What happened
On November 21, 2015, at approximately 19:30 UTC, an Aero Boero AB-180, registration PP-GSE, was performing glider towing operations at the Garibaldi Aerodrome (SSGA) in Rio Grande do Sul, Brazil. The aircraft departed from runway 32 to perform a local towing mission. Following the completion of the flight, the pilot released the tow cable at the threshold of runway 32 and proceeded to land further down the runway.
During the landing roll, the aircraft began to drift to the right. The pilot attempted a go-around to recover the aircraft to the runway centerline; however, the maneuver was ineffective due to insufficient airspeed and distance. The aircraft subsequently exited the runway to the right, descended an embankment, and collided with several trees. The aircraft sustained substantial damage, but the pilot remained uninjured.
The investigation
CENIPA's investigation focused on the operational procedures and environmental factors at the time of the accident. Investigators examined the runway topography, noting that the runway features a 1% upgrade for the first 500 meters and a 3.8% downgrade for the following 700 meters. The investigation established that the pilot had been intentionally landing on the downhill section to facilitate the quick release of the tow cable and avoid additional traffic patterns, thereby saving fuel.
Furthermore, the investigation analyzed the wind conditions, which were recorded at approximately 185° at 06 knots. This resulted in a tailwind component for the landing performed in the 32-14 direction. The investigation also evaluated the airport infrastructure, specifically the proximity of an embankment and trees to the runway edge, and reviewed the management oversight of the glider towing operations at the Aero Clube de Bento Gonçalves.
Findings
- The pilot's flight planning was inadequate, as it prioritized fuel economy over safety by choosing to land with a tailwind and on a downhill slope.
- There was a failure in pilot judgment and perception, specifically regarding the decision to attempt a go-around when the aircraft lacked the necessary speed and runway distance.
- The application of flight controls was ineffective in maintaining the aircraft within the runway limits.
- The airport infrastructure contributed to the severity of the impact, as the nearby embankment and trees maximized the damage to the aircraft.
- There was a lack of effective management supervision regarding the standardization of glider towing procedures.