What happened
On November 18, 2009, an Aero Boero AB-115, registration PP-GGG, was performing a flight instruction mission at the Piracicaba Aerodrome (SDPW) in São Paulo. After completing initial startup procedures, the crew taxied toward runway 35. Upon reaching the runway threshold, the instructor observed deteriorating weather conditions, including dark cloud formations and increasing wind speeds indicated by the windsock.
Deciding to cancel the flight, the instructor directed the student pilot to return to the parking apron via the main runway. During this return taxi, the aircraft was struck by a powerful left crosswind gust. The force of the wind lifted the left wing, and despite the crew's attempts to maintain control using the brakes and flight controls, the aircraft drifted off the runway and rotated 180 degrees. The impact caused the right landing gear strut to break, subsequently forcing the right wing into the ground.
Both the instructor and the student pilot were uninjured.
The investigation
CENIPA's investigation focused on the environmental and operational factors present during the taxi excursion. Investigators noted that the aerodrome lacked an anemometer and a dedicated meteorological information service, making it difficult to confirm the exact wind velocity at the moment of impact. However, pilot reports and witnesses confirmed a significant gust.
The investigation also identified geographical and infrastructural elements that exacerbated the event. A group of trees near the runway threshold creates a localized area of channeled, stronger airflow. Additionally, investigators discovered an uncovered ditch between the taxiway and the runway, which contributed to the severity of the excursion.
Findings
- The primary cause of the excursion was a strong surface wind gust that overcame the crew's control inputs.
- The instructor's decision-making regarding the timing of the flight was a contributing factor, as the presence of heavy cloud formations was visually apparent.
- The presence of an uncovered ditch between the runway and taxiway increased the risk of damage during the excursion.
- The aircraft sustained severe damage to the right wing and right landing gear, along with minor damage to the right elevator.
Safety action
CENIPA issued the following recommendations to the São Paulo State Aerodrome Department (DAESP):
- Cover the ditch located between the runway and the taxiway to improve operational safety.
- Install a Meteorological Information Service at the Piracicaba Aerodrome to provide the aviation community with necessary weather data for safe operations.