What happened
On May 5, 2008, at São Luís Aerodrome (SBSL), an Airbus A320-214, registration PR-MHK, was undergoing a pushback procedure on the apron. The operation was being coordinated via interphone between the flight crew and a maintenance mechanic monitoring the procedure from the ground. During the engine start-up sequence, the aircraft was being pushed back by a tug.
As the pushback reached its conclusion, the mechanic began removing the tow-bar. However, he failed to notify the flight crew to apply the parking brake. Due to the aircraft's operating engines and the natural declivity of the pavement, the aircraft began to move forward. During this movement, the nose landing gear struck the mechanic, trapping his left leg under the nose gear tire. The flight crew immediately reacted by activating the brakes and shutting down the engines to stop the movement. The mechanic sustained serious injuries to his left leg.
The investigation
CENIPA's investigation established that the mechanic was an experienced professional who had completed all required training and was familiar with the airline's standardized work instructions for pushback and communication. The investigation found that the aircraft's braking and communication systems were fully functional and that the flight crew had sufficient experience for the operation.
Investigators noted that the apron at SBSL suffered from deficient lighting, which could have hindered ground operations. Additionally, the response time of the medical service was noted as excessive, taking approximately six minutes to reach the aircraft on the apron.
Findings
- The mechanic failed to comply with standardized procedures, specifically failing to request that the crew apply the parking brake upon completion of the tow.
- The mechanic's failure to follow prescribed safety instructions was the primary contributor to the accident.
- A lack of attention or a potential lapse in memory during the routine task led to the deviation from safety protocols.
- Inadequate lighting on the airport apron may have contributed to the degradation of ground service performance.
- The terrain's declivity allowed the aircraft to move forward once the tow-bar was released and the brakes were not set.