Airbus A220 operators are being instructed to modify drain tubing after an incident in which rainwater dripped into the avionics bay and tripped a circuit breaker during taxi, causing an engine to shut down.
Rain had entered the aircraft through the main cabin entry door while it was open, according to Transport Canada.
This caused drains to overflow and led to dripping on the forward avionics bay below.
“Water ingress into the forward avionics bay could short-circuit the equipment in the area and lead to a loss of air-data sources,” says the regulator.
This might result in a reduction in function and an increase in the crew’s workload, it adds.
A220 operators are being ordered to modify the aircraft, within 12 months, by removing forward galley slotted drain covers, fitting solid blanking plates, and blocking drain tubing to prevent water travelling from the forward galley into the avionics bay.
All A220s are fitted with Pratt & Whitney PW1500G geared turbofan engines.