What happened
On March 3, 2009, an Aero Boero AB-115, registration PP-FKZ, was conducting a flight instruction mission at the Novo Hamburgo Aerodrome (SSNH) in Rio Grande do Sul, Brazil. The flight involved an instructor and a student pilot performing training maneuvers, specifically focusing on landings with go-arounds and short-field techniques.
During the final landing of the session, the student performed a standard landing. As the aircraft was on the ground and under control, the instructor attempted to demonstrate a short-landing technique by applying the brakes to achieve a rapid stop. During this braking application, the aircraft lost control and capsized on the runway. Both occupants of the aircraft escaped the incident without injuries, though the aircraft sustained severe damage to the engine and propeller, along with minor damage to the wings, fuselage, and vertical stabilizer.
The investigation
CENIPA's investigation focused on the mechanics of the braking maneuver and the aircraft's stability. Investigators examined the runway markings, which indicated that the tail of the aircraft had lifted during the landing roll. The inspection of the braking system revealed that the brakes were functioning correctly and did not lock up, ruling out mechanical failure as a cause.
The investigation also considered the operational environment, noting that the aircraft was within its specified weight and center of gravity limits. Investigators noted that the maneuver itself—executing a short landing with all wheels on the ground—is considered risky and uncomfortable by experienced pilots of this specific model. Furthermore, the investigation highlighted that the tandem seating configuration in the AB-115 can limit the instructor's ability to manage certain flight controls and instruments effectively during critical phases of flight.
Findings
- The primary cause of the accident was the excessive application of brakes by the instructor, which likely caused the aircraft to pivot around its lateral axis and capsize.
- There may have been a lack of coordination between the crew, potentially involving simultaneous brake applications or a conflict in control handover between the student and the instructor during the critical landing phase.
- The aircraft's design characteristics, including the position of the brake pedals and the inherent lateral instability of the conventional landing gear, may have contributed to the difficulty in maintaining control during heavy braking.