“I’ve heard that an experiment determined that private pilots survive an average of three minutes after accidentally entering IMC. Is that right?” — Graeme P.
“There’s no question that non-instrument rated pilots should stay out of the clouds. Year after year, accidental flight into IMC is the leading weather-related killer of general aviation pilots. But the often-cited “178 seconds to live” (a.k.a., three minutes) is misleading.
The “178 seconds” number comes from a University of Illinois study done in 1954. It’s worth a read. However, the study wasn’t designed to test how long a typical pilot would survive an accidental IMC encounter. Instead, it was to test how successfully a particular escape method could be taught under very difficult conditions.
Twenty low-time pilots were selected, all with zero instrument time. They were put in a Bonanza with the attitude, heading, and vertical speed indicators covered. None of them had flown a Bonanza before, the plane was loaded to maximum gross weight and maximum aft center of gravity, and a number of other things were done to make the scenario especially difficult. The pilots had to maintain control and execute a 180-degree turn to escape the simulated IMC conditions. None were successful, and the average time to loss of control was 178 seconds.
It should be no surprise the pilots failed under those conditions. They did much better after a short period of instruction: All but one maintained control and made a successful 180.
The takeaway from this study shouldn’t be the hopelessness of accidental IMC encounters. Instead, it’s that even minimal instruction on escape techniques can make a massive difference in the odds of survival. A private pilot can and should develop solid instrument skills so this scenario doesn’t end in disaster.”
Have you ever entered instrument conditions accidentally?