Date: 16th April 2023
Location: Sault Ste. Marie Airport, Ontario, Canada
Aircraft: De Havilland Dash 8-400, registration C-GLQB
Flight Number: PD-2691
Operator: Porter Airlines
Flight Route: Toronto City (Ontario) to Sault Ste. Marie (Ontario)
Passengers: 52
Crew: 4
Summary of Events
On 16th April 2023, Porter Airlines Flight PD-2691, a De Havilland Dash 8-400, overran Runway 12 at Sault Ste. Marie Airport during its landing roll at 22:21 local time. The aircraft came to a stop approximately 85 meters (280 feet) beyond the runway threshold on soft ground. There were no injuries, and the aircraft sustained minor, if any, damage.
The runway was closed for approximately 15 hours following the incident, and passengers were transported to the terminal using airport limousines. On 20th November 2024, the Transportation Safety Board of Canada (TSB) released its final report on the incident, citing delayed braking action, degraded runway surface conditions, and technical system factors as the primary contributors to the overrun.
Aircraft and Crew Information
The aircraft, registration C-GLQB, was a De Havilland Dash 8-400 (Q400), a twin-engine turboprop designed for short-haul operations. Porter Airlines uses the Q400 extensively for its regional network.
The flight crew included an experienced captain and first officer, both trained to operate the Q400 in challenging conditions. However, their situational awareness during the landing roll and delayed responses to critical cues were identified as factors contributing to the incident.
Sequence of Events
1. Approach and Landing:
• The aircraft conducted an RNAV approach to Runway 12 at night in light rain.
• The flight crew planned to touch down between 1,000 and 2,000 feet from the runway threshold, with Taxiway J marking the target landing zone.
2. Touchdown:
• The aircraft initially touched down softly, delaying the deployment of the wing spoilers.
• Solid touchdown occurred 2 seconds later, approximately 2,850 feet down the 6,000-foot runway.
3. Deceleration Issues:
• The first officer applied light braking as per company procedures but did not immediately recognize the proximity to the runway end.
• The captain took over braking approximately 850 feet from the runway end, applying maximum braking.
4. Overrun:
• The aircraft overran the runway end at a ground speed of 78 knots and came to rest on soft ground approximately 85 meters (280 feet) beyond the runway threshold.
Key Findings
1. Runway Situational Awareness
• The flight crew misjudged their position on the runway due to limited visual cues during the night landing.
• Taxiway J, which marked the end of their planned landing zone, was likely mistaken for the intersection of Runway 04/22, leading to an inaccurate mental model of their position.
2. Delayed Braking Action
• Full braking was not applied until 850 feet from the runway end, leaving insufficient distance for the aircraft to stop.
• The delayed braking action was influenced by the captain’s focus on lateral alignment rather than deceleration immediately after touchdown.
3. Technical System Issues
• Air contamination in the hydraulic system was identified during post-incident maintenance, potentially degrading braking performance.
• The wing spoilers deployed late due to the soft touchdown, reducing aerodynamic braking during the initial landing roll.
4. Runway Surface Conditions
• The surface microtexture and macrotexture of the last 300 feet of Runway 12 were degraded, further reducing braking effectiveness.
• Deceleration rates dropped from 0.29g to 0.16g when the aircraft transitioned to the degraded concrete section of the runway.
5. Use of Reverse Thrust
• Propeller reverse thrust, a feature of the Q400, was not used during the landing roll. While rarely used in normal operations, earlier deployment of reverse thrust could have enhanced deceleration.
Safety Lessons and Risks
Findings as to Causes and Contributing Factors
1. The flight crew did not recognize their proximity to the runway end due to limited visual cues and focus on non-critical tasks.
2. Delayed braking and spoiler deployment reduced the available stopping distance.
3. Degraded runway surface texture and air contamination in the hydraulic system impaired braking performance.
Findings as to Risks
1. Insufficient training on the use of reverse thrust in critical scenarios increases the risk of runway overruns.
2. Lack of runway distance signage or edge lighting in older airports reduces situational awareness during night landings.
Conclusions
The runway overrun of Porter Airlines Flight PD-2691 was caused by a combination of delayed braking actions, technical factors, and degraded runway conditions. The crew’s situational awareness was compromised by an inaccurate mental model of their position, exacerbated by limited visual cues.
While the incident resulted in no injuries or significant damage, it highlights the importance of procedural adherence, robust braking systems, and enhanced runway markings to prevent similar occurrences.
Recommendations
1. Enhanced Runway Markings and Signage:
• Airports should install runway distance-remaining signs and adopt yellow edge lighting for the final third of the runway.
2. Training on Reverse Thrust Usage:
• Airlines should provide specific training on the effective use of reverse thrust during critical scenarios.
3. Improved Maintenance Protocols:
• Regular hydraulic system inspections should include checks for air contamination to ensure optimal braking performance.
4. Simulator Training for Night Landings:
• Emphasize situational awareness and decision-making under low-visibility conditions in simulator-based training.
5. Runway Surface Management:
• Airports should conduct regular texture surveys and resurfacing of degraded runway sections to maintain optimal braking conditions.
Safety Impact
This incident underscores the critical role of situational awareness, effective braking strategies, and robust runway infrastructure in ensuring safe landings. The findings are expected to influence both airport operations and flight crew training standards, contributing to improved safety for similar aircraft and operations.
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