What happened
On November 20, 2011, an Aero Boero AB-115, registration PP-GLA, was conducting a commercial pilot training flight from Paranaguá to Itanhaém, Brazil. During the flight, the crew noticed a fuel imbalance: the left tank was depleting while the right tank showed no consumption. The crew attempted various maneuvers and fuel selector adjustments to restore flow, but the imbalance persisted.
Unable to resolve the issue, the crew opted for a precautionary landing at Balneary São Januário (SDBV), an abandoned grass field. The initial landing was successful and the aircraft sustained no damage. After the landing, the crew performed an engine run-up, during which they observed the fuel levels equalizing. Following this, the crew decided to reposition the aircraft and attempt a takeoff from the same field.
During the takeoff roll, the right landing gear sank into the soft, uneven terrain, causing the aircraft to nose over (pilonagem). The aircraft sustained substantial damage, though both occupants escaped without injury.
The investigation
The investigation examined the fuel system and the conditions of the landing site. Post-accident inspections of the PP-GLA revealed that the fuel lines, junctions, and engine were all in normal working order. Investigators could not definitively determine the cause of the initial fuel imbalance, though they considered possibilities such as an air bubble in the fuel line, a temporary blockage, or a momentary issue with the fuel selector.
The investigation also evaluated the takeoff attempt. It was determined that the runway surface was in poor condition, featuring depressions, vegetation, and wet patches. The available takeoff distance was approximately 200 meters, which was considered marginal for the circumstances.
Findings
- The crew attempted to take off from an unprepared, abandoned field without conducting a thorough inspection of the surface conditions.
- The decision to attempt a takeoff was made without consulting takeoff distance tables for the specific terrain conditions.
- Inadequate pilot judgment and decision-making regarding the risks of operating from an unmaintained strip contributed to the loss of control.