What happened
On July 19, 2008, a Piper PA-38-112, registration CS-DDC, was performing a local training flight at the Lezíria aerodrome in Porto Alto, Vila Franca de Xira. After departing from runway 28, the pilot returned to land on runway 10. To minimize wear on the brakes and conserve fuel, the pilot opted for a landing with a tailwind component and allowed the aircraft to decelerate naturally without using the brakes.
Approximately 200 meters along the runway centerline, the aircraft began to drift to the right. The pilot attempted to correct the deviation using the rudder and differential braking on the left wheel, but was unsuccessful. The aircraft exited the paved surface, traveled through tall, dry vegetation on the shoulder, and eventually entered a drainage ditch. The aircraft came to a halt after the nose and propeller struck a perimeter fence, causing significant damage to the airframe.
The investigation
The GPIAAF investigation focused on the mechanical state of the braking system and the pilot's proficiency. Investigators examined the hydraulic lines and found that the left wheel brake line had fractured. Evidence suggested this was not a new failure; the fracture showed signs of being old, and the brake disc was covered in corrosion, indicating it had not been used recently. The system was found to be completely devoid of hydraulic fluid.
Furthermore, the investigation reviewed the pilot's flight history, noting a pattern of irregular flight activity. The pilot had experienced significant gaps in flying experience, including a period of over 13 months without flight prior to the accident, and had returned to solo flight without a recent proficiency check with an instructor.
Findings
- The primary cause of the accident was the loss of directional control of the aircraft following landing.
- A contributing factor was the inability to use the left wheel brake due to a lack of hydraulic fluid caused by a pre-existing fracture in the brake line.
- A crosswind component from the right (approximately 10 knots) contributed to the aircraft's tendency to veer off the runway.
- The pilot's limited and irregular flight experience may have prevented the detection of the mechanical anomaly during a pre-flight inspection.
- The aircraft sustained substantial damage, including fractures to the nose and left main landing gear, damage to the propeller, and structural deformation to the fuselage and wing.