US safety investigators have determined that wires in the landing gear brake configuration of a United Airlines Airbus A320 that was involved in runway excursion at Jackson Hole airport in Wyoming were cross-connected, which could have played a role in the incident.
The aircraft, operated under United’s low-cost Ted banner, veered off the runway at Jackson Hole on February 25 and came to rest 35m (116ft) past the end of the runway and 43m (140ft) right of the runway centerline.
Investigators with the National Transportation Safety Board (NTSB) noted a heavy skid mark was found on the runway associated with the inboard tire of the left main landing gear.
An examination of the left main landing gear brakes revealed that the inboard and outboard wheel speed tachometer wires were cross-connected.
“Such a configuration would be likely to cause the antiskid system to use the inboard wheel speed to control the outboard braking, and vice-versa,” says NTSB. “In such a situation, it would be likely that when the inboard tire began to skid, the antiskid system would release the pressure on the outboard brake instead of the inboard brake.”
NTSB notes maintenance records indicate both main landing gear units were replaced on the incident aircraft in early February.
The board is also investigating a similar United A320 incident that occurred on October 9, 2007. In that excursion the United A320 received minor damage when it hit runway lighting at Chicago O’Hare International Airport.
Source: flightglobal.com's sister premium news site Air Transport Intelligence news
Source: FlightGlobal.com
