Definition

A synthetic vision system (SVS) is an aircraft installation that combines three-dimensional data into intuitive displays to provide improved situational awareness to flight crews. This improved situational awareness can be expected from SVS regardless of weather or time of day. In addition the system facilitates a reduced pilot workload during complex situations and operationally demanding phases of flight, e.g. on approach. SVS merges a high resolution display(s) with databases of terrain and obstacle data, aeronautical information, data feeds from other aircraft, and GPS to show pilots where they are and what is in their immediate surrounding area. SVS displays a model of the real world, presenting information to the flight crew in a way that is easy to understand and rapidly assimilated. The picture presented on the SVS display(s) replaces conventional sky and ground depiction to include a 3D representation of the external environment with details of terrain, obstacles, weather, the approach path, runway and aerodrome manoeuvring areas, and other traffic.

Discussion

SVSs have been developed for improving aircrew situational awareness, particularly during the approach and landing phase of flight. They are also very effective in improving flight safety, specifically with regard to reducing the incidence of controlled flight into terrain (CFIT) events. SVS operations can also represent a flight safety challenge due to potential flight crews’ overreliance on the SVS to the detriment of other references necessary for safe navigation or due to the utilization of SVSs by un-qualified crews. From a technical point of view, an SVS installed in an aircraft must meet the minimum safety performance standards documented for SVS in RTCA DO-315B/Eurocae ED-179B. In the domain of flight operations, training represents the main defence for operators to prevent the misuse or non-standard use of SVSs by flight crews. A flight crew must undergo training on SVS operation as part of the rating on their aircraft type and meet any applicable currency requirement to be qualified for SVS operations. From a technical perspective, unless redundancy is built in, pilots can quickly lose situational awareness should there be a malfunction in the SVS unless they are trained to rely on other cockpit information available. Another concern is incorrect or corrupted data, and the SVS must have strict currency and validation criteria as well as reliable reception of transmitted data. As a result of the adoption of SVS primary flight displays, the operator must ensure that the phenomenon of attention tunnelling or capture is given appropriate or increased emphasis during training to make flight crews aware that they can become overly focussed on the SVS display to the exclusion of other references or information inside and outside the aircraft.

Related Articles

• Enhanced Vision System
• Controlled Flight Into Terrain (CFIT)
• Situational Awareness

Further Reading

• DO-315B Minimum Aviation System Performance Standards (MASPS) for Enhanced Vision Systems, Synthetic Vision Systems, Combined Vision Systems and Enhanced Flight Vision Systems, EUROCAE, Dec 2008 - This document addresses Enhanced Vision Systems (EVS), Synthetic Vision Systems (SVS) and Combined Vision Systems (CVS) technologies. It adds system design criteria for use of SVS for lower-than-standard Category I ILS minima. Specific features include SVS with system performance, database, alerts, pilot controls, display and symbology requirements.
• FAA Advisory Circular No 20-167A: Airworthiness Approval of Enhanced Vision System, Synthetic Vision System, Combined Vision System, and Enhanced Flight Vision System Equipment, December 2016
• EUROCONTROL Terrain and Obstacle Data Manual, November 2015