What happened
On 29 November 2002, a Cessna 152, registration G-BSTO, was conducting a private night flight from Plymouth Airport, Devon. The pilot, who was performing a solo night circuit to renew currency, was accompanied by a passenger. During the approach to Runway 31, the pilot utilized the Precision Approach Path Indicator (PAPI) for guidance. However, during the final stages of the approach, the pilot shifted the flight path to aim for the runway end lights rather than the displaced threshold.
Upon touchdown, the aircraft landed in the grass undershoot area, approximately 14 metres short of the turning circle. The aircraft traversed the grass before returning to the paved runway surface, where it was able to taxi back to the parking area. There were no fatalities and no injuries to the occupants, though the aircraft sustained minor damage to the left wheel brake assembly.
The investigation
Investigators examined the runway configuration at Plymouth, noting that the threshold for Runway 31 is displaced, leaving a landing distance of 1,045 metres. The investigation also reviewed the lighting setup, which includes a coded centerline and specific markers for the displaced threshold and turning circles.
Physical inspections of the airfield revealed damage to one centerline approach light and one runway end light, which matched damage found on the aircraft's left tyre and brake assembly. While the pilot considered the possibility of windshear causing a loss of airspeed, the soft nature of the touchdown made this unlikely. The investigation focused on the pilot's visual reference during the approach.
Findings
- The pilot intentionally altered the approach path to aim for the runway end lights instead of the threshold.
- The pilot may have misidentified the runway end lights as the threshold lights during a brief period of instrument monitoring.
- The aircraft touched down in the Runway End Safety Area (RESA) in the grass undershoot.
- The pilot's habit of aiming for the threshold during daylight operations influenced the decision-making during the night approach.