Last night, after an eight-hour flight across the North Atlantic ocean, I flew into the world’s busiest airspace, acting as the pilot monitoring. I suddenly found myself perplexed by a right roll into an unexpected course change. My monitoring had obviously failed. The pilot-flying had made a mistake in his automation input, and the result of this man-machine interface error was the all-too-common response from both of us — “What’s it doing now?”
The aspect of that error that I find most fascinating is not how or why it occurred, or what circumstances of task saturation, fatigue, distractions, or countless other factors came together in subtle ways to facilitate the error. The most interesting aspect is how easily and substantially perplexed I became by that unexpected rolling maneuver. My mind seemed to flick into denial — “How did it do that?! That’s not what it’s supposed to be doing!” It was a powerful, emotional, albeit wholly internal, response.
In retrospect, I find myself analyzing the extreme contrast between my response to that automation-flown lateral deviation and my usual response to automated pitch or altitude errors. Every time I’ve had an autopilot-flown aircraft make an unexpected pitch change, I suffered no confusion or internal conflict. My view of all that I recall, or any hypothetical ones I can imagine, is quite simple; I immediately recognize a pitch deviation as an error — plain and simple. It’s going up when it should be going down, or down when it should be level, etc. There is no mental hiccup. Recognition of mistaken pitch is, at least for me, a simple thing. I immediately correct the deviation manually, without any interest whatsoever in why it is happening, or what caused the automation to do the wrong thing. It requires nearly no thought at all. I step in and fix the pitch error by hand, knowing full well I’ll figure out the root of the error afterward.
When automated pitch does something other than expected, I just fix it — push CWS or AP disconnect and make the correction — and problem solved. From there it’s a simple push of the heading sync and Heading, then and Alt or VSpeed, and re-engage the autopilot; easy as 1 – 2 – 3. The airplane is now going exactly where I pointed it with so little effort that I can sit back and wind my watch, knowing I have plenty of time to figure out exactly how I screwed it up, and then fix it. So why do lateral deviations trick me into wasting more brain cycles than that?
Undoubtedly, some psychologist could postulate an answer. It probably has something to do with the roll. Wrong pitch? No problem — that’s not right. Unexplained roll? Not quite so easy. I’ve seen many pilots respond, “why did it just do that?” and then proceed down the path of trying to figure it out without first intervening to correct it. It’s almost as if we think the computer knows what it’s doing if it’s turning — “what did I miss?” If it climbs when it should be level, we are on it, right now, no questions. If it turns when it should go straight, we can be drawn into thinking we are unsure of where it should be going. It may be as simple as knowing our desired pitch is much more immediately concrete and tangible than having that same certainty about where, among the innumerable, indecipherable, five-letter waypoints we should be steering.
But, for pilots that have ever said “what’s it doing now?” understanding why our brains get so easily wrapped-around-the-axle by a lateral deviation is a worthless question. Understanding that this is exactly what we tend to do is the real nugget to pick up. Knowing we are easily suckered by that roll is the one thing that will turn seconds of confusion into a micro-second acknowledgement of our weakness, followed by quick, direct intervention to manually level the wings, sync heading, press HDG, ALT, AP, and then figure out why it did that, and what we want it to do next.
Last night, I watched feebly as the pilot-flying remained on autopilot and made not one but four useless rolls, back and forth, while trying to solve the mystery of why it was doing that. The folks in the back probably ended up more perplexed than we were.
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