Incident Overview
On an executive flight from Curitiba-Afonso Pena Airport to Foz do Iguaçu-Cataratas Airport, the aircraft departed at 1240 local time with one passenger and two pilots. After an uneventful flight, the crew initiated a descent to Foz do Iguaçu. The airplane landed on wet runway 32 following a stabilized approach. Upon touchdown, the crew experienced difficulties bringing the aircraft to a stop. The airplane overran the runway and came to rest in a ravine, sustaining substantial damage. All three occupants evacuated safely.
Landing and Overrun
The flight crew reported that the approach was stable. The required landing distance was 1,960 meters, while the available landing distance of runway 32 was 2,195 meters, indicating compatibility. No malfunctions were found in the brake system. The runway surface was wet with a significant amount of water. The estimated deceleration matched that expected on a very wet runway with more than 3 mm of water, consistent with hydroplaning at higher speeds. Friction and macrotexture measurements were normal and did not explain the poor deceleration.
Investigation Findings
The official investigation identified several key findings. The precipitation over threshold 14, combined with large wind direction and intensity variations, was consistent with a microburst and resulting windshear. The aircraft's sensors did not detect windshear during the approach. However, a sudden increase in calibrated speed of up to 32 knots altered lift and reduced tire grip, leading to poor braking when ground speed was lower. The speedbrakes were not deployed after landing, contrary to the aircraft flight manual procedures. The airplane traveled the full runway length, overran, and entered a ravine. A windshear alert was issued by another aircraft about 30 seconds after landing.
Contributing Factors
Contributing factors identified include the non-extension of speedbrakes, which, despite their limited effect on landing distance, provide aerodynamic drag that should not be neglected, especially on wet runways. Adverse meteorological conditions, specifically a wind variation of 32 knots lasting 13 seconds, raised the indicated airspeed from 76 to 108 knots, close to the reference speed. This phenomenon increased lift and reduced tire grip, resulting in inadequate braking.