Flight Details
Aircraft Type: Airbus A321-211 Operator: Air Canada Rouge Registration: C-FJQL Flight Number: RV1702 / AC1702 Route: Harry Reid International Airport (LAS), Las Vegas, NV to Toronto Pearson International Airport (YYZ), Ontario, Canada Date of Incident: 16 April 2025 Total Occupants: 176 (passengers and crew) Weather Conditions: Enroute cruise at FL350; no convective activity or turbulence reported
Introduction
On 16 April 2025, an Airbus A321 operated by Air Canada Rouge was forced to divert to Des Moines International Airport (DSM) after the flight crew detected an acrid electrical burning odour accompanied by abnormal vibrations and noise beneath the flight deck floor. The aircraft had been cruising at FL350, approximately 30 nautical miles north of Des Moines, Iowa, when the crew declared a PAN PAN urgency call, requested descent to 10,000 feet, and diverted.
The aircraft landed safely on runway 13 within 17 minutes of the initial decision to divert. Airport Rescue and Firefighting (ARFF) teams were placed on standby but found no visual abnormalities upon arrival. The aircraft was taxied to the gate under its own power. The Canadian Transportation Safety Board (TSB) is now investigating.
Sequence of Events
Flight RV1702 had departed Las Vegas for Toronto and was nearing the midwestern segment of its route when the flight crew began experiencing abnormal sensations from the lower avionics bay, located beneath the cockpit floor. These sensations included:
Noticeable vibration A loud, abnormal mechanical noise An increasingly strong odour of electrical burning
The flight crew immediately began ECAM checklist procedures and declared PAN PAN—an urgency message indicating a situation that is not yet an emergency but requires immediate attention.
During descent, the aircraft triggered an ECAM alert for the avionics ventilation blower extract system, a critical component responsible for managing heat generated by electrical systems in the forward equipment bay.
Key flight deck actions included:
Initiation of descent to breathable altitude (FL100) Execution of ECAM Avionics Vent Blower Extract checklist Coordination with Minneapolis Center and DSM approach controllers Briefing of cabin crew and preparation for precautionary landing
At no point was smoke visible in the cabin or cockpit. However, the strength of the odour and the nature of the vibration prompted the crew to treat the situation as potentially escalating.
The aircraft landed without incident and was met by emergency vehicles. Following external inspection and confirmation of no immediate hazard, the aircraft was cleared to taxi to the gate.
Crew & Communication
The flight crew demonstrated proactive and procedural handling of the situation, including:
Use of PAN PAN urgency call instead of MAYDAY, reflecting a controlled but developing scenario Systematic execution of Airbus ECAM-driven response protocols Effective CRM between pilots and communication with cabin crew Timely briefing of passengers without causing panic
The cabin crew remained in full control, advising passengers and securing the cabin for descent and possible evacuation. Passengers were not informed of any visible threat, and there are no reports of panic or distress onboard.
Aircraft Systems & Technical Analysis
The Airbus A321 uses an avionics ventilation system that incorporates:
An extract fan Inlet and outlet valves Heat exchangers Temperature and differential pressure sensors Airflow from cabin and equipment bay
The Avionics Vent Blower Extract ECAM warning typically signifies:
Blower fan failure or seizing Electrical motor overheating Exhaust blockage or degraded filter flow Ventilation temperature rising beyond acceptable limits
The vibrations and abnormal noise reported by the crew likely stemmed from:
Fan imbalance or bearing failure Debris ingestion into the ventilation ductwork Motor overload causing electrical arcing and odour
The electrical burning odour is consistent with insulation breakdown or component overheat in the extract fan motor assembly or control unit.
Given that the aircraft returned to service more than 43 hours after landing, it is likely that engineers:
Removed and replaced the ventilation fan assembly Conducted avionics bay inspections for signs of heat or charring Performed wiring continuity checks and functional fan tests Ensured the cabin environmental control system was unaffected
Passenger Experience & Cabin Conditions
The event was primarily contained to the cockpit and forward avionics bay. No visible smoke or cabin anomalies were reported by passengers.
Cabin pressure, lighting, and environmental systems functioned normally throughout. The cabin crew provided clear communication, and no injuries were reported.
Passengers were disembarked at Des Moines and re-accommodated by the airline. A replacement A321 (registration C-GKFB) was dispatched and reached Toronto with an overall delay of approximately eight hours.
Emergency Response & Aftermath
ARFF units staged along runway 13 and conducted a visual thermal inspection of the aircraft upon arrival. No external anomalies were detected, and no extinguishing agents were required.
Post-landing activities included:
Gate positioning and external ground power connection Engineering log review and crew debrief Inspection of avionics bay and fan housing
No fuel leaks, smoke residue, or component detachment were identified.
Investigation Status
The Transportation Safety Board of Canada (TSB) confirmed involvement on 22 April 2025. Initial statements from the TSB indicate:
The incident involved electrical component degradation There were no active flames or smoke The crew’s handling of the situation adhered to manufacturer and regulatory guidance
As per protocol, Airbus and Transport Canada may be informed for fleet-wide awareness if systemic faults are identified.
Root Cause & Contributing Factors
The root cause is preliminarily attributed to:
Mechanical failure of the avionics extract fan Electrical arcing or overheating of ventilation motor Potential sensor failure allowing delayed ECAM alert
Contributing factors could include:
Dust or debris ingestion from cabin air recirculation systems Wear-and-tear in fan motor bearings Environmental factors such as low humidity or prior maintenance exposure
Safety Recommendations & Industry Impact
If confirmed, the incident may result in:
A fleet-wide inspection directive (SB or AD) for Airbus A321 avionics fans Enhanced monitoring of ventilation system noise or odour anomalies during cruise Additional training for flight crew on early warning indicators of extract system failure Review of maintenance intervals for high-time fan components
This incident also highlights the importance of clear PAN PAN communication, where time-critical but non-emergency events can be addressed without overstating severity.
Conclusion
Air Canada Rouge flight RV1702’s diversion to Des Moines due to an electrical odour and ventilation system failure was a textbook case of early detection, decisive CRM, and controlled handling. Though no injuries or damage occurred, the incident serves as a reminder of the critical role that auxiliary systems—like avionics ventilation—play in safe long-haul operations.
The TSB investigation will determine whether deeper systemic issues require manufacturer or operator response.
Disclaimer
This article is based on publicly available information and reports at the time of writing. While every effort has been made to ensure accuracy, we cannot guarantee the completeness of the information provided.
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