Eurocontrol is alerting aviation authorities worldwide of potential new collision threats due to ships that have begun experimenting with large high-flying kites or sails for auxiliary propulsion.

The action comes after a 15 September incident in which an aircraft descending over the southern North Sea reported seeing a kite or sail flying at approximately 305m (1,000ft) height "just below the clouds" ahead of a ship as it headed into port. Eurocontrol has not revealed the type or operation of the aircraft involved.

skysail

 Skysail concept - Eurocontrol

"It was attached to the vessel and was in the flight path of the aircraft as it headed towards a nearby installation," the agency reports in a safety warning message issued today. "The 'skysail' was extended on a long cable and was moving around the vessel in an erratic manner."

Officials later determined that the ship in question is "the first in a line of experimental vessels using skysails to supplement the traditional propulsion units".

Source: Air Transport Intelligence news