Two planes came into close contact while flying over Kelowna, back in January of 2019.
A WestJet flight heading from Calgary to Nanaimo encountered a ‘loss of separation’ with a private plane bound for Kamloops on Jan. 3, 2019, warranting an investigation by the Transportation Board of Canada (TSB).
The investigation revealed that an error in-flight data, along with other factors resulted in the two planes coming into close contact or a loss of separation. A vertical separation of 1000 feet is required between planes, however, in this instance, the separation distance was not maintained.
According to the report, the flight data processors in Vancouver had undergone a software update before the incident, during the update previous information had not been purged, leading to a discrepancy error between the flight plan data and the radar flight path of the private plane.
The controller wasn’t familiar with such errors and in his attempt to resolve the issue he did not identify the potential conflict between the Westjet plane and private plane’s flight plans.
The error meant the software designed to predict traffic conflicts, which the controller relied on, was unavailable to predict the loss of distance separation. At the time traffic volume in the airspace had also increased, leading to a greater workload for the controller.
According to the TSB, the controller did not see or hear the visual and audible warnings as the two aircrafts approached each another.
Fortunately, the traffic alert and collision avoidance system (TCAS) on board the WestJet Encore flight warned the crew to decrease altitude, stated the TSB.
Following this incident, Navigation Canada implemented a number of safety actions including making improvements to the checklist for completing software updates and purging flight data from the system.