Inside the 777 simulator. The sensors attached to the author (left) capture a range of biometric signs.

| Photos: Kyle Johnson

I’m sitting in a 777 flight simulator at the Boeing’s research facility south of downtown Seattle, and I’m exhausted. I felt alert at the controls as we departed the virtual version of San Francisco International Airport 45 minutes ago. During the takeoff and climb there's plenty to keep my attention as veteran 777 captain and Boeing pilot Wiley Moore helps me through the procedures of flying a wide-body airliner.

Far from qualified to fly large jets like this, I'm working hard to keep up and make sure everything is done correctly. But once we're at cruise altitude and the pace slows down, it hits me. I just want to sleep.

"When you were resting [your heart rate] dropped quite a bit," says Chris Gast, a Boeing statistician pointing to the data after the flight. But it's not my actual heart rate that captures Gast's interest – it's how little my heart rate varies when I'm actually at the controls. Flying rested the day before, there was a much greater change. “The variability in your heart rate is way lower,” Gast says about my fatigued day.

I’m participating in a biometrics-capturing session in Boeing’s Crew Fatigue Monitoring study. The research is a cooperative project with Delta Air Lines to collect and interpret a massive data set examining the biometrics of tired pilots. The goal is to better understand the signals that indicate fatigue and perhaps implement a warning system based on the warning signs.

Tired pilots can be dangerous pilots. The FAA cites “unstable approaches, lining up on the wrong runway, and landing without clearances” as just a few examples of so-called fatigue-related events. And fatigue played a role in a 2009 crash near Buffalo, New York, that killed 50 people.

Like the 64 Delta pilots participating in the study, I am wired up with sensors that will supply the team with reams of data. Electrodes on my head and chest are monitoring brain-wave activity and heart rate. My eye movements are being tracked with a special eyepiece. On a bank of computer screens just outside the simulator door, the team of Boeing researchers are monitoring everything. Though the heavy analysis will be done in the months and years to come.

The Delta pilots arrive as a two-person crew and usually fly the first day in the simulator after a good night's sleep. The sim is an exact replica of a 777 cockpit, and the flights are extremely realistic. The crews have to do everything they would on a normal flight from the moment they sit down and get the passenger/cargo load and weather report, to pushing back from the gate, waiting for other airplanes as they taxi by, and talking to air traffic controllers. Some of the crews simulate long-haul flights to Asia and Europe, others simulate shorter domestic flights with more takeoffs and landings.

After the first day of flying rested, they are only allowed a few hours of sleep before their next virtual flight. In addition to the biometric measurements made during the sim sessions, the pilots also use a smartphone app to record their recent sleep schedules, record how alert they feel, and take a reaction time test that will further bolster the data collected in the study.

Following the same schedule as the Delta pilots, yesterday I flew rested on a full eight hours of sleep; today I’m flying tired with only three hours sleep, which Gast pointed out was easy to see when he looks at my data after the flights.

"You could say with a relatively high degree of certainty," Gast explains with the caution of a statistician, "if you tell me what your heart rate is, I can tell you whether you're fatigued or not,” he says, comparing my fatigue day to my rested day.

Pilot fatigue is nothing new. It has been a problem for airline pilots who often start work in the middle of the night, or may have to land an airplane after being awake for a long period of time.

Wiley Moore, a veteran of long-haul international flights and my Boeing instructor for the sim sessions, is no stranger to fatigue. He cites a typical example of a pilot leaving New York and heading to Europe for a late morning arrival, only to find fog at the destination forces a holding pattern.

"Probably the worst time you want to end up flying and making an approach," Moore says of the critical phase of flight coming after an all-nighter across the Atlantic. When he had multiple crews on a flight, Moore says he would have one of them show up ready to fall asleep in the crew rest area, while the other started the flight in the cockpit. But extra crew members are usually only available on flights longer than eight hours. And it's not only the flight time that matters, often pilots spend long hours getting to the airport, as was the case for the co-pilot in the Colgan Air crash.

After the issue of fatigue was raised in the investigation of the 2009 crash of Colgan Air Flight 3407, the Federal Aviation Administration implemented new rules to provide better opportunities for crew rest even though investigators ruled, "the degree to which it contributed to the performance deficiencies that occurred during the flight cannot be conclusively determined." But pilots still tilt their heads back while flying and "check for light leaks" in their eyelids, though it's not allowed under FAA rules.

Boeing researcher Lisa Thomas would like to help pilots in just such a circumstance. Thomas earned her Ph.D. analyzing cockpit displays and information. She says devices on the flight deck could detect fatigue based on biometrics, providing immediate feedback to the crew. She says the data from the Delta pilots is much more detailed than previous studies, paving a way to that goal.

"We go a lot further in finding out when the the airplane needs to notify the pilot that they need to do something to mitigate their fatigue," Thomas explains.

Gast, the Boeing statistician, is already tweaking the model he has developed that looks at the various "tells" from fatigued pilots. Mine was heart rate variability, while another pilot might have dramatic changes in how they blink, or they're eye movement (my eye movement was not helpful at all). Gast says an early version of the mathematical model prioritizes the signals for each individual pilot, depending on the variability between their rested and fatigued states.

"The real end product from my point of view – of course it's from a statistician so take it with a grain of salt – the algorithm is really the deliverable thing," according to Gast.

Gast says the early algorithm takes into account the variability rather than just one of the biometric signals reaching a certain point. "It asks the data, 'what differentiates A from B?' And then finds out what differentiates A from B and builds the predictive model based on that." If the model determines something like eye movement does not provide any clear changes between the rested and fatigue state, it gives zero weight to that signal Gast says.

The study will continue through the end of the year as more pilots spend some tired time flying the simulator, and the resulting data set will be the largest ever collected on fatigued pilots. Gast and the Boeing researchers will continue to work with the data, and hope to test a basic version of the monitoring capabilities in a test airplane in the coming years.

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