OK, this might be a bit of a ‘one weird trick nobody knows’ clickbait avgeek troll headline — but this is a real paper on real research in a real journal. It’s in Safety Science, titled ‘An analysis of a pilot’s adherence to their personal weather minimums’, written by Professor Scott Winter et al.. Full citation at the end of the post. They studied certificated instrument pilots (who were also ERAU students) and how they adhered to both personal and FAA minimums while flying an ILS approach. The results were quite astonishing:
“The findings demonstrated 96.4% of participants descended below their stated personal weather minimums while 81.5% descended below the minimum published federal altitude.”
How did they do it? The research team at Embry-Riddle Aeronautical University in Daytona Beach, Florida, had 112 instrument-rated pilots fly an ILS approach in a simulator into low instrument meteorological conditions. What they didn’t know was the weather was set below minimums, forcing a missed approach. The simulator/research lab looked like this:
The purpose was to study whether pilots really adhere to stated ‘personal minimums’, which for these relatively inexperienced pilots (average total pilot time 264 hours) were higher than the absolute FAA minimums for the approach. I’d expect some non-compliance here, personal minimums are kind of aspirational, have a yeah yeah New Years Resolution feel to them. And it’s a simulator, no one is going to crash and die in a sim. Just a bit lower and I’ll show you how good a pilot I am! So 96% going below doesn’t surprise me.
But I’m very surprised that at real FAA minimums over 80% of the pilots kept descending. These are licensed instrument pilots, engaged in university research. Now, some were told they’d receive a possible $25 reward if a landing was completed, but that’s a lot less motivation than running out of gas or having to divert to an alternate and spend the night in a rubbish hotel. Still, $25 is a lot of money to an undergraduate student and it could welll tip the scales.
It didn’t The researchers report, “there was no significant difference in the lowest altitude which a pilot descended based on the external pressure condition for which they were assigned.” The four different conditions of financial or peer reward that were tested — made no difference. The story was the same with or without motivation to land:
“A high percentage of pilots (96.4%) descended by an average of 303 feet below their stated personal weather minimums for cloud ceiling (height), and 81.5% of pilots descended below the federal legal limit an average of 43 feet. All of these values are highly concerning.”
Six of the pilots never went around, and pushed on to a ‘landing’. The weather was 0 miles visibility 0 feet ceiling. Two of those six ended up in the grass next to the runway. Everybody received the $25 bonus.
The paper ends by saying “personal minimums only serve as a risk mitigation strategy if they are properly used, adhered to, and supported.” Not really surprising that almost every pilot blew past feels-good-to-say-it personal minimums.
What was surprising was the attempts to influence the pilot’s behaviour failed. Monetary or peer reward had no statistical influence on the altitude that missed approach was started. And the huge story is the overwhelming number of pilots that went below absolute minimums. This is Top Gun Maverick breaking the hard deck stuff. You don’t do it unless it’s some kind of two-engines-on-fire emergency.
Don’t be like these ERAU students. Just don’t.
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Reference:
Scott R. Winter, Stephen Rice, John Capps, Justin Trombley, Mattie N. Milner, Emily C. Anania, Nathan W. Walters, Bradley S. Baugh. (2020). An analysis of a pilot’s adherence to their personal weather minimums. Safety Science, Volume 123.
https://doi.org/10.1016/j.ssci.2019.104576
https://www.sciencedirect.com/science/article/pii/S0925753519321873
Do you access to the full paper? Pilots are allowed to descend below DA on an ILS during a go around.