Introduction
An incident occurred during a pushback sequence where the aircraft began to taxi before the tug had moved clear. The event involved the flight crew, ground crew, and an Aircraft Maintenance Engineer (AME). The source indicates that multiple misunderstandings among the parties led to incorrect expectations about when taxi would commence.
Sequence of Events
At the conclusion of the pushback, the AME displayed the bypass pin to the flight crew. The flight crew interpreted this as confirmation that all vehicles and equipment were clear and that it was safe to start taxi. The ground crew, however, anticipated that taxi would start only after all personnel and equipment had crossed a line marking the boundary of the S7 disconnect point.
Expectations and Communications
Both the flight crew and the AME believed that the aircraft would not receive a taxi clearance from ATC until ATC confirmed that the tug and AME were clear. The misunderstandings among the parties during this sequence likely resulted in incorrect expectations about the timing of taxi initiation. The aircraft began to taxi before the tug had moved clear.
Procedural Requirements
The flight crew's procedures required them to visually verify that all ground equipment was clear of the aircraft before taxi. The first officer determined that the tug and tow bar were clear of the right engine, but they were not. The source suggests that this perception may have been influenced by the expectation that they were clear, given the communications with the AME and the taxi clearance from ATC.