A potentially terrifying situation unfolded on an Air Canada Rouge flight bound for Toronto earlier this month when oxygen masks were deployed after the crew reported an "abnormal noise" on the aircraft.

The Air Canada Rouge Airbus A321-200, operating as flight RV-1645, took off from Miami International Airport at approximately 1:20 p.m. on Saturday, May 18, with 189 passengers on board. 

According to the Aviation Herald, the aircraft, bound for Toronto Pearson International Airport, was flying near Pittsburg, Pennsylvania, when the crew heard a strange noise followed by vibrations and an odour of the flight deck. 

Although the crew donned their oxygen masks as a precaution, no Electronic Centralized Aircraft Monitor (ECAM) or abnormal indications occurred. 

After unsuccessful troubleshooting, the Aviation Herald says the flight crew declared PAN-PAN — an international radio distress signal, which is of less urgency than a mayday signal and is used to communicate an urgent, but non-emergency situation to air traffic control. 

This signal might involve an aircraft requiring rerouting or landing at a nearby airport, with the flight crew being able to handle the issue assisted with priority from air traffic control. 

#EMERGENCY | On May 18, an Air Canada Rouge Airbus A321 from Miami made an emergency landing into it's destination of Toronto.

Read more at AviationSource!https://t.co/ljZCDt52Qa@RadarBoxCom#AirCanadaRouge #Miami #Toronto #AvGeek pic.twitter.com/P7tDfbJJYI

— AviationSource (@AvSourceNews) May 25, 2024

On the other hand, Mayday communication is urgent and requires remediation attention to an issue threatening the lives of those onboard the aircraft. 

Luckily, the aircraft continued to Toronto Pearson International Airport for a safe landing at 4:11 p.m. and taxied to the apron without any injuries. 

The Transportation Safety Board of Canada (TSB) reported that maintenance found the avionics blower fan of the aircraft to be defective, and the component was replaced.