Improper installation of brake parts was a factor in an American Airlines plane overshooting a runway while landing at Dallas-Fort Worth International Airport in February, according to an aviation investigation preliminary report by the National Transportation Safety Board.
The 104 passengers and crew members, traveling from Ronald Reagan Washington National Airport in Arlington, Virginia, deplaned the Boeing 737-800 at DFW and were bused to a terminal after the plane experienced a brake malfunction Feb. 10, according to the NTSB. No one was injured.
The pilot and the captain initially reported that touchdown was normal, with no directional control issues. But shortly after touchdown, the crew saw the automatic brake disarm light turn on and the brakes failed to engage. This required the crew to manually brake by applying pressure to the pedals while deploying the aircraft’s thrust reversers — an additional way to decelerate a flight while landing — according to the investigation.
The airplane then began to decelerate with the thrust reversers but at a slower pace and the pilot indicated that the brakes were not working correctly, the report says. When approaching a taxiway, the ground speed of the flight was higher than expected, the NTSB reported. The captain called the DFW airport tower and said, “American 1632, total brake failure, we are departing the end of runway 17L, roll crash fire rescue,” according to the investigation.
The plane then came to a stop after passing the runway’s threshold lights, the captain reported.
Data reviewed by the NTSB shows that the auto brake applied momentarily transitioned from “No Auto Brake” to “Auto Brake” before finally going back to “No Auto Brake” for the remainder of the landing.
According to the NTSB’s investigation, American Airlines completed a project on Feb. 6 that replaced the steel brakes on the Boeing 737 with carbon brakes and wheel assemblies per an engineering order.
A post-incident troubleshooting and inspection of the aircraft’s brake control system determined that hydraulic lines — hoses that carry hydraulic fluid, oil, fuel and air and can perform at high pressures — were improperly reconnected after the carbon brakes were installed, the report says.
The troubleshooting also found wiring in the plane’s wheel speed transducers — which measure the speed of rotation of the aircraft’s wheels for braking control — were incorrectly installed.
American Airlines, the Federal Aviation Administration, Boeing and the Transport Workers Union – International Association of Machinists also assisted the NTSB.
The investigation is ongoing.
