Survive Inadvertent IMC The Old-Fashioned Way

if youve been around general aviation for any time at all, by now you should not be surprised to learn that attempted VFR flight into instrument metereological conditions (IMC) and its close cousin, loss of visual references at night, consistently rank as the most lethal type of GA accidents. Although the numbers (thank goodness!) have recently begun to decline, about seven out of every eight-nearly 90 percent-of those accidents are still fatal. Thats largely because, as current NTSB Vice Chairman Bruce Landsberg puts it, they tend to end in flight into terrain, either controlled or (more often) uncontrolled. In both cases, prospects for survival are meager.

David Jack Kenny

Sunday, March 17, 2019 at 12:00 AM ET

Verified

Reproduced here, and below, are instructor’s notes made during training flights with subject 13. When the study began, this person was 48 years old and held a private certificate. The non-instrument-rated pilot had accrued some 500 hours’ total flight time in an Ercoupe, a Stinson 150 and a Cessna 140. At the beginning of the study, the pilot needed only 124 seconds—far short of the 178-second average—to lose control.

Key Takeaways:

Inadvertent VFR flight into Instrument Meteorological Conditions (IMC) is a leading cause of fatal general aviation accidents, with non-instrument-rated pilots often losing control in an average of 178 seconds.
A 1954 University of Illinois study developed a simple, instrument-based (using altimeter, airspeed, and turn coordinator) recovery technique that could be learned in just a few hours.
The study demonstrated that after this brief training, pilots successfully executed the "hands-off" recovery procedure in 59 out of 60 simulated IMC encounters, drastically improving their ability to maintain control.
Despite its proven effectiveness and initial widespread adoption as the "180-Degree Rating Course," this direct, life-saving technique was eventually superseded by broader, more complex instrument training mandates, raising questions about current training's adequacy for real-world inadvertent IMC encounters.

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Editor’s Note: A sidebar in Mike Hart’s February 2019 “Losing Orientation” highlighted a 1954 University of Illinois study finding that a non-instrument-rated pilot who inadvertently encounters instrument conditions will last, on average, 178 seconds before losing control. We thought the study deserved some additional scrutiny.

If you’ve been around general aviation for any time at all, by now you should not be surprised to learn that attempted VFR flight into instrument metereological conditions (IMC) and its close cousin, loss of visual references at night, consistently rank as the most lethal type of GA accidents. Although the numbers (thank goodness!) have recently begun to decline, about seven out of every eight—nearly 90 percent—of those accidents are still fatal. That’s largely because, as current NTSB Vice Chairman Bruce Landsberg puts it, they tend to end in flight into terrain, either controlled or (more often) uncontrolled. In both cases, prospects for survival are meager.