On October 25, 2024, a Jazz Canadair CRJ-900, registration C-GLJZ, encountered a series of airspeed-related anomalies while enroute from Toronto, ON (Canada) to Minneapolis, MN (USA). Operating as flight QK-721, the aircraft was cruising at FL360 when the captain’s airspeed indicator malfunctioned, leading to a cascade of automated system responses, including the activation of the stick shaker and autopilot disconnection. Despite these critical in-flight challenges, the flight crew skillfully managed the situation, declared a PAN PAN emergency, and landed the aircraft safely at Minneapolis’ runway 30R.
Incident Summary
• Aircraft Model: Canadair CRJ-900
• Registration: C-GLJZ
• Flight Number: QK-721
• Route: Toronto Pearson International Airport (YYZ), Canada, to Minneapolis-Saint Paul International Airport (MSP), USA
• Incident Location: Approximately 90 nautical miles east of Minneapolis at FL360
• Date and Time: October 25, 2024
The aircraft’s captain experienced a sudden loss of reliable airspeed information on the primary flight display. Simultaneously, low and high-speed cues appeared, signaling potentially dangerous airspeed conditions. As a result, the stick shaker activated on the captain’s side to warn of an impending stall, and the autopilot disconnected, transferring full control back to the flight crew. Notably, the airspeed indications on the first officer’s side and the standby airspeed system remained functional and showed normal readings.
In-Flight Complications and Crew Response
The crew encountered multiple warnings and system failures, prompting them to execute a series of emergency checklists and procedures:
1. Unreliable Airspeed Indications: The captain’s airspeed indicator malfunctioned, causing the autopilot to disconnect. This required the flight crew to manually control the aircraft, relying on the first officer’s and standby instruments for accurate airspeed data.
2. Stick Shaker Activation: The stick shaker, which vibrates the control yoke to warn of an imminent aerodynamic stall, activated on the captain’s side. This indicated that the system believed the aircraft was at risk of stalling, even though the actual airspeed on the first officer’s side was normal.
3. Stall Fail Message: During the descent toward Minneapolis, the crew also received a stall fail message, indicating a malfunction in the stall warning system. This message implied that the system might not be able to provide accurate stall warnings, further complicating the flight crew’s situational awareness.
4. Emergency Declaration: Given the complexity of the situation and the need for immediate attention, the crew declared a PAN PAN emergency, indicating an urgent but non-life-threatening situation. This ensured priority handling by air traffic control.
Crew Actions and Emergency Procedures
The flight crew acted swiftly and decisively in response to the multiple failures:
• Manual Aircraft Control: With the autopilot disconnected, the crew manually flew the aircraft, carefully managing the descent and monitoring the working airspeed indicators.
• Checklist Execution: The crew followed the unreliable airspeed checklist, which included cross-checking airspeed indications and stabilizing the aircraft’s attitude to maintain safe flight parameters.
• Descent and Approach: During the descent, the crew managed airspeed and altitude carefully, ensuring the aircraft remained stable. They prepared for a landing on runway 30R at Minneapolis-Saint Paul International Airport.
The crew’s effective management of the situation prevented the incident from escalating, and the aircraft landed safely without further complications. The Canadian Transportation Safety Board (TSB) later reported that there was no significant reaction from passengers, indicating a smooth and controlled descent and landing.
Technical Analysis: Unreliable Airspeed and Stick Shaker Activation
Airspeed anomalies in modern aircraft like the CRJ-900 are often linked to issues with the pitot-static system, which provides critical airspeed, altitude, and vertical speed data to the flight instruments. Here’s a detailed look at the potential causes:
1. Pitot-Static System Malfunctions
The pitot tubes and static ports on an aircraft measure dynamic and static air pressure, converting these readings into airspeed and altitude information. Contamination, such as ice or debris, can lead to erroneous readings. In this case, a blockage or fault may have caused the captain’s airspeed indicator to fail.
• Pitot Tube Icing: Although most modern aircraft, including the CRJ-900, are equipped with pitot heat to prevent icing, failures can still occur if the heating system malfunctions.
• Static Port Blockage: Similar issues can occur if static ports become obstructed, although this incident primarily involved the pitot system.
2. Automated System Responses
The CRJ-900’s avionics are designed to respond automatically to airspeed discrepancies:
• Stick Shaker Activation: The stick shaker is part of the aircraft’s stall protection system. It activates when the aircraft approaches a critical angle of attack, warning the pilots of a potential stall. In this case, it activated incorrectly due to the faulty airspeed data.
• Autopilot Disconnection: The autopilot disengages automatically when it detects unreliable airspeed or other critical system failures, transferring control to the pilots.
3. Stall Warning System Failure
The stall warning system, which typically uses inputs from angle-of-attack sensors and airspeed indicators, failed to operate correctly, as indicated by the stall fail message. This likely added complexity to the crew’s management of the situation, as they had to rely solely on visual and manual cues to maintain safe flight.
Post-Incident Actions and Aircraft Return to Service
After safely landing, the aircraft underwent a thorough inspection by maintenance crews to identify and rectify the underlying issues. The aircraft remained on the ground for about 12.5 hours before returning to service, suggesting that the problem was diagnosed and addressed relatively efficiently.
Maintenance and Inspection Focus Areas:
1. Pitot-Static System Inspection: Engineers would have examined the pitot tubes and static ports for blockages, damage, or malfunctioning heating elements.
2. Stall Protection System Check: The stall warning and stick shaker systems would have been tested to ensure they were functioning correctly.
3. Avionics and Data Systems Review: A comprehensive check of the aircraft’s avionics was likely conducted to ensure all systems provided accurate and reliable data.
Implications for Aviation Safety
This incident highlights the importance of redundancy and crew training in managing in-flight anomalies. Modern aircraft are equipped with multiple systems to cross-verify critical flight information, allowing crews to identify and respond to unreliable data. The crew’s ability to manage the situation effectively demonstrates the value of rigorous training and adherence to emergency checklists.
Key Takeaways:
• Importance of Redundancy: The availability of reliable airspeed information from the first officer’s and standby instruments was crucial in maintaining safe flight.
• Crew Proficiency: The pilots’ quick and coordinated response ensured passenger safety, showcasing the importance of ongoing training for handling complex scenarios.
• Preventive Maintenance: Regular checks of the pitot-static system and stall protection systems are essential to prevent similar incidents.
Conclusion
The Jazz CRJ-900 incident on October 25, 2024, underscores the challenges posed by unreliable airspeed readings and automated system responses. The crew’s well-executed emergency procedures and the aircraft’s redundancy systems played vital roles in ensuring a safe outcome. While the aircraft returned to service relatively quickly, the incident serves as a reminder of the critical need for system reliability and the effectiveness of well-trained crews in managing emergencies.
Disclaimer
This analysis is based on the best available information and post-incident reports. Details may be updated as further findings are released by Jazz Aviation or aviation authorities. We apologize if any information is incomplete or subject to changes.
