B737 Next Generation Undifferentiated
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 561
Ground Event / Encounter Other / Unknown
Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification
Airport
During taxi out on BOS Taxiway K in a heavy aircraft; Ramp Control advised us to hold at Spot 7. We held just prior to the Spot 7 pavement marking. When cleared to taxi to the runway; I released the parking brake and advanced the thrust levers to approximately 35 percent; and the aircraft would not move. We were in the alleyway; and I was very aware that I did not want to use excessive thrust to avoid damage to aircraft; equipment; and Personnel behind us. We called Ramp Control to clear all aircraft and Personnel from behind us so we could use a higher thrust setting. Ramp Control cleared the path behind us; and we advised them that we needed to use a higher thrust setting in an attempt to move forward. I released the parking brake and advanced the thrust levers to 35; 40; 45; 50; 55; and finally 60 percent. The aircraft did not move. I called Maintenance Control to determine if B737 brakes have a history of 'locking' up.The Maintenance Representative said the brakes have no history of locking up. Ramp Control then told us that last week an aircraft was stuck in the exact same place. We considered that our main tires might be stuck in a rut in the blacktop. We called Company BOS Operations to have a tug assist us. We shut off the A hydraulic pumps and released the parking brake. The tug could not budge us at all while pushing us. The Ramp Agents determined that our main tire(s) were in a big (4 inch) depression in the blacktop where aircraft always stop in the same place. We started the APU; shut down both engines; and the tug began to rock us back and forth. Finally; the tug was able to push us back out of the rut. The Tug Driver confirmed that all our main tires were rolling and not skidding. We released the Tug Driver and Ramp Agents. We started the engines; taxied around the rut to the runway with no further problems. As we taxied past the rut just prior to the Spot 7 yellow triangle marking; we noticed barely noticeable paint markings indicating that someone may have previously marked the edges of the rut for repair. However; as of this date; the repair had not been done. BOS Airport Facilities Maintenance Team needs to repair the rut(s) in the blacktop pavement on Taxiway K near Spot 7. Until it is repaired; Pilots need to be made aware of this potential hazard via ATIS; NOTAMS; etc.
B737NG Captain reported the aircraft got stuck in a rut near spot 7 at BOS which required a tug to push the aircraft free.