Virtual reality will make its way into commercial airliner flight decks in the next five years as part of a voluntary safety upgrade movement spurred by the government and industry Commercial Aviation Safety Team (CAST).
Synthetic vision, a 3-D rendering of runways, terrain and obstacles that gives pilots a sunny-day virtual view of the flight path ahead, is already standard fare for new general aviation and business jet cockpit displays and even for many portable devices, but it is not yet available in the cockpits of modern jetliners.
Along with an “optical flow” that artificially creates a sense of aircraft movement, synthetic vision systems (SVS) can also include energy awareness cues including a flight path vector, flight path acceleration and speed error indicator, aids safety advocates say can help eliminate attitude excursions that may lead to upsets and loss-of-control accidents.
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CAST, a grouping of FAA, airline and industry safety officials, originally came together in 1998 with the task of reducing the risk of having a fatal accident on U.S. commercial airliners by 80% by 2008, a goal it has largely met. CAST regrouped in 2011, with a new goal of cutting the commercial airline fatality rate by an additional 50% by 2020. Loss of control has by far been the largest underlying factor in fatal accidents since 2003.

Synthetic vision systems, widely available for the primary flight displays in business-jet cockpits, could soon be coming to airliner flight decks. Credit: Honeywell

As part of its work, the group analyzed 18 airline loss-of-control accidents or incidents in 2003-12 and determined that a “virtual-day” visual meteorological conditions (VMC) display, a.k.a. SVS, could have helped pilots avoid 17 of the 18 events where there were no external references to help orient the aircraft. Included in the loss-of-control list were the 2009 crashes of a Colgan Air Bombardier Q400 and Turkish Airlines Boeing 737-800, and the 2002 non-fatal loss-of-control incident involving an Icelandair Boeing 757-200.
In part because of the optical flow of the elements in a scene, SVS provides an intuitive sense of orientation, motion and ground closure rate compared to the legacy blue-over-brown attitude display. By adding energy guidance to an SVS display, CAST determined that the risk of a loss-of-control accident can be reduced by 16%, assuming 30% of the global airline fleet is equipped by 2035. If combined with 10 other interventions, the overall loss-of-control risk could be reduced by 73%.
However, SVS technology, first certified for transport-category aircraft by the FAA in 2006, has not yet made its way to airline cockpits, aside from a handful of aircraft with retrofit avionics upgrades. Although manufacturers are interested in the technology, there are concerns that by offering synthetic vision without a mandate or industry impetus, it could appear that they have ignored an essential safety tool that other sectors put in place years ago.
The CAST initiative solves that problem for the OEMs, as CAST recommendations have nearly the same clout as a mandate, with airframers generally agreeing to voluntarily implement the group’s recommendations—in this case, installing SVS in the form of a virtual-day VMC display in new aircraft by 2020.
Airbus, Boeing, Bombardier and Embraer have already committed to a separate CAST request to begin including the three energy-state cues into the primary flight display information on new-build aircraft by 2018. However, before implementing the virtual day-VMC display—also known as CAST Safety Enhancement 200—Boeing and Airbus have asked for more guidance on how to implement the recommendation and the certification risks of doing so, a request the FAA sent to its synthetic and enhanced vision working group under the auspices of RTCA Special Committee 213 (SC213).
SC213 primarily develops consensus-based general requirements, performance requirements and system performance verification guidelines for sensor-based systems or, with members representing a diverse group of regulators, including the FAA, European Aviation Safety Agency and Transport Canada as well as airframers and avionics providers. The standards generally become the basis for regulatory guidance or rules. The FAA asked the group to devise minimum system performance standards for the virtual-day VMC displays by June 2016, a date that may be overly optimistic.
During its first discussion of the task at a meeting in Paris in mid-April, the complexities of the request and the potential unintended consequences began to take shape. While simple in concept, the implementation of the virtual-day VMC display is far from settled.
A preliminary concept for the virtual-day VMC display includes a display of synthetic vision terrain and obstacles for all attitudes, a depiction of the runway of intended landing, and recovery guidance that could give a pilot visual or aural cues as to which way to roll or pitch the aircraft to bring the wings back to level attitude.
The virtual scene is to be available on the primary flight display at all times for both pilots.
Key elements to be determined through continued research and debate include how to show unusual attitudes and whether recovery cues should be included; how best to show and measure the optical flow of the scene; the required minimum display size, field of regard, compression ratio and resolution; and whether multiple colors should be used for the guidance. Also open for debate is whether the VMC display would be shown on head-up displays in aircraft equipped with the devices.
Intrinsic to the discussion is whether the SVS, currently certified as a situational awareness aid only, would require more scrutiny if it becomes the pilot’s primary tool to recovery from unusual attitudes. Today, regulators require or recommend that the flight guidance in an upset attitude revert to blue-over-brown with arrow cues showing the direction to recover. However, some SVS developers says leaving the synthetic scene in place for all attitudes will give the pilot better situational awareness cues, either preventing the upset in the first place or helping to speed the recovery.
This article was originally published on April 28.