On April 24, 2007, about 0720 Pacific daylight time, a Boeing 757-24APF, N402UP, operated by United Parcel Service (UPS) as flight 8007, rolled over a mechanic's foot during pushback from the ramp at Bob Hope Airport, Burbank, California. The two flight crewmembers were uninjured; the mechanic sustained serious injury. The airplane was not damaged. Visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 121 domestic cargo flight that was operating on an instrument flight rules (IFR) flight plan. The flight was originating from Burbank with a planned destination of Philadelphia International Airport, Philadelphia, Pennsylvania. In a written statement, a UPS representative reported that the injured mechanic was in communication with the tow tractor driver via headset. The mechanic was positioned to the right of the nose landing gear when he received a clearance from the flight crew to commence pushback. The tow tractor driver started the operation by turning the nose wheel left in an effort to align the airplane into position. The mechanic noticed a small airplane taxing behind the tail of flight 8007 and in response, gave a signal for the towing operations to stop. The tow tractor driver slowly applied the brakes and both men had their eyes affixed on the taxiing airplane. The airplane's wheel rolled over the mechanic's foot, which the tow tractor driver did not observe due to the position of the airplane's landing gear. After realizing the wheel was crushing the mechanic's foot he reversed the tow tractor. The representative further stated that the mechanic did not make visual contact with the driver when signaling to stop the tow, as his attention was placed on the taxiing airplane. Additionally the mechanic assumed the tow tractor had stopped and did not observe his position in reference to the nose landing gear. According to the injured mechanic, the tow tractor driver began pushing the airplane back from the ramp area to the taxiway. He was overseeing the pushback and noticed another airplane taxiing. Utilizing hand signals, he advised the tow tractor driver to stop. With the mechanic facing toward the tow tractor driver he took a few steps toward him, while keeping his eyes affixed to the other airplane. The incident airplane began to slow down and he noticed the nose moving toward him. He turned and the right wheel of the nose landing gear continued to roll over his right foot. The mechanic sustained numerous fractures in his foot and ankle. In a written statement, an Ameriflight supervisor reported that he was positioned in the passenger seat of the tow tractor (about 6 feet from the injured mechanic) during the incident. He estimated that about 35 to 40 seconds after the mechanic gave the appropriate signal to begin pushback, he then gave a signal for the pushback to stop. That signal was executed as a result of another airplane taxiing behind the incident airplane. The driver brought the tow tractor to a stop about 2 to 3 seconds after the command was given. The supervisor further stated that his attention was diverted to the other airplane, watching it pass by. He felt the tow tractor begin to move again at a slow pace and he did not perceive it to accelerate beyond that pace (the engine did not audibly increase in rpm). The mechanic was facing away from the tow tractor and nose landing gear. Although the supervisor's view was obstructed by the nose landing gear, he observed the mechanic walk and then stumble momentarily before falling to the ground. The tow tractor driver submitted a statement recalling the incident. He reported that during the pushback the mechanic signaled for the tow tractor to stop, at which point the tow bar (with tow tractor inline) were approximately 25 to 30 degrees to the nose of the airplane to the left. The driver noticed a small airplane taxi behind the incident airplane toward the tail section. He stopped the tow tractor and heard the mechanic shout in pain. The right wheel of the nose landing gear had rolled on top of the mechanic's right ankle. The operator's Ground Operations manual states that "all ground personnel involved in moving aircraft are individually responsible for remaining continuously alert for any potential collisions and remaining in view of the aircraft tow tractor driver at all times."