Transport Canada (TC) revised an Airworthiness Directive (AD) to prevent engine shutdowns on the Airbus A220. The regulator traced back the reason for the shutdowns to be water ingress on the forward avionics bay, which could cause a short circuit.
Originally, Transport Canada (TC) identified the issue much earlier. The original AD to cover the problem of water dripping down on the forward avionics bay was addressed on September 18, 2020. The AD CF-2020-30 was posted following an Airbus A220 engine shutting down during taxiing. The authority did not specify the date and location of the engine shutdown.
The problem was caused due to rain entering the cabin through the main entry door while it was open, highlighted the Canadian regulator. The rain caused drains to overflow and the water dripped to the forward avionics bay.
“Water ingress into the forward avionics bay could short circuit the equipment in the area and lead to a loss of air data sources resulting in a reduction in functional capabilities, and an increase in crew workload,” read the AD.
To prevent rain water from entering the avionics bay, the regulator ordered Airbus A220 operators to install blanking plates on drains, replacing slotted drain covers, in addition to blocking off “the associated drain tubing” in the forward galley. Airbus Canada Service Bulletin (SB) BD500-530009, issued on July 31, 2020, specifies the actions needed to rectify the problem in more detail, noted the Canadian regulator.
The effective date of the initial AD was September 18, 2020, and Airbus A220 operators had 12 months to complete the actions necessary to safely operate the aircraft starting with that date. The AD affected all A220-100 and A220-300 serial numbers 50001 and 55001, respectively.
On December 14, 2020, TC revised the AD, as some operators completed the changes to the aircraft, formerly known as the Bombardier CSeries. Now, the directive is applicable to A220-100s serial numbers 50001 through 50018 and 5020 through 50055. For A220-300 models, the serial number applicability is 55001 through 55016, 55018 through 55068, 55070 through 55083, 55086 through 55088 and 55090, indicated TC.