Confusing a Taxiway for a Runway - A Case for Synthetic Vision

On July 7 2017 just before midnight, Air Canada flight ACA759 began its approach to San Francisco International Airport (KSFO) runway 28R. Instead of lining up the runway the airplane was incorrectly lined up with the taxiway, where four passenger aircrafts were waiting for takeoff clearance. Thankfully, the pilot avoided collision at the last minute by initiating a go-around procedure by increasing altitude and circling around the airport before landing on the correct runway. Had the aircraft landed on the taxiway and collided with the parked jets, it would have been the deadliest incident in aviation history. The event been categorized as a near-miss and is currently being investigated by the National Transport Safety Board (NTSB).

For the past five years I have been working as a human factors specialist for Esterline CMC Electronics. One of the main projects I have contributed to is our SureSight synthetic vision system. Synthetic vision systems provide an intuitive picture of the aircraft position and orientation relative to airports, runways, tall buildings, terrain and water. It basically looks like you are flying a computer game.

CMC's synthetic vision system accomplishes this by drawing and artificial scene based input from a number of aircraft sensors. These sensors determine the orientation of the aircraft (pitch, heading, roll), position of the aircraft (altitude, latitude, and longitude) and combine this with a worldwide database of terrain, airports, runways and buildings to generate a synthetic scene. CMC's synthetic vision system also includes additional features such as runway highlighting which outlines the destination runway in a thick cyan border. This feature provides a clear indication to the pilot that they are flying to the correct runway. The end result is a live "out-the-window" view that is presented clearly regardless current visibility.

The image above is a snapshot of CMC's SureSight Synthetic Vision System taken at San Francisco airport. The image was generated by estimating the position of ACA759 61 m (200 ft) above the ground, aligned to the taxiway C. As is shown, the destination runway 28R is clearly left of the aircraft position and flight path. Even at a quick glance, it is obvious that the aircraft isn't lined up to runway 28R. Despite this, the flight crew of ACA759 continued its descent below 30 m (98 ft) above ground before realizing they realized their grave error, narrowly avoiding the tails of the parked airplanes. Thankfully, the pilot pulled up and returned to land safely however I can't help wonder whether the ACA759 would have been in this situation if the aircraft had been equipped with synthetic vision.

If you would like to read more about the ACA759 investigation I have provided a link below.

NTSB Investigation DCA17IA148

About Me:

Patrick Bickerton is a Human Factors Design Specialist for Esterline | CMC Electronics and is an Affiliate Human Factors Processional (AFHP) with the Boards of Certified Professional Ergonomists (BCPE). Patrick has a range of education and experiences in the domains of human factors, cognitive science, statistics, ergonomics and industrial design that has allowed him to collaborate in design and development of human systems.