Part of a report of a September near-miss between an Airbus passenger jet and a “helicopter drone” very close to Heathrow. (credit: UK Airprox Board)

File this under the category of “drone pilots trying to ruin it for everybody.” According to a safety incident report published by the United Kingdom’s Airprox air safety board, an Airbus A319 landing at Heathrow International Airport last September narrowly avoided a collision with a drone flying at an altitude of 500 feet as the jet was on its final approach. The pilots reported the small hovering helicopter-style drone passed about 25 yards to the left of the cockpit and just 20 feet above the aircraft.

The A319’s wingspan is 112 feet, so that would mean the drone missed the airliner by as little as 30 feet. The pilot reported that there was no time once the drone was sighted to take evasive action. The pilot reported the drone to air traffic controllers, and the police were dispatched. However, the drone pilot was not found. The incident was classified as meeting risk category A—the highest level of incident covered by the reporting system short of an actual collision.

The drone was not detected by air traffic control radar, so the only details of the event and how close the aircraft came to striking the drone are the pilot’s estimate of distance. In the UK, drones are limited to flight below 400 feet and are banned from flying in controlled airspace (like that around Heathrow) without permission from air traffic controllers. As the report noted, UK Civil Aviation Authority rules require a drone to stay within visual line of sight of the pilot—a maximum of 500 meters (1,640 feet) horizontally and 400 feet vertically from the operator.