It’s natural for people to trust physical sensations. We feel them when an elevator is moving down floors or when there are changes in pressure at higher elevations. In some cases, however, what our bodies are feeling can be misleading. For pilots, this can occur during what is called spatial disorientation, and it can be deadly.
Spatial disorientation is a factor in roughly 10 percent of loss-of-control events, which are the leading cause of fatal accidents in commercial aircraft. Ninety percent of crashes resulting from spatial disorientation scenarios are fatal.
Previously, exposing pilots to the feeling of spatial disorientation in standard flight simulator training has had limited effectiveness, especially for fatal scenarios. To address this, the Federal Aviation Administration (FAA) provided funding through the Small Business Innovation Research (SBIR) program to Systems Technology Inc. (STI) to develop technology that could be used with current simulation equipment to train pilots to recognize and react to spatial disorientation events in flight.
The work began as a Phase I proof-of-concept in 2012 followed by a Phase II award in 2014, which funded the development of a working prototype.
Riding the Teacups: Teaching Pilots to Trust Their Instruments
There are two varieties of spatial disorientation: visual and vestibular. STI focused on vestibular illusions, which affect the human body’s internal motion sensors, including the inner ear.
“The inner ear is basically the human gyroscope,” said David Klyde, vice president and technical director of Engineering Services at STI. “We’re made to wander around the earth in a 1 g-force environment. When you move into 3-D space, your system is not always able to properly recognize the motions. It’s a sensation similar to riding the teacups at an amusement park: occasionally you get off the ride and still feel like you’re spinning, even though you’re not. Pilots need to learn to always trust their instruments and not their physiological sensations.”
Overcoming Simulator Limitations
Existing flight motion simulators used in commercial airline pilot training have a limited range of motion and are not designed to produce the sustained acceleration and rate needed to replicate the feeling of spatial disorientation. STI’s team spent two weeks at the National Aeronautics and Space Administration’s (NASA) Ames Research Center to develop solutions to overcome these limitations.
They came up with a motion system software update that can demonstrate the sensations of the two most common spatial disorientation scenarios: a pitching-up sensation associated with a missed approach and a post-roll turning sensation associated with a long-duration steady turn. With no discernible horizon outside of the window, the operator is forced to rely on the cockpit displays instead of the physical sensations.
“The pitching illusion that a pilot feels when accelerating forwards has been implicated as a possible cause in several accidents worldwide. The French National Transportation Safety Board recommended that the International Civil Aviation Organization study whether simulators could satisfactorily replicate this illusion,” said Dr. Jeffery Schroeder, FAA’s chief scientist for flight simulation. “Frankly, prior to this project, I was skeptical whether much could be done. However, the results look promising. We had two major simulator manufacturers visit during the experiment, and I think it also gave them food for thought.”
STI’s Phase II SBIR project ended in February with the finalization of its software and piloted simulation results.
“We’ve learned the process and have really taken to heart the commercialization aspect of it,” Klyde said.
The next step is to work with manufacturers and airlines to introduce the product into standard commercial pilot trainings.
With STI’s work now crossing over to U.S. DOT, pilots will soon have more training opportunities ahead of them, leading to safer skies for everyone.