What happened
Following pushback from a new terminal, the flight crew reviewed NOTAMs which included a warning regarding an unmarked and difficult-to-see ditch located directly across from the terminal. Although the crew had discussed this ditch during preflight and upon their earlier arrival at the airport, they did not visually identify the hazard.
While taxiing across the ramp to a hold point, the crew requested a change in runway due to weight considerations. Ground control issued a new clearance directing the aircraft to turn right on the outboard parallel taxiway. During this process, the captain confused his position on the taxiway diagram, mistaking Spot 4 for taxiway C4.
As a result of this navigational error, the captain taxied the aircraft across taxiway C and through the ditch before completing a right turn onto taxiway Bravo. Following the encounter with the ditch, the flight crew determined there were no unusual symptoms with the aircraft and proceeded to their destination without further incident. The flight attendants did not report any significant motion in the rear of the cabin, and the crew did not inquire about the ride quality.
The minor damage to the aircraft was discovered later by an oncoming crew.
Findings
At the time of the event, the infield area lacked lighting or markings to illuminate the ditch, and there were no boundary hazard markings present. This incident followed a similar occurrence involving another air carrier one month prior. In response to these two incidents, airport operations installed plastic reflective delineators around the area to mark the hazard.