What happened
On March 14, 2004, a Premier 390, registered N4395D, was performing an IFR flight from Caldas Novas to São Paulo/Congonhas (SBSP). The aircraft, operated temporarily by Líder Táxi Aéreo, was carrying two crew members and two passengers. At the time of landing, the airport was experiencing IMC conditions with moderate rain, a 700-foot ceiling, and 2,000-meter visibility.
Radar data indicated that the aircraft approached the runway at approximately 130 knots, which was 21 knots above the planned Vref of 109 knots. Upon touchdown on runway 35L, the crew attempted to decelerate on the wet surface. During the landing roll, the co-pilot retracted the flaps and applied the emergency brake. The application of the emergency brake deactivated the anti-skid system, causing the wheels to lock up and inducing a hydroplaning condition. To prevent the aircraft from overrunning the runway, the pilot applied left rudder, causing the aircraft to pivot approximately 170 degrees and slide off the runway onto taxiway "E".
The investigation
The CENIPA investigation focused on the sequence of aerodynamic and mechanical events during the landing roll. Investigators examined the aircraft's braking systems, including the anti-skid control box and wheel speed transducers, finding the hardware to be functioning within operational parameters. The investigation also analyzed the crew's decision-making process, specifically the decision to retract flaps and use emergency brakes on a wet runway. The investigation noted that the pilot in command had only 30 hours of experience in this specific aircraft type, while the co-pilot was more experienced in the type but lacked instructor qualifications.
Findings
- Adverse weather conditions, specifically moderate rain that rendered the runway slippery, contributed to the loss of traction.
- Inadequate approach speed, with the aircraft touching down 21 knots faster than the prescribed Vref.
- Improper use of aircraft systems, specifically the retraction of flaps and the activation of the emergency brake, which suppressed the anti-skid system and led to wheel lock-up.
- Deficient Crew Resource Management (CRM), characterized by a lack of coordination between the crew and a failure by the commander to correct the co-pilot's inappropriate actions.
- Lack of situational awareness, resulting in a failure to execute a go-around despite the high approach speed and deteriorating landing conditions.