Each year for the last several years, the NTSB has classified several dozen general aviation accidents as VFR-into-IMC. While they do not comprise a large percentage of the total number of GA accidents, they involve about two-thirds of weather-related accidents involving fatalities. Also, they are about four times more likely to be fatal when compared to other types of accidents (about 80% vs. 20%). Just under a quarter of these were pilots who probably didn’t fly into weather deliberately, but made an erroneous weather assessment—the NTSB terms the meeting of pilot and weather as ‘inadvertent‘ or ‘encountered.’ Unfortunately, the rest were more or less willful penetrations with more or less Darwinian consequences—over a third are classified as ‘continued’ flight into deteriorating or unsuitable conditions for the aircraft, pilot or a combination of the two.
‘178 SECONDS TO LIVE‘
Over ten years ago, the University of Illinois put 20 VFR pilots into simulated instrument conditions, and then carefully watched what happened next. While 20 is not quite a statistically significant number, the average time elapsed before control was lost was just under three minutes and that result has since become quite famous within the aviation community. In spite of those results, and in most aircraft, there is a horizon situated in front of the pilot at all times (albeit an artificial one). This suggests that VFR pilots may be looking at the instruments, but they’re not processing what they see. They see the instruments, but they keep flying by the seat of their… well, whatever they’re wearing.
CLINICAL ANSWERS FROM THE NTSB…
With consideration to the factors and causes involved in the accidents that it has studied, the NTSB often attributes them to the flight environment (weather, terrain, light conditions) and/or the flight crew (disorientation, aircraft control, lack of instrument time, flight and/or weather decisions). It’s worth noting that the most prevalent flight crew related factors however — the first three of the four listed above — apply after the pilot has already entered IMC. Other factors such as ‘aircraft‘ or ‘facility‘ are rarely listed as causal.
…AND LESS TANGIBLE FACTORS
Why do pilots continue VFR flight into IMC? Academic studies of accident data have led to some interesting conclusions. First, the total flight experience of VFR-into-IMC accident pilots is significantly lower (about two-thirds) than that of pilots involved in all other types of accidents. Almost three-quarters of those pilots who flew VFR-into-IMC and had an accident were trained to the private level or below. That may indicate evolution is at work; lower-time pilots have less experience interpreting real-time weather. When compared with other GA accident types, a significantly higher number of VFR-into-IMC accidents occur with passengers on board—which may suggest that pressure to perform is outweighing judgement. And the rate, severity, and factors involved in VFR-into-IMC haven’t changed.
HUMAN FACTORS
Here are some probable causes, not from the NTSB, but (with the exception of the last item) from experts in aviation psychology and human factors:
- Improper assessment: an early misdiagnosis of the weather, a lack of experience interpreting real-time changes, and the gradual transition itself. Academics would call this ‘recognition-primed decision-making.’
- Fear extinction: basic pilot training inculcates confidence in aircraft control and optimistic self-appraisals of abilities and judgment. Instructors must infuse their students with confidence to aid them in developing skills. A side effect is sometimes reduced awareness or perception of risk.
- Decision framing: pilots are more likely to commit to a decision (to continue flight into deteriorating weather) not only when they view decisions in terms of potential losses (time or money), but also when their entire approach to flying is goal-oriented.Better
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- : Pilots making
decisions framed in terms of gains in safety
- , have been shown in laboratory studies to arrive at risk-averse conclusions.
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- Someone’s watching: the presence or perceived presence of an audience creates social pressures that can translate mission completion into a matter of personal integrity. This in turn fosters the perception that inability to complete the flight translates to personal failure… rather than a display of skill through judgement.
- Other educated guesses: attitudes of invulnerability, habituated scud-runners who jog into that roach motel one last time, and of course, stupidity.
GET THE PICTURE — BRIEFERS, DUATS AND MORE
Some pilots take off without a clear image of the weather (or a weather briefing). Getting a good briefing takes time, practice, and a certain amount of discipline, but learning to do it right will also develop skills essential to acting as pilot in command—communicating with an external source to accurately and efficiently get all the information you need. I’d advise new pilots against DUAT-only self-briefings on all but the nicest days — or simply as a preface to a live briefing. If you do get a DUAT printout on a grey day, follow it with a comparison reading from the crystal ball of Flight Service. (It’s still free, but who knows for how long.) I’ll admit I can understand how one’s eyes might glaze over on hearing a term such as ‘closed low aloft,’ but the best way to learn is to jump into the game and ask questions… lots of them. En route, call Flight Watch on 122.0. (Be sure to tell them roughly where you are, so the right one can answer.)
Obviously, if there’s a line of airmets or sigmets across your path, stay down.
EXTRA MEASURES
Get that instrument rating. But for starters, the best way to gain the upper hand on deteriorating weather is to start flying in it (legally). Pick a day when it’s marginal VFR, or even 1000 overcast, and fly an IFR-legal aircraft with an instrument instructor. (Both will likely be available due to VFR-only student cancellations.) Look at the weather ‘big picture‘ and try to understand why you see what you see. Ask questions. Do some straight and level flight, 180-degree turns, and try to retain situational awareness using nearby airports, and terrain. See what navigation and communication feel like — even second-hand — while you’re in the soup. Then finish it up with an actual instrument approach. This applies to student pilots as well as VFR-only private pilots.
BOTTOM LINE: In-flight weather-related decision making hasn’t been given as much emphasis as it should. If you fly any length of time at all, sooner or later, it’s going to rain on your parade. Will it be a dry mouth, sweaty palm, collar-loosener, or as John Stuernagle from AOPA says, ‘Ho hum, guess I’ll have to file IFR.’ The great thing about getting an instrument rating is that paradoxically, even though IFR flying is 95% procedures — and a lot of them — it actually simplifies your flying. Plus, it makes you a more precise pilot, gives you more chances to fly… and elevates you to member in full standing in the ATC environment.
