20060322004329I

(-23) Us airways inc., flight #944, philadelphia pa to Boston ma was disembarking passengers at Boston's us airways gate B-6 when the jet bridge collapsed hitting the L-1 door of aircraft N721UW (A-319-112), injuring one us airways mechanic and one passenger at 1000 EST, 03/22/06. One us airways mechanic injured his shoulder and one passenger injured his neck when he struck the ceiling of the jet bridge. Damage to the aircraft was limited to the L-1 door, associated hardware, and control rods. The nose gear was later inspected for side load stress with no defects noted. The L-1 door airframe was inspected and the L-1 door was replaced. The aircraft has been returned to service. From: privacy data omitted (massport operations shift manager) at 1011 EST this date, we were advised that massport fire/rescue was responding to an unknown accident involving a jet bridge at us airways gate 6. We responded to gate B-6 and observed the jet bridge control wheels twisted, and the right wheel was up under the bridge floor. We also observed several 5 to 6 inch bolts that appeared to have been sheared off the jet bridge, apparently from extreme stress or some other failure (eight total). The nuts remained attached to the bolts and they were sheared approximately half way down the length of the bolt. As we began to look further, we observed that the jet bridge was actually resting on the open aircraft's cabin door of N721UW (A-319-112), and the L-1 door was essentially holding the jet bridge up. Within minutes FAA flight standards and the state police were on the scene. We spoke with the us airways jet bridge operator privacy data omitted who reported that he was just operating the jet bridge as he had done so many times in his 23 years with us airways, and he felt it drop out from under him. Moments later a us airways coworker entered the jet bridge with a sheared bolt in his hand and told privacy data omitted to get out of the jet bridge. The aircraft was in the process of disembarking passengers. Of the one hundred passengers twenty were not able to deplane due to the collapse of the jet bridge. The twenty passengers and five crew were deplaned from the rear of the aircraft using the mobile stair truck from massport fire/rescue. Within a few minutes a command group was established and an action plan was formulated. It was decided that a crane needed to be employed to lift the jet bridge to a point where they could move the aircraft away from the jet bridge without causing further damage. A 185-TON crane from shaunessy crane service in south Boston, responded to the airport along with a rigging team to make the lift. The crane arrived at the airport at 1136 EST. Shaunessy inc., assessed the scene and a briefing on the details of the lift was conducted with the command group. The lift began at 1333L and was complete including removal of the aircraft at 1343 EST. The extent of the damage was limited to just the L-1 door. No damage to any other aircraft structure was found. The cause of the jet bridge failure was thought to be a malfunctioning jackscrew drive chain, stuck contactor on the left motor or a broken limit switch (s) on the right stabilizer but further investigation will be needed to be certain as to the actual cause. At 1426 EST the jet bridge was secured on a maintenance stand and all units secured with the exception of the rigging crew and the crane. They secured their equipment, and were escorted off the air operations area (AOA) at 1551 EST. Inspectors statement: it appears at this point in the investigation that the chain that is connected tothe motor that raises and lowers the jet bridge sheared and when it did the motor (self leveling device) could no longer control the jet bridge. There are safety switches in the motor but once the chain separated the jackscrew on the right side was free to move and it went all the way up while the left jackscrew and chain remained down. This caused all eight bolts to shear causing the two wheels come off and rack upward. It seems that in the last 2-3 weeks united airlines gse has been contracted (under agreement) to start performing "preventative maintenance" (pm) for us airways jet bridges. This jet bridge was manufactured by FMC corporation/jet way systems and is approximately 10 years old. It appears that us airways inc. has been neglecting pm on their jet bridges for the last few years in Boston. Their jet bridges have not been on a pm program for a long time according to us airways personnel/united gse. They have only been repairing them as they break. According to an FMC representative who inspected this jet bridge he found four areas of concern. There were two pre-existing broken bolts holding the two wheels in place on the jackscrew floor plates. There were non-standard (not FMC parts) arms on the limit switches and bypass switches. The brake(s) on the motors had not been maintained. The drive chains that are connected to the jackscrews had not been maintained. The drive chains have a ninety-day inspection requirement. Us airways have inspected their other jet bridges and have found similar problems. Us airways have their jet bridges on a rigid pm program as of last week and plan to have all jet bridges inspected every ninety days in Boston.