What happened
On 23 September 2019, a Britten-Norman Islander, registration VP-MNI, was conducting a commercial passenger flight from Antigua to Montserrat. Following heavy rain showers, the pilot approached Runway 10, which was wet from recent precipitation. Although the pilot intended to land at a standard approach speed of 65 KIAS, CCTV footage later revealed a touchdown groundspeed of 79 kt.
Upon landing, the pilot applied the brakes, but the aircraft failed to decelerate effectively. The aircraft skidded along the runway, eventually veering off the paved surface approximately 19 metres before the runway end. The pilot attempted to steer the aircraft to the right to avoid the edge of the airfield, causing the plane to rotate 1ered 180 degrees. The aircraft then slid down a steep, 45-degree incline at the end of the runway, eventually coming to a halt when the tail section struck the airport's perimeter security fence. There were no fatalities and no injuries among the six passengers or the pilot.
The investigation
The AAIB examined the aircraft's mechanical condition, the runway surface, and the aerodrome's emergency response capabilities. Investigators found no mechanical defects in the braking system, tyres, or engines that contributed to the event. Analysis of the runway surface showed that friction levels were non-uniform, with some areas potentially falling below maintenance planning levels.
CCTV analysis was critical in determining that the touchdown speed was significantly higher than the required threshold for the available landing distance. The investigation also looked into the topography of the airfield, noting that the steep terrain at the end of Runway 10 presents a significant hazard during an overrun.
Findings
- The primary cause of the accident was the excessive touchdown groundspeed of 79 kt, which was significantly higher than the normal approach speed.
- The high speed, combined with a wet runway surface, increased the required landing distance beyond what was available.
- The aircraft experienced skidding rather than aquaplaning, as evidenced by tyre marks that indicated the tyres were in contact with the pavement.
- The steep embankment at the end of the runway increased the risk of significant damage and difficulty for rescue services.
Safety action
Following the investigation, the AAIB issued several safety recommendations:
- Operators and pilots should account for local wind variations when using John A Osborne Airport.
- The airport operator should ensure adequate access to the 'Difficult Environs' at the east end of Runway 10 to allow emergency services to reach accident sites quickly.
- The airport operator should install a mechanism to arrest the progress of aircraft that overrun either end of the runway.