What happened
On 15 February 2019, a Boeing 777-258, registration 4X-ECC, operated by El Al Israel Airlines, was undergoing pushback and towing operations at Warsaw Chopin Airport (EPWA). The flight was designated as a HEAD status flight (VIP).
During the pushback phase, the flight crew began the start-up of the right engine. As the operation transitioned into the towing phase, the crew commenced the start-up of the left engine. During a right-hand turn, the left shear pin of the towbar failed. Although the shearing of the pin was noticed by ground personnel, the towing operation was not aborted.
As both engines reached idle RPM, the aircraft gained enough independent thrust to accelerate to 3 kt. Because the towbar connection had lost its structural stiffness due to the failed pin, the aircraft began to overtake the tractor. This resulted in a collision between the aircraft's nose and the raised cabin of the towing tractor, causing damage to the lower fuselage skin.
The investigation
The PKBWL investigation examined the sequence of events, the mechanical integrity of the towbar, and the operational procedures of the ground handling staff. The investigation reviewed CCTV footage, flight data recorder (FDR) parameters, and the configuration of the towbar shear pins. The commission also assessed the impact of environmental and operational pressures on the ground crew.
Findings
- The direct cause of the incident was the failure of ground personnel to react to the shearing of the towbar pin, leading to the continuation of the towing operation.
- The towbar shear pins were incorrectly configured; they were set for an aircraft with a lower mass than the Boeing 777-258 being towed.
- The simultaneous start-up of both engines during the pushback-towing process allowed the aircraft to move independently of the tractor.
- Ground handling staff were subject to significant contributing factors, including fatigue from extended night shifts in adverse weather, as well as high stress levels associated with servicing a VIP flight.
- The investigation noted that CVR recordings were overwritten due to a failure to disconnect power after the incident, which prevented a full assessment of the communication between the crew and the ground coordinator.