Pilots of an American Airlines Boeing 757-200 that overran the runway on landing in Jackson Hole Wyoming in December 2010 could not deploy the aircraft's thrust reversers, according to a transcript from the cockpit voice recorder recently released by the US National Transportation Safety Board (NTSB).
The aircraft came to a stop 107m (350ft) past the end of the runway in hard-packed snow.
Earlier in its investigation the NTSB determined the thrust reversers were not fully deployed until 18 seconds after touchdown.
Through operational testing conducted by the investigators no discrepancies were found in the air/ground sensor and thrust reverser system. However, an examination of the auto speed brake mechanism in the cockpit showed an improperly installed component with a missing bushing.
After the overrun the captain told the first officer, who was operating the aircraft, "we did everything right, we didn't get the thrust reversers".
The first officer also had problems with the aircraft's brakes, and told the captain, "they did not release". He also stated: "We were sliding and uh I couldn't get the thrust reverser would not come out they were stuck."
In communication with passengers one of the pilots stated, "thrust reversers didn't come out. I've been here 19 years and we got virtually no assist on the braking. I'm not sure why the brakes, ah, they didn't take and the thrust reversers didn't come on".
Prior to the landing after the captain received a briefing from the Jackson Hole automatic terminal information service, the captain briefed the first officer on the field conditions and braking action.
He also expressed concern about conditions of the last third of the runway. A Challenger that had previously landed at the airport reported braking action in the first two-thirds of the runway as good and poor in the last third, said NTSB. The runway condition was reported as thin loose snow over patchy thin snow and ice.
Shortly after the incident NTSB banned American from the investigation after carrier personnel downloaded the flight data recorder. American said it downloaded the data as part of its normal safety investigation.
Source: Air Transport Intelligence news
