What happened
On 29 September 2021, a Britten Norman 2B-26 Islander, registration J8-VBI, was performing a commercial passenger flight at John A. Osborne Airport, Montserrat. The aircraft, carrying one pilot and six passengers, was completing a scheduled return leg from Antigua.
During the landing roll on Runway 10, the pilot applied the brakes immediately after the main gear touched down, but before the nosewheel had made contact with the pavement. The pilot noted that the left brake felt "spongy" and lacked effectiveness. This imbalance caused the aircraft to lose directional control, veering to the right side of the runway. The aircraft departed the paved surface approximately 242 metres from the threshold and eventually came to rest in a drainage ditch. While there were no fatalities, the aircraft sustained damage beyond economic repair. One passenger was a minor, and all occupants escaped without injury.
The investigation
Investigators examined the aircraft's braking system and identified a slight brake fluid leak originating from one of the pistons in the left outboard brake calliper. This leak prevented the achievement of full brake pressure on the left side, creating an asymmetric braking effect. Detailed component analysis revealed scoring in the piston bore and a flattened O-ring seal.
The investigation also reviewed the pilot's technique and the operator's procedures. It was noted that the pilot applied the brakes while the nosewheel was still airborne, a technique that prevents the use of nosewheel steering to correct directional deviations. Furthermore, the investigation looked into the operator's manuals and regulatory compliance regarding airport-specific instructions for Montserrat.
Findings
- A leak in the left outboard brake calliper caused asymmetric braking.
- The pilot's use of braking before the nosewheel touched the ground prevented the use of nosewheel steering to maintain the aircraft's path.
- The operator's manual lacked necessary performance data for wet runway operations.
- There was a lack of published emergency procedures for handling a loss of braking.
- The operator had not fully complied with specific training and documentation requirements for operating at the Montserrat airport.