What aircraft was involved and where did it happen?

The accident on 2012-01-24 involved a Cessna 152, registration G-CGSP, at Leiria, PT.

What was the probable cause of the accident?

The aircraft veered off the runway due to the application of heavy braking during a high-speed landing, which caused asymmetric braking forces and a loss of directional control.

Cessna 152 Excursion from Runway at Leiria Aerodrome

A Cessna 152 veered off the runway and into the grass during landing at Aeródromo José Ferrinho, resulting in minor damage to the propeller and landing gear.

What happened

On January 24, 2012, at approximately 16:30 UTC, a Cessna 152, registration G-CGSP, was performing a local flight at Aeródromo José Ferrinho in Leiria, Portugal. The aircraft, operated by a private owner in service for the Aero Clube de Leiria, was carrying a pilot and one passenger.

During the landing phase on runway 02, the aircraft touched down near the middle of the runway. The pilot attempted to decelerate the aircraft, but as braking pressure was applied, the aircraft began to deviate toward the right side of the runway. The aircraft eventually exited the paved surface, traveling approximately 30 meters onto the grass before coming to a halt near a public road crossing the runway. The occupants exited the aircraft uninjured.

The investigation

The GPIAAF investigation examined the flight history, the aircraft's mechanical condition, and the environmental factors at the time of the incident. Investigators noted that the weather conditions were favorable, with clear skies and calm winds, ruling out meteorological factors as contributors.

Technical inspections of the aircraft's braking system by a qualified mechanic found the right main brake to be functioning correctly and the brake pads to be in good condition. However, investigators considered the possibility of air trapped in the left brake hydraulic line, noting a similar recent incident involving another aircraft maintained by the same company where air in the system had caused reduced braking effectiveness.

Physical evidence at the scene showed that the nose wheel dug into a deep furrow in the uncompacted soil at the runway edge. This sudden deceleration and the resulting nose-down movement reduced the propeller clearance, causing the propeller blades to strike the ground and sustain damage. The investigation also identified damage to the landing gear, flaps, and the left wing underside.

Findings

The pilot performed a landing approach that was slightly higher and faster than recommended, resulting in a touchdown point near the middle of the runway.
In an attempt to stop the aircraft before the runway crossing, the pilot applied maximum braking, which inadvertently caused a predominance of braking on the right side.
This asymmetric braking led to a loss of directional control, causing the aircraft to veer off the right side of the runway.
The uncompacted nature of the terrain at the runway edge allowed the nose wheel to dig into the ground, leading to the fracture of the left nose wheel steering control cable and propeller contact with the soil.