On June 6, 1996, at 2205 hours Pacific daylight time, a United Airlines Boeing 737-322, N371UA, operating as scheduled passenger flight number 2546 to Seattle, Washington, collided on the ground with an American Airlines Boeing 767-223, N335AA, operating as scheduled passenger flight number 18 to New York City, New York. The collision occurred between the "E" and "F" concourses in an alleyway at the San Francisco International Airport, San Francisco, California. At the time, the United aircraft was under tug control while being pushed back from gate number 77, and the American aircraft was commencing to taxi for takeoff from the same alleyway following its uneventful pushback from gate number 63. During the aircraft tail-to-tail collision, the United aircraft was substantially damaged, and neither its 5 crew members nor 50 passengers were injured. The American aircraft received minor damage, and neither its 11 crew members nor 154 passengers were injured. Use your browsers 'back' function to return to synopsisReturn to Query Page
The captains in both aircraft had received clearances for their respective pushbacks, and the American aircraft was pushed back first. According to American, wing walkers had been used during the pushback operation, and its aircraft was positioned at its customary location in the alleyway. Thereafter, the captain started both engines. The push tractor disconnected from the aircraft, and along with the wing walkers proceeded back to the gate. Upon arrival at the gate one of the wing walkers observed that the aircraft had just been impacted by a United aircraft.
According to a representative from United Airlines, no wing walkers were used during its pushback operation. Also, it was United's policy that prior to pushing the accident aircraft into the alleyway, it was the tug driver's responsibility to ensure that adequate clearance existed from other aircraft.
The United tug driver reported, in pertinent part, that after initiating the pushback she slowed her speed to allow for the passage of a food service truck. Then she continued with the pushback operation and looked for the lead-in line where the aircraft was to be positioned in the alleyway. The tug driver further reported that approaching the lead-in line the aircraft "lunged toward me abruptly." The tug driver asked the pilot what was wrong and whether he applied brakes. The pilot, who described the aircraft as having experienced a "shudder," responded that he had not applied the brakes.
The tug driver indicated that she initially believed something might be wrong with the tug; however, she proceeded with another pushback effort. After restarting the pushback she observed for the first time the landing gear of a Boeing 767 which was already located in the alleyway. The Boeing 767 was located directly behind the Boeing 737. It was then that she realized a collision had occurred.
In September of 1995, United Airlines management was aware that aircraft utilizing its gate number 77 did not have the minimum 25-foot aircraft wing tip clearance in the alleyway as required by the City of San Francisco. City personnel agreed to allow United to paint temporary aircraft lead-in lines at the gate and to allow Boeing 737 aircraft gate usage provided United "guarantee the use of wing walkers."