Date: 26th November 2024
Location: Quebec City Airport (YQB), Quebec, Canada
Aircraft: Boeing 737-400, registration C-GGWX
Operator: Nolinor Aviation
Flight Number: N5-661
Route: Wabush, NL (Canada) to Bagotville, QC (Canada)
Occupants: 113 passengers and 7 crew
Injuries: None
Summary of Events
On 26th November 2024, Nolinor Flight N5-661, a Boeing 737-400, encountered a significant flaps discrepancy while diverting to Quebec City due to adverse weather conditions at its destination, Bagotville. During final approach to Quebec City’s Runway 06, the flight crew observed a mismatch in flap positions, with the left-hand flaps indicating 25 degrees and the right-hand flaps only 14 degrees. This asymmetry caused the aircraft to drift to the right.
The crew declared an emergency, aborted the approach, and executed the appropriate checklists. They subsequently landed safely on Runway 06 approximately 13 minutes after the go-around. No injuries were reported among the passengers or crew.
Sequence of Events
1. Weather Diversion:
• Due to adverse weather at Bagotville, the flight was rerouted to Quebec City (YQB).
2. Final Approach and Flaps Issue:
• During the LPV (Localizer Performance with Vertical Guidance) approach to Runway 06, the flight crew noticed a discrepancy in flap extension between the left and right flaps.
3. Emergency Declaration:
• Observing the asymmetry and its impact on aircraft handling, the crew declared an emergency and initiated a go-around.
4. Checklist Procedures:
• The crew worked through the relevant emergency checklists to address the flaps issue.
5. Safe Landing:
• The aircraft returned for a second approach and landed safely on Runway 06 without further complications. Emergency services were on standby but were not required.
Aircraft Details
• Type: Boeing 737-400
• Registration: C-GGWX
• Configuration: Passenger aircraft
Initial Findings
1. Flap Asymmetry:
• The left flaps extended to 25 degrees, while the right flaps extended to only 14 degrees, creating an asymmetrical configuration that affected the aircraft’s controllability.
2. Crew Response:
• The flight crew promptly identified the issue, declared an emergency, and executed procedures to mitigate the risk.
3. Weather and Operational Factors:
• The diversion was necessitated by adverse weather at the original destination, potentially contributing to operational stress and complexity.
Impact on Subsequent Operations
• The aircraft was removed from service for inspection and maintenance following the incident.
• The same aircraft experienced another significant issue the following day, resulting in an accident at Montreal (see related report: “Accident: Nolinor B734 at Montreal on Nov 27th 2024, flaps problem, gear collapse”).
Recommendations
1. Inspection and Maintenance:
• Conduct a thorough inspection of the flap system, focusing on mechanical linkages, hydraulic actuators, and control sensors, to identify the root cause of the asymmetry.
2. Crew Training:
• Reinforce training on handling flap asymmetry scenarios and related emergency procedures.
3. Operational Coordination:
• Enhance communication protocols between operations control and flight crews during weather-related diversions to minimize stress and decision-making pressure.
Safety Lessons
This event highlights the importance of robust maintenance procedures and crew preparedness in managing unexpected technical issues. The prompt actions of the flight crew ensured a safe outcome despite a potentially hazardous situation.
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