Rather than blaming pilots for the rare but often deadly failure to perform, the FAA and Industry Commercial Aviation Safety Team (CAST) have launched a multiyear, multipronged research effort with NASA and others to help find better ways to design cockpits and training to avoid the common human/machine-interface mistakes revealed by post-crash or post-incident analysis.
Behind the action is a 2010 analysis by CAST’s Airplane State Awareness (ASA) analysis group, which identified 12 major themes common to 18 commercial aviation accident and incidents worldwide in 2001 – 2010. While CAST is preparing to publish a series of mitigations based on its findings, officials realized more research is needed in certain key areas, including loss of attitude awareness (also known as spatial disorientation) and loss of energy state awareness (LESA), both of which fall into the broader category of crew attention management. Spatial disorientation was a factor in the loss-of-control crash of an Aeroflot-Nord Boeing 737-500 in Russia in 2008, and LESA will likely be the probable cause in the “too low and too slow” crash of an Asiana Airlines Boeing 777-200ER short of the runway at San Francisco International Airport in July 2018.
Complicating crew attention issues are the effects of unexpected events that startle or surprise pilots and can lead to inappropriate responses, “channelized attention,” which is focusing solely on an incorrect solution, or “confirmation bias,” which favours only the information that supports the pilot’s preconceived notion of what is causing the problem despite more compelling data to the contrary.
“CAST is looking to the aviation community to develop and validate prototype technologies to detect and mitigate attention issues for use in the design evaluation process
The first crew state measurements will come from a group of 12 volunteer regional airline pilots who will fly in the backseat of a specially equipped Aero Vodochody L-29 Delphin in Iowa City, Iowa, this summer as part of a loss of attitude awareness study. The University of Iowa’s Operator Performance Lab (OPL) is under contract to NASA to perform the work. Tom Schnell, OPL director, is specifically choosing relatively low-time regional airline turboprop or jet first officers with no military training or experience with aerobatic flight.
“The idea is that if you do have aerobatic experience, you’re not too worried with the aircraft upside down. You roll to the nearest horizon,” says Schnell, an assistant professor and pilot who flies the L-29 and a variety of other aircraft and helicopters for OPL. Schnell does not plan to invert the pilots but will put them into attitudes and scenarios with bank and pitch angles that a typical regional pilot does not see in daily practice.
The subject pilot will fly in the rear seat behind two stacked 15.1-in. displays, the lower one representing a primary flight display and the upper showing a conformal 33-deg. lateral field of view of a virtual world outside that can be set to any location – a helpful option for scene texture, given the relatively flat landscape in eastern Iowa. The upper display can also be set to show head-up display symbology. The canopy is covered by a removable curtain on the inside, putting pilots in a simulated instrument-flight-rules environment and forcing them to rely on the instruments or misleading internal sensory information for situational awareness.
The pilots will fly scenarios with three versions of attitude information on the primary flight display; Classic “blue over brown” attitude graphics, a 12.8 deg. field of view synthetic vision attitude display (representing an Arinc size D display that would be found on an 8-in. primary flight display in commercial aircraft such as the Boeing 737NG), or a synthetic vision display with a 30-deg. field of view, similar to what is available on 15.1-in. primary flight displays in the Boeing 787 or coming in the 737 MAX.
One theory is that synthetic vision, which creates a daytime visual scene outside the aircraft regardless of the actual weather, will help pilots avoid losing attitude awareness. “It always happens in low visibility, at night or in fog; it never happens in daytime [visual meteorological conditions],” says Schnell of accidents caused by loss of spatial orientation.
The test will look at whether synthetic vision enhances attitude awareness and whether the width of the scene and optical flow cues (a terrain mesh, checkerboard pattern or speckling) boosts that awareness. Schnell says the wider scene should help by triggering the ganglion cell layers in the retina of the human eye, sensors that help orient humans in the horizontal direction based on peripheral vision.
Flights will last 90 minutes and include multiple examples of “sub-threshold” roll departures, post-roll illusions and other maneuvers. Pilots will be told to close their eyes and put their head down while the maneuver is being set up and will take control and recover when cued by the pilot. During a sub-threshold maneuver, turn rates are too low for the human vestibular system to pick up, which can lead to a very steep spiral if pilots follow their inner sense of motion rather than the aircraft’s instruments.
In a roll-reversal illusion, the front-seat pilot puts the aircraft in a turn in one direction and then rapidly reverses the roll, after which the subject pilot takes control and has to maintain final bank angle, despite an innate desire to reverse the roll. Steep spirals in instrument conditions are very dangerous, as the pilot’s natural reaction is to pull the control stick to exit the condition, an action that only steepens and tightens the corkscrew dive – hence the expression “graveyard” spiral.
TO BE CONTINUED
Stay up to date, follow us on Twitter; @LeadershipNGA