Human Factors Training In The Real World, Part 2
In Part 1, we introduced a Global Engagement course that exposed college students to a wide variety of real-world aviation human factors without the risk.
Academic materials in the classroom discuss the effects of high altitude on human and aircraft performance, but these healthy college students had a firsthand experience of high altitude during their side trip to the Matterhorn. As we stepped off the gondola platform and began walking up to the scenic plaza, everyone in the class immediately experienced shortness of breath and dizziness. Several students were asked to breathe into a clear plastic bag to illustrate how much moisture leaves the body when we exhale. This helped to illustrate how a body in the dry air of high altitude (such as an aircraft cabin) is in a constant state of dehydration.
As we traversed to a different ridgeline of the Matterhorn massif, the weather changed from complete whiteout to brilliant sunshine. Our group had to stop immediately because we were temporarily blinded. Fortunately, we were within the marked confines of a groomed ski slope, because outside of these limits are unmarked hazards such as crevasses, which can be fatal. After we donned protective eyewear, we could see the stunning snow-covered scenery and markings that designated the boundary between the safe conditions of the “on piste” ski trail and the “off-piste” areas.
Snow reflects 80% of the sun’s rays, and activities at higher altitudes experience even more glare because UV radiation increases 4-5% every 1,000 ft. above sea level. Intense bright light was not only coming from the sun above but also from the reflection off the snow. Glare and bright sunlight is not only distracting and causes distortion, it also can hurt the eye and even cause temporary blindness. This was a great lesson on the importance of proper eye protection in the harsh high-altitude environment.
The modern economy’s appetite to be connected 24/7 means that thousands of new telecommunications antennas, power transmission towers and thousands of miles of wire are going up every year. Wire strikes happen often, and too frequently cause fatal injuries. The thin diameter of wires can make them practically impossible for a flight crew to see and avoid.
Mountain regions are often crisscrossed by a multitude of aerial wires. These include utility cables transporting electricity. Ski lifts are prolific in winter recreation regions. Aerial tramways enable tourists to ride to great heights over otherwise inaccessible scenic locations. In addition, some mountainous regions utilize aerial tramways for the transport of goods. On Feb. 3, 1998, a U.S. Marine Corps Northrop Grumman EA-6B Prowler aircraft, flying too low, cut a cable on an aerial tramway near the Italian town of Cavalese. Twenty people died as the gondola car plunged 260 ft.
The visibility of wires is affected by a number of factors, including atmospheric conditions, cockpit ergonomics, viewing angle, sun position, visual illusions, individual pilot scanning abilities and visual acuity, flight deck workload and camouflage effect of nearby vegetation.
During our many adventures in the alpine terrain, the students were able to assess the risk to aviation operations created by the relative invisibility of gondola cables and wires. This lesson was especially valuable to members of the class who were ROTC cadets hoping to someday fly military aircraft at low altitudes, as well as those hoping to fly EMS helicopters or aerial firefighting aircraft in mountainous regions.
The gondola ride to the top of the Klein Matterhorn is suspended many thousands of feet above the imposing glaciers. On one of our visits, the winds were significant, and the gondola swayed from side to side as well as vertically up and down. When these aerial tramways in the Alps are stopped due to forceful winds (or rare instances of mechanical failure in a drive mechanism), hoist-equipped helicopters become the primary means for rescuing stranded tourists. Premium helicopter handling skills are required to keep the external load cable and rescue specialist from getting tangled with the aerial tramway’s wires and structure. This was one of those “teaching moments” that happened unexpectedly, and fortunately it was well worth the unplanned addition to the original lesson plan for the outing.
Sloping Visual Illusions
In 1994, raging wildfires were threatening to blacken half of Central Idaho’s timber. Military resources were called upon to provide support. On Sept. 23, a Boeing CH-47D Chinook with five people aboard was approaching to land at a temporary helispot near McCall, Idaho. From the air the helispot had relatively sufficient dimensions away from tall trees and appeared to be relatively flat. Unfortunately, this was a visual illusion that wasn’t discovered until the Chinook’s front landing gear touched down on the 11-deg. slope. The helicopter began sliding backward, whereupon the front rotor hit the ground and the fuselage. The back rotor lifted the fuselage, which then fell onto its right side. Flying debris caused the nearby wildland firefighters to duck for protection from the potentially lethal projectiles. Unfortunately, one helicopter crewmember was killed.
The students had a perfect viewing platform from the Klein Matterhorn to observe helicopters from the famed Air Zermatt perform rescues on the foreboding terrain. During our hikes and ski outings we would pick out a possible landing spot as if we were flying an EMS helicopter tasked to pick up an injured victim. Then we would hike or ski to the area and see firsthand the actual angle of the spot. This was a great hands-on exercise to demonstrate the difficulty of trying to assess the suitability of the terrain for a temporary landing spot, especially when the nearby terrain is mountainous.
Restrictions to Visibility
A related lesson was taught on top of a peak back in North America when students participated in a summertime hike to the top of the Snowbird ski resort. We rested to enjoy the thin, dry mountain air as smoke from a distant wildfire drifted in our direction. Eventually, the smoke began to obstruct the visibility. Soon it was difficult to discern the horizon or see objects such as terrain. The gray smoke inhibited the contrast in colors, which further decreased the eyeball’s ability to accurately see and estimate the size and distance of other objects. The students observed how visibility into the direction of the sun was basically obscured. As we descended from the mountaintop, we could see how two adjacent ridgelines composed of the same vegetation and color can trick pilots into thinking it is merely one ridge. This has caught many pilots (in the backcountry or during aerial firefighting) by surprise.
In the final part of our article, the students learn about snow composition and how to prepare a landing site for an EMS helicopter.