LOS ANGELES, CA, USA
N388UA
Boeing 737-322
The flight was being pushed back by a tug when it contacted a lavatory service truck, which had pulled up at the rear of the airplane to service the lavatories. The airline uses one person pushback operations at this station for B737's. Under the procedure, the ground handler will walk around the airplane just before the pushback to ensure that the airplane's path is clear. Once the flight crew gives the clearance, the pushback commences without the aid of wing walkers or other safety observers. The handler assigned to this flight did his walk around after the jetway bridge had been moved back. Once he was cleared by the flight crew he leaned over the tow bar for one last look and then mounted the tractor to start the push. He did not see the lavatory service truck at any time and the lavatory driver did not verbally communicate his presence or intentions. The flight crew turned on the rotating beacon just before the aircraft started to move. During the push the handler felt resistance and stopped just as the lavatory service driver ran to the front of the airplane shouting for him to stop. Three calls had been made for lavatory service on this airplane, the last one 10 minutes prior to departure. The lavatory service driver originally assigned to handle this flight was busy. Another lavatory service driver heard the service request on the radio and responded to the airplane, arriving about 7 minutes prior to departure. When he arrived, the rotating beacon was not on, which signified to him that the pushback was not imminent. He parked his service truck under the tail of the airplane and proceeded to service the aft lavatory just as the airplane began to move and it contacted his truck. The airline's ramp operations manual states, 'Before approaching aircraft to perform last-minute servicing, at or near departure time, always establish positive verbal communication with the pushback tractor driver.'
On September 12, 1999, at 0852 hours Pacific daylight time, United Airlines flight 2528, a Boeing 737-322, N388UA, collided with a lavatory service truck during pushback from gate 84 at the Los Angeles International Airport, Los Angeles, California. The aircraft was operated by United Airlines, Inc., as a regularly scheduled domestic passenger flight under 14 CFR Part 121. The aircraft incurred substantial damage. None of the 2 ATP-licensed cockpit crew, 3 flight attendants, 81 passengers, or 5 ground service personnel were injured. The flight was originating as a nonstop flight to Oakland, California. An IFR flight plan was filed and visual meteorological conditions prevailed. According to United Airlines Flight Safety Department, the aircraft was being pushed out of gate 84 by a tug when it contacted a lavatory service truck. The damaged area on the aircraft encompassed a 60- by 60-inch section of the right rear fuselage at a point 5 feet forward of the lavatory service panel. In addition to skin damage, two stringers and two lower bell frames were bent. Documents provided by the company state that one person pushback operations are performed at the Los Angeles and San Francisco stations for Boeing model 737 and 727 airplanes. According to the procedure, the aircraft maintenance technician (AMT) designated to handle a flight will walk around the airplane just before the pushback to ensure that all personnel, equipment, and vehicles are clear of the airplane's path. Once the flight crew gives the AMT a clearance, the pushback commences without the aid of wing walkers or other safety observers. In his written statement, the AMT assigned to handle the pushback of flight 2528 said he completed his walk around of the airplane shortly before scheduled departure after the jetway bridge had been removed from the airplane's side and all vehicles, personnel, and equipment were clear. He then stationed himself beside the tractor awaiting a clearance from the flight crew. Once he had the clearance, he leaned over the tow bar for one last look and then mounted the tractor to commence the push. The AMT stated that he did not see the lavatory service truck at any time and the lavatory driver did not verbally communicate his presence or intentions. The flight crew reported that they turned on the rotating beacon just before the aircraft started to move. The AMT said he began the push and felt resistance after moving about 10 feet; he stopped the push just as the lavatory service driver ran to the front of the airplane shouting for him to stop. The written statements provided by the involved United Airlines personnel established that three calls were made to service the lavatories on the airplane, once while inbound to Los Angeles, and two additional times while parked at gate 84, at 30 and 10 minutes prior to scheduled departure. The lavatory service driver originally assigned to handle this airplane was tied up with other airplanes on the concourse. Another lavatory service driver heard the conversation on the radio, was near gate 84 and responded to the airplane. He arrived about 7 minutes prior to scheduled departure. According to his statement, when he approached the rear of the airplane, the rotating beacon was not on, which signified to him that the pushback was not imminent. He parked his service truck under the tail of the airplane and proceeded to service the aft lavatory. As he finished dumping the airplane's holding tank, it began to move and contacted his truck. He crawled out of the lift basket, ran to the front of the airplane, and shouted to the pushback tractor driver to stop the pushback. United Airlines Ramp General Operations Manual, Chapter 45-2-1, contains procedures for ground personnel to observe while approaching an airplane near departure time. A cautionary note states, "Before approaching aircraft to perform last-minute servicing, at or near departure time, always establish positive verbal communication with the pushback tractor driver." According to the written statements of the pushback tractor driver and the lavatory service driver, positive verbal communication was not established prior to commencement of the lavatory service operation.
The lavatory service driver's failure to follow established company procedures and directives. A factor in the accident was the airline's use of a one person pushback procedure.
Source: NTSB Aviation Accident Database
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