatial disorientation may occur when a pilot loses reference to a horizon. This results in a loss of 80% of the input you need for orientation. As you continue, any change in attitude will affect your sense of balance.

Before you know it, you are likely to lose all sense of direction and orientation. This is explained further in the video below:

Spatial disorientation following flight into cloud most commonly results in loss of control of the aircraft. In many cases this leads to collision with terrain with fatal outcomes.

Research in the 1990s showed that on average, it took 178 seconds for a pilot to lose control of an aircraft following flight into cloud. This is referred to by CASA as 178 seconds to live.

PRECAUTIONARY LANDINGS

It is often extremely difficult to make the decision to conduct a precautionary landing during flight, particularly if there are limited options for landing. This is likely made even more difficult for aircraft owners who do not wish to damage their aircraft.

At the end of the day, precautionary landings (like forced landings), are there to save pilots, not aeroplanes.

Making a proactive decision to land resulting in possible damage to an aircraft is almost always a better option than ending up in a loss of control accident following flight into cloud, the result of which is almost always fatal.

Top tips to avoid VFR into IMC

Conduct thorough pre-flight weather planning prior to flight and obtain updated reports where possible.
Avoid pressure to continue with a flight if conditions are marginal.
Avoid complacency when flying familiar routes - VFR into IMC accidents often occur within a pilot's local area.
Have an alternate destination in case weather conditions deteriorate.
Make the decision to turn around early, even if you are close to your destination.
Check that conditions are not closing in around and behind you.
If conditions continue to deteriorate, carry out a precautionary landing in a suitable location.
If you find yourself above cloud, do not hesitate to contact air traffic control for directions or assistance (admitting you have made a mistake is better than not making it home).

In the event you do inadvertently enter IMC – Do not panic.

Maintain a scan on your instruments and avoid becoming fixated on any one instrument. Always trust your instruments.

Maintain a stable flight path and make only gradual turns if required.

Decision making in order to navigate out of cloud will depend on a number of factors including weather and terrain. It may be best to maintain straight and level and climb above cloud or to slowly descend out of cloud if operating over known terrain. It may also be best to make a gentle 180 degree turn to fly back out of cloud into known clear air.

Flight into IMC is risky business. Remember, it's always better to avoid venturing into IMC in the first place rather than finding yourself in trouble and struggling to find your way out. Stay safe, stay clear of clouds (or smoke, dust, or other sources of reduced visibility)!

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