What happened
On September 4, 2022, a Boeing 777F freighter was taxiing on the N-North taxiway at Frankfurt Main Airport, preparing for a scheduled cargo flight to New York Kennedy. While maneuvering, the aircraft's pilot attempted to navigate a 90-degree left turn into taxiway N17. Because the aircraft had previously stopped mid-turn to avoid encroaching on a restricted area, the pilot applied thrust to resume movement.
During this process, the pilot increased the thrust of the right engine from idle to 47% N1, while the left engine remained at idle. The resulting jet blast was directed toward parking position F234, where another aircraft was being loaded. The high-velocity exhaust caught several empty cargo containers on nearby dollies, blowing them across the apron. One container struck a ground worker, causing her to fall and sustain a fracture to her left upper arm bone. Other containers were scattered near the aircraft and the area where the worker was standing.
The investigation
The BFU investigation examined Quick Access Recorder (QAR) data, which confirmed that the right engine thrust was increased significantly while the left engine remained at idle. The investigation also reviewed the aircraft's Flight Crew Training Manual (FCTM) and Flight Crew Operating Manual (FCOM), as well as the airport's Aeronautical Information Publication (AIP). Witnesses, including the ground crew and the pilot, provided statements regarding the sequence of events and the engine power settings used during the maneuver.
Findings
- The pilot applied asymmetric thrust by increasing power only on the right engine to initiate movement after a mid-turn stop.
- The pilot did not monitor the engine power indicators during the thrust application.
- The high-velocity exhaust from the right engine was directed toward the active loading area at position F234.
- The airport AIP regulations required aircraft to use only the minimum thrust necessary for taxiing and prohibited significant power increases above idle for heavy aircraft near buildings or other stands.
- The airline's manuals required pilots to be aware of equipment and structures behind the aircraft when engines are above idle thrust, but did not explicitly mandate synchronous thrust for all taxiing scenarios.