Airbus A220 operators are being instructed to check and replace emergency locator transmitter antennas, after incidents in which vortices from a communications radome generated vibrations resulting in antenna failure.
One of the incidents resulted in the antenna separating from the aircraft and striking the vertical fin.
Investigations have traced the problem to vibration loads caused by vortices forming around the radome of the Gogo 2Ku satcom system, mounted atop the fuselage, which provides satellite connectivity for in-flight internet and other services.
Transport Canada says the situation could not only lead to loss of the locator transmitter antenna but also potential cracking in the fuselage, which could result in reduction of cabin pressure.
It has instructed operators to replace the locator antenna with a new one at specified intervals, depending on flight time, and carry out repetitive inspection of the fuselage skin around the attachment area for damage. Locator antennas which have accumulated over 3,500h need to be replaced within 200h.
Both the A220-100 and A220-300 are covered by the Transport Canada directive.