Incident Overview
On November 2, 2010, at 1027 central daylight time, a Bombardier CL-600-2B19 (registration N709BR) operated by SkyWest Airlines as flight 1020 was struck by an unoccupied United Airlines pickup truck on the ramp at O'Hare International Airport (ORD), Chicago, Illinois. The aircraft had pushed back from gate F2 and stopped, after which the crew saw the pickup truck moving rapidly in reverse and stopped the airplane. The truck, which was unoccupied, impacted the left side of the aircraft's nose. No injuries were reported among the 2 cockpit crew members, 1 cabin crew member, and 34 passengers. The airplane sustained substantial damage to four stringers and the forward bulkhead.
Sequence of Events
The pickup truck had been driven to the terminal building at gate F2D. The driver stated that he put the truck in park and exited with the engine running, intending to be away only a short time. He did not apply the parking brake. Upon returning, he found the truck under the nose of the airplane. Surveillance video from two vantage points showed the airplane stopped between the F and G concourses. The blue pickup truck crossed the ramp from right to left, then approximately 18 seconds later backed away from the terminal. The truck traveled about 100 to 150 feet in front of the airplane, made a 180-degree turn while reversing, and headed toward the airplane, which stopped just before impact.
Postaccident Inspection
After the accident, United Airlines personnel confirmed that nothing inside the truck was changed other than turning off the ignition. Photographs showed the gear shift lever positioned between P (park) and R (reverse). The truck, a 2001 Ford Ranger standard cab (United identifier PI1574), had 35,211 miles and 3,816.7 hours on its meter. During hoisting and testing, the gear shift lever remained between park and reverse. When the ignition was turned on, the rear wheels could be turned by hand, back-up lights were not illuminated, and the engine could not be started, indicating the transmission was not in park. Moving the gearshift lever toward park required several attempts before the transmission locked into park, allowing the engine to start. When the truck was lowered and the engine started, moving the gearshift to park and releasing brakes caused the vehicle to remain stationary for 2 to 3 seconds then move in reverse. This was repeated several times. The shift cable adjustment procedure from the 2001 Ford Ranger Service Manual was performed, resulting in a 3/16-inch adjustment. After adjustment, the transmission functioned reliably in park, reverse, neutral, and drive, but could not be placed in first or second gear. The inspection also revealed that the parking brake cable was disconnected where the split occurs for each rear wheel, and the right front tire was excessively worn on its inside edge.
Maintenance Records
The truck's last B check (a preventive maintenance inspection) was completed on April 26, 2010, with a meter reading of 3,233.0 hours (583.7 hours prior to the accident). The work order indicated "B/CK/COMPLETE" and listed several repairs: replacement of rear brakes, wheel cylinders, battery, upper control arms, stabilizer links, tires, spark plugs, front brake pads and rotors, rear brake cables, and bulbs. The parking brake cable was noted as frozen and replaced.
Procedural Context
The United Airlines Ramp Operations Manual requires that motorized equipment not in use be parked in designated areas, placed in neutral, parking brake set, lights off, and engine turned off. The Anti-Idling Policy prohibits leaving any motorized vehicle running while unattended. User checks must be performed at least once per shift, including checking brakes and controls. The Chicago Airport System's Ground Motor Vehicle Operation Regulations Manual requires vehicles to back into designated parking areas and prohibits leaving vehicles unattended with the motor running unless weather or operational conditions dictate otherwise. Parking brakes must be engaged when the vehicle is left unattended. The truck driver passed a test on these regulations on November 21, 2008.
Aftermath
Following the accident, United Airlines inspected all ground vehicles at ORD, resulting in 8 of 111 vehicles being taken out of service for repairs. United also implemented several changes: a service vehicle user check audit program, a compliance audit program for user checks, a Maintenance Management Program to analyze part failures, a Maintenance Planner position, review and revision of user check procedures, continual evaluation of parking areas, and enforcement of the parking brake policy when vehicles are left unattended.