What happened
On July 19, 2014, an Aero Boero AB-180, registration PP-GCL, was conducting glider towing operations at the Bebedouro Aerodrome (SDBB) in São Paulo, Brazil. The aircraft, operated by Aeroclube de Pirassununga, had completed three successful landings prior to the incident. During the fourth landing attempt, after the tailwheel made contact with the runway, the aircraft began to drift toward the right side of the runway.
In an attempt to maintain the centerline, the pilot applied rudder corrections; however, when the directional control proved ineffective and the aircraft approached the runway edge, the pilot applied the brakes to prevent a runway excursion. This sudden braking caused the aircraft to nose over, resulting in the propeller and spinner striking the ground. The aircraft sustained substantial damage, but the pilot remained uninjured.
The investigation
The investigation examined the environmental conditions, the aircraft's mechanical state, and the pilot's actions. At the time of the occurrence, the wind was recorded as a right crosswind of approximately 5 knots with occasional gusts. The investigation noted that the aircraft came to a stop 600 meters from the threshold of runway 31, leaving significant runway remaining.
Investigators reviewed the aerodynamic characteristics of conventional gear aircraft, noting that the increased surface area behind the main gear axis creates a natural tendency for the aircraft to weathercock into the wind. The investigation also confirmed that while the pilot held valid medical and technical certifications, they lacked the specific authorization required for glider towing operations.
Findings
- Improper use of braking during the landing roll.
- Pilot judgment regarding the management of the landing roll and runway centerline.
- Lack of specific authorization for the pilot to perform glider towing operations.
- Ineffective application of directional controls to counteract the crosswind drift.