NTSB -- NTSB ISSUES SECOND UPDATE ON JACKSON HOLE B-757 RUNWAY OVERRUN INCIDENT

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NTSB ADVISORY

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National Transportation Safety Board

Washington, DC 20594

January 12, 2011

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NTSB ISSUES SECOND UPDATE ON JACKSON HOLE B-757 RUNWAY

OVERRUN INCIDENT

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In its continuing investigation of the runway overrun of a

jetliner in Jackson Hole, Wyoming, the National

Transportation Safety Board has developed the following

factual information:

At about 11:38 am MT on Wednesday, December 29, American

Airlines flight 2253, a B-757-200 (N668AA) inbound from

Chicago O'Hare International Airport, ran off the end of

runway 19 in snowy conditions while landing at Jackson Hole

Airport. No injuries were reported among the 181 passengers

and crew on board.

Instrument Flight Rules (IFR) weather conditions prevailed

around the time of the incident with a ceiling of 400 feet,

light snow and visibility of 1 mile. Winds were 10 knots

from 240 degrees. Runway friction measurement data obtained

before and after the event have been provided by the Jackson

Hole Airport Authority for further evaluation by the NTSB.

In the continuing investigation, work groups have been

formed to examine the subject areas of air traffic control,

airports, meteorology, flight crew operations,

airworthiness, maintenance records, cockpit voice recorder

(CVR), flight data recorder (FDR), and airplane performance.

The NTSB systems investigator conducted testing on the

incident airplane from December 31, 2010, through January 6,

2011. Operational testing and examination was accomplished

on the spoiler/auto speed brake, air/ground, autobrake, and

thrust reverser systems. No discrepancies were found in the

air/ground, autobrake, and thrust reverser systems.

Examination of the auto speed brake mechanism in the cockpit

pedestal found that the linear actuator aft attachment was

improperly installed and was missing a bushing. This loose

connection allowed the cam to be rotated slightly relative

to the switch, which could cause the switch roller and the

notch in the cam to not always align. System operation with

this condition present is being investigated.

The maintenance group convened at the American Airlines

facility in Tulsa, Oklahoma, to review airplane logbooks.

The group focused primarily on the spoiler/speed brake,

air/ground, and thrust reverser systems. No significant

issues with any of these systems were recorded prior to the

incident, and there were no open minimum equipment list

(MEL) items at the time of the incident. The airplane was

manufactured in June 1992 and, at the time of the incident,

had accumulated 58,879 hours and 20,518 cycles. No

discrepancies were noted during the last periodic service

maintenance check conducted on December 26, 2010. The last

heavy maintenance was accomplished in October 2005. The auto

speed brake actuator was replaced in January 2008.

The CVR group convened on January 4, 2011, at the NTSB

recorder laboratory. The group completed a transcript of the

last 30 minutes of the recording and a summary of the

previous 90 minutes. The transcript will be released when

the public docket is opened.

The FDR group has begun the process of determining which of

the documented parameters are installed and should be

functional, and is checking the recorded data for validity.

The group has verified the following factual information:

* The FDR download contains the last 43.9 hours of data,

more than the required 25 hours, and includes all of

the incident flight.

* The recorded speed brake handle position indicates

that the speed brakes were manually extended by the

flight crew during the approach after which the handle

was left in the armed position until landing. The FDR

records only the speed brake handle position and not

the individual speed brake (spoiler) panel positions.

* The FDR data indicate that the aircraft touched down

at approximately 132 knots.

* At touchdown, the air/ground parameter changes to

"ground" for approximately one second and then

switches to "air" for approximately ½ second before

changing back to "ground" for the remainder of the

recording.

* During the time period when the air/ground parameter

switched back to "air," the speed brake handle

position momentarily moved toward the down position

and then returned to the armed position where it

stayed for the remainder of the recording.

* Thrust Reverser (T/R) discrete parameters indicate

that the T/Rs moved into the in-transit position

during the ½ second that the air/ground logic

parameter indicated "air."

* The T/Rs remained in the in-transit position for

approximately 10 seconds before transitioning to the

stowed position for one second. The T/Rs then moved

back to the in-transit position for an additional 6

seconds before becoming deployed.

* The T/R discrete parameters indicate that

approximately 18 seconds elapsed from the time the

T/Rs began moving until they were fully deployed.

Additionally, the team has examined security camera videos

provided by the airport as well as a video of the landing

taken by one of the passengers.

The accident docket, which will contain additional factual

information, is expected to be opened in 60-90 days. It will

be available on the NTSB website at http://go.usa.gov/rjR

RELATED INFORMATION

First investigative update (12/31/10): http://go.usa.gov/rwm

Media advisory announcing incident investigation (12/29/10):

http://go.usa.gov/rjN

Runway Safety on NTSB's Most Wanted List of Safety

Improvements: http://go.usa.gov/rTn

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NTSB Media Contact: Peter Knudson

peter.knudson@xxxxxxxx

(202)314-6100

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