What happened
On May 26, 2005, an Alitalia McDonnell Douglas MD 80, registration I-DAWD, was undergoing a pushback operation at Prague Ruzyně Airport (LKPR). After completing standard pre-flight procedures and receiving clearance from ATC, the aircraft was being pushed from stand A5 to taxiway B1. During the process, the flight crew started both engines.
Once the aircraft reached taxiway B1, the pushback was temporarily halted. The ramp controller then received instructions from the pilot in command (PIC) to move the aircraft from taxiway B1 to taxiway B2. The tug driver re-engaged the aircraft to begin the second movement. As the aircraft was being maneuvered into a left-hand turn to align with taxiway B2, the tug performed a sharp right-hand turn to follow the path. This maneuver caused the tug to drift toward the right side of the aircraft. The aircraft's momentum caused it to overtake the tug, and the driver likely reacted by braking.
As the tug slowed, the aircraft's mass and inertia pulled the tug underneath the airframe. The tug's cabin structure struck the right side of the fuselage, causing a puncture in the aircraft skin measuring approximately 150 x 70 cm and damaging the air conditioning ductwork. The impact also caused the nose gear to be wrenched from its position. During the collision, the ramp controller, who was standing on the tug's step, fell to the ground, resulting in a loss of radio communication with the cockpit.
There were no injuries among the 5 crew members or 125 passengers on board.
The investigation
The ÚZPLN investigation examined the sequence of events, the movement of the tug, and data from the aircraft's Quick Access Recorder (QAR). The investigation established that the pilot, ramp controller, and tug driver were all properly qualified and that all personnel had tested negative for alcohol. The aircraft and the Douglas Kalmar TLB-180 tug were both in serviceable condition, and the taxiway surfaces were dry and clean. The investigation also noted that the ramp controller was standing on the tug's step, which was in violation of ground handling procedures.
Findings
- The primary cause of the incident was the tug driver's instinctive braking in response to the sharp right-hand maneuver required to align with taxiway B2.
- The deceleration of the tug, combined with the momentum of the McDonnell Douglas MD 80, caused the tug to be pulled under the aircraft.
- The collision resulted in structural damage to the aircraft fuselage and the tug's frame, steering mechanism, and nose gear coupling.