EasyJet flight 1985, a scheduled service from Manchester, U.K. to Copenhagen, Denmark, was cancelled after a tow truck jack-knifed and became stuck under the aircraft’s fuselage. During the pushback from Stand 1 at Manchester Airport, in dark and wet conditions, the flight deck crew felt a fore and aft jolt and heard a mechanical “clunk”. The commander informed the headset operator who conferred with the tug driver, and then visually checked the towbar and its attachment to the tug and to the aircraft. The ground crew saw nothing abnormal and they assumed the clunk was due to the tow hitch shifting, which is a familiar occurrence. The headset operator informed the commander that all was well, and the pushback continued. In response to a request from the commander, the headset operator indicated the left engine could be started, although the aircraft had not reached the designated engine start positon for that stand. As the aircraft was halted, in preparation for being pulled forward to the release point, the headset operator approved a request from the flight deck crew to start the right engine. The commander was conscious of the aircraft beginning to move gently forward, while he was concentrating on starting the right engine. Both the tug and the headset operator were concealed from his field of view and he was not surprised when the aircraft’s nose turned first to the right and then to the left, as if it was being lined-up on the taxiway centreline. He then heard an urgent instruction from the headset operator for the brakes to be applied, so he responded by pressing on the toe brakes before setting the park brake. The headset operator then informed him that the tug and aircraft had collided, but that nobody was injured. Both engines were then shut down. Ground crew from adjacent stands came to assist and found the towbar was still connected to both the tug and to the aircraft. The nose gear leg was rotated approximately 90ø to the left and the tow bar was bent around the front corner of the tug. The shear pins on the towbar had fractured, and pieces were later found within the boundary of the stand, but the central retaining pin remained intact. The passengers and crew disembarked without injury from the rear right exit door. An investigation by the ground handling company showed One of the pins on this towbar had failed 16 days before the accident and only that pin had been replaced. It was also established that other maintenance procedures for the shear pins had not been followed. They had not been lubricated correctly and the training given to ground crews did not prepare them for conducting adequate serviceability checks on the pins. No Probable Cause was issued by the AAIB