Incident Description
During a pushback from the gate, the tug driver was positioning the nose wheel on a painted stop mark known as the 'T' when the tail of the aircraft struck a pedestrian walkway between concourses. The walkway had been constructed previously, reducing the ramp space available during pushback to substantially less than the length of the airplanes operated by the airline. The 'T' had not been repositioned to account for the reduced clearance.
Sequence of Events
On the morning of the accident, the ramp coordinator advised the ramp 1 supervisor that pushbacks to the 'T' at this gate would resume that morning. The ramp 1 supervisor asked for confirmation due to concerns over adequate clearance, and the instruction was reconfirmed that all gates on ramp 1 would push to the 'T.' No coordination was made with the ground operations safety supervisor. Ramp control cleared the flight to push to the 'T,' and the captain relayed the clearance to the tug driver. Wing walkers were properly positioned. When the aircraft was about 20 feet from the walkway, the right wing walker saw the impending collision and signaled the tug driver to stop. The tug driver stated he was focused on correctly positioning the nose wheel on the 'T' and did not see the signal in time to stop the aircraft. About 10 feet before reaching the 'T,' the aircraft's right horizontal stabilizer struck the pedestrian walkway.
Communication and Procedures
There is no voice communication capability between the crew chief at the gate, the tug driver, and the wing walkers. Company procedures required each tug driver to put the nose wheel on the 'T' during pushback. This procedure had been previously discontinued at this gate due to the construction of the pedestrian walkway that did not allow sufficient clearance. The original decision to resume the pushback originated with the ACS project manager but should have been coordinated with the ground operations safety supervisor prior to any operational changes being implemented.