Date: 27th November 2024
Location: Montreal Mirabel International Airport, Quebec, Canada
Aircraft: Boeing 737-400, registration C-GGWX
Operator: Nolinor Aviation
Flight Number: N5-662
Route: Quebec City, QC, to La Baie, QC, Canada
Occupants: 87 (81 passengers, 6 crew)
Injuries: None reported
Summary of Events
On 27th November 2024, Nolinor Aviation flight N5-662, a Boeing 737-400, encountered a landing gear malfunction while en route from Quebec City to La Baie. During the approach to La Baie, the crew received an unsafe gear indication and initiated a go-around. Unable to resolve the issue, the flight was diverted to Montreal Mirabel, where the aircraft performed an emergency landing with the left main gear not fully extended.
The aircraft landed on Runway 24 and came to a halt on the runway. Emergency services responded promptly, and all 87 occupants evacuated safely without injuries.
Aircraft Information
The Boeing 737-400 is a twin-engine narrow-body aircraft widely used for short to medium-haul routes. The aircraft’s landing gear is hydraulically actuated, with redundancy built into the system to prevent failures. However, mechanical malfunctions or hydraulic issues can result in partial or complete gear retraction failures.
Sequence of Events
1. Approach to La Baie:
• While on final approach to La Baie’s runway, the crew received an unsafe gear indication for the left main landing gear.
• A go-around was initiated, and troubleshooting procedures were performed, including manual extension of the landing gear.
2. Decision to Divert:
• Unable to confirm the full extension of the left main gear, the crew opted to divert to Montreal Mirabel, which has better facilities and emergency support.
3. Landing at Mirabel:
• The aircraft performed a controlled landing on Runway 24 with the left main gear not fully extended.
• The aircraft came to rest on the runway, with the left wingtip and engine nacelle making contact with the surface.
4. Evacuation:
• All 87 occupants safely evacuated the aircraft via emergency slides.
• No injuries were reported among passengers or crew.
Initial Findings
Landing Gear Malfunction
The preliminary inspection revealed that the left main gear did not lock into place during deployment. This could be attributed to:
• A mechanical failure within the gear locking mechanism.
• Hydraulic pressure loss or obstruction.
Emergency Response
The crew’s decision to divert to Montreal Mirabel and their execution of a controlled landing ensured the safety of all occupants. Emergency services responded promptly, securing the scene and assisting in the evacuation.
Investigation
The Canadian Transportation Safety Board (TSB) dispatched investigators to Mirabel to examine the incident. The scope of the investigation includes:
1. Mechanical and Hydraulic Systems:
• Examination of the landing gear assembly and hydraulic actuators.
• Analysis of maintenance records for any prior issues with the gear system.
2. Crew Actions:
• Review of cockpit voice and flight data recorders (CVR and FDR) to evaluate crew decision-making and compliance with procedures.
3. Aircraft Performance:
• Assessment of the aircraft’s behaviour during the landing sequence, including speed, attitude, and descent rate.
Safety Risks
1. Landing Gear Failures:
• A malfunctioning landing gear poses a significant risk during landing operations, particularly on wet or contaminated runways.
2. Structural Damage:
• The contact of the left engine nacelle and wingtip with the runway could lead to substantial repair costs and operational downtime.
3. Evacuation Challenges:
• In such scenarios, rapid and safe evacuation is critical to prevent injuries, especially in the presence of fuel leaks or fire hazards.
Recommendations
1. Enhanced Maintenance Protocols:
• Introduce more rigorous inspections of landing gear systems, focusing on locking mechanisms and hydraulic actuators.
2. Training for Similar Scenarios:
• Reinforce crew training for handling gear-related emergencies, including decision-making for diversions and emergency landings.
3. Technical Modifications:
• Explore potential design improvements in landing gear systems to reduce the likelihood of mechanical or hydraulic failures.
4. Regulatory Oversight:
• Conduct regular audits of operator compliance with maintenance and operational safety standards.
Safety Lessons
This incident highlights the importance of rigorous pre-flight checks and proactive maintenance of critical aircraft systems. The professional actions of the flight crew ensured a safe outcome, demonstrating the value of emergency training and adherence to procedures.
Disclaimer
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Our investigation reports are based on all the evidence and facts we have at the time of writing and posting. We apologise if any details are missed or are not fully accurate.
