Training for the “real world” can be fraught with risks, especially when that training is in snow-covered, mountainous terrain. On Feb. 22, 2022, two Sikorsky UH-60 Black Hawk helicopters belonging to the Utah National Guard were conducting training to prepare their flight crews for this threatening environment. As the helicopters approached the landing zone near the boundary of the Snowbird ski resort, the powerful downwash from their rotors whipped up the snow surface into a localized blizzard, completely immersing both helicopters in a blinding sea of white. After the mini blizzard subsided, it was evident that both helicopters were badly disabled, with one of them lying completely on its side and portions of the rotor system widely scattered.

The details of the flights’ final seconds are currently under investigation and the accident reports won’t be completed for many months. Fortunately, the abrupt landings of both helicopters did not result in major injuries to our service members.

This example highlights an important question we face in our profession, both for military and civilian aviation: Can we create an effective, low-risk learning medium to enhance the training of human factors?

This question is particularly timely because our aviation profession is currently adding thousands of entry-level pilots who are moving rather rapidly from general aviation flight training into advanced air transport operations. This emphasizes the importance of providing excellent training to prepare them for the challenges of adverse flight operations. It is especially important to help the incoming generation understand and apply the important lessons of human factors, especially because human factors tend to be the root cause of most accidents.

Lethargy and Confined Seats

Airline recruiters are converging on college aviation programs, using examples of recent graduates who are now flying international routes. The students quickly have visions of strolling the Champs-Élysées and indulging in fine cuisine in Paris on glamourous layovers.

Hence, when 23 students promised that they would behave on a Global Engagement college trip to Europe in May 2019, a large objective of the formal course was to expose them to a wide spectrum of real-world aviation human factors without the risk.

This provided firsthand experience of the effects of circadian rhythm desynchronization during trans-meridian eastbound long-distance flights. It also exposed the students to the physiological effects from confinement in small seats for extended periods of time in a cabin altitude of roughly 8,000 ft., and other common effects from high-altitude, long-distance flying to include lethargy and dehydration.

The all-night flight from New York JFK International Airport (KJFK) to Zurich Airport (LSZH) arrived at roughly 3 a.m. on our body clocks. I chuckled at the weary students when they deplaned in Zurich, and said with only a slight amount of empathy, “Welcome to the glamorous life of being an international pilot! Isn’t it great?” Tired groans and dragging feet were pervasive throughout the group. To turn this into a practical exercise, the class members were asked to make relatively simple decisions, such as reading the train schedules to proceed to our next destination or deciding on food choices. They observed in each other a decrease in communication, decreased motivation to perform low-demand tasks, more distractions by discomfort and increased irritability.

During the next couple of days, the students experienced the difficulties of an eastward time shift in their circadian rhythms. They also experienced that the timing of sleep is the critical factor controlling the duration of sleep. Their attempts to sleep outside of their body clock’s “normal” sleep was more disturbed and less restful than sleep during the usual body time.

These students had previously studied fatigue during their classroom training. However, there is a vast chasm in the effectiveness between classroom discussions and actually enduring these effects in a real-world setting. A number of the students, who previously had lofty dreams of flying international flights, decided that their bodies weren’t tolerant of the circadian rhythm desynchronization and reset their career goals to focus on domestic daytime flying.

Mountain Shadow

At the top of Mount Pilatus above Lucerne, Switzerland, we had a perfect spot to enjoy looking at the scenic airport of the Pilatus Aircraft factory. As the sun started setting, we had a fabulous viewing platform to watch the mountain shadow effect. We watched as the shadow from majestic Mount Pilatus immersed the terrain below in shade that evolved into darkness nearly 90 min. earlier than official sunset. Lights in the houses and streetlights far below began to illuminate long before official sunset. If any aircraft had been on approach to the airport, the pilots would not have sufficient ambient lighting to see and safely avoid unlighted terrain during periods of darkness before official night.

Meanwhile, up on top of the majestic peak we were still immersed in sunlight, much like an aircraft at an altitude above the terrain. This was a perfect vantage point to discuss that pilots would experience rapid decreases in ambient illumination during the approach to a mountain bowl airport where terrain features rise far above the horizon and reduce the amount of illumination at lower elevations. The ability of eyes to fully adapt to the rapid change in illumination is constrained. This discussion heightened student awareness that the night restrictions on approaches at mountain bowl airports may not sufficiently mitigate the potential hazards of darkness.

Experiencing Whiteout and Vertigo

The itinerary of this trip included traveling up to the Klein Matterhorn. At 12,740 ft. ASL, it is the highest place in Europe that can be reached by an aerial tramway. This location is far above timberline, where there are no trees, and on the day of our visit, “flat-light” conditions existed. The students discovered that depth perception goes to zero in flat light, easily leading to vertigo. It was easy to misjudge speed and closing distances. The lack of contrast over a snow-covered landscape was immensely disorienting. They learned the difficulty of maintaining balance and making appropriate physical movements to stay in control. This was a great demonstration of the very real risks of degraded visual environments for pilots attempting to land in snow-covered terrain during flat-light conditions.

Afterward, we had the opportunity to talk with staff at the famed Air Zermatt, who described their techniques for landing in snow-covered terrain with flat light. Natural references (trees, rocks) in the vicinity of the proposed landing spot can help. The expert ski patrollers who might be on scene at a rescue site are equipped with markers, weighted flags, smoke bombs, red shop bags or dye markers. Smoke grenades work well as markers and wind indicators. The rescuers are even trained to kneel in the snow in a stationary position with their back to the helicopter to provide a reference.

In Part 2, we’ll discuss the effects of high-altitude physiology and visual illusions.