Event Details

Title:Aircraft incident to LN-RLF at the Växjö/Kronoberg airport, G County, Sweden On June 23, 1999
Micro summary:An omission of arming the spoilers results in anti-skid failure and a runway overrun.
Event Time:1999-06-23 at 1655 UTC
File Name:1999-06-23-SE.pdf
Publishing Agency:Swedish Accident Investigation Board (AIB)
Publishing Country:Sweden
Report number:RL 2000:38e
Site of event:Växjö/Kronoberg airport
Latitude/Longitude:5655N 1443E
Departure:Stockholm-Arlanda Airport, Marsta, Sweden
Destination:Kronoberg Airport (Växjö/Kronoberg), Kronoberg, Sweden
Airplane Type(s):McDonnell Douglas DC-9-82 (MD-82)
Flight Phase:Landing
Type of flight:Revenue
Serious Injuries:0
Other Injuries:0
Executive Summary:An SAS MD-82 aircraft departed the Stockholm/Arlanda airport on June 23, 1999 on a scheduled passenger flight to the Växjö/Kronoberg airport. The weather was good however the runway was reported wet from a previous rain shower. The commander, who was the flying pilot sitting in the left pilot seat, chose to perform an ILS1 approach to runway 19, selected the ABS2 to medium and planned to use engine reverse.

The touchdown was normal and engine reverse was selected. Deceleration appeared normal in the beginning however the commander felt that the aircraft did not continue to properly decelerate. He re-checked the ABS position several times, increased reverse thrust, selected position maximum on the ABS, and finally increased engine reverse to maximum. The aircraft then began to decelerate much better but however it went off the runway end with a speed of about 10-20 knots. The aircraft came to a halt with the tail 41 m. outside the runway edge. Nobody onboard was injured.

The first officer stated that he touched the brake discs shortly after the incident and determined that they were cold.

SHK was able to determine with the help of the aircraft recorders that a normal landing had occurred and that the speed reduced to about 60 knots, when engine reverse increased to maximum thrust. The read out revealed that the landing spoilers had not deployed and that no wheel braking had taken place.

The aircraft’s ABS system measures the amount of retardation during the rollout and regulates braking according to the deceleration rate selected on the ABS switch. The ABS is however not activated until the spoilers are deployed. The arming of the spoilers for automatic deployment upon landing is checklist item performed by the pilot in the left seat and is to be confirmed by the right seat pilot during the reading of the checklist. This checklist item is read when landing flaps are selected and the flying pilot orders completion of the landing checklist. It was not possible to determine whether this checklist had been read or not as a recording was not available from the CVR.

Unlike the takeoff phase, there is no indication during landing that the ABS is not working due to failures such as the spoilers not being activated. It is the duty of the non-flying pilot to visually confirm automatic deployment of the spoilers after touchdown and to verbally communicate this to the flying pilot. Should this not occur automatically then they must be manually deployed.

No technical fault was found with the aircraft braking system after investigation by SHK.

The commander felt certain that the spoilers had been armed for automatic deployment upon landing which would enable the ABS system to function correctly. The data on the flight recorder however does not indicate that this was the case. The statements given by both pilots to SHK support all the data registered on the flight recorder except that the activation of the spoilers for automatic deployment and the confirmation of this must have been forgotten. If this mistake had been discovered during the landing rollout then the commander could have instead used normal manual braking and the aircraft would in most probability stayed on the runway. The non-flying pilot must have also forgotten to verbally confirm automatic spoiler deployment after touchdown.

SHK considers that the present aircraft design that warns the pilot against failure to activate the automatic spoiler deployment system before takeoff but not for landing is not logical. A pilot performed procedure has instead compensated for this design fault.

The incident was most probably caused through the failure to apply good Crew Resource Management (CRM) techniques after ordering the final landing flap setting, resulting in the spoilers not being armed. The first officer also failed to report that the spoilers had not automatically deployed after touchdown. As the spoilers had not been armed to deploy the automatic braking system was never activated. Engine reverse was the only stopping aid used after touchdown, this being insufficient to stop the aircraft before the end of the runway.

The incident occurred with two commanders making up the cockpit crew, with the more experienced acting as the first officer. Experience has shown that this composition has certain risk factors attached to it.
Learning Keywords:Operations - Braking Issues (General)
Operations - Runway Overrun
Operations - Slippery Runway, Taxiway, Apron
Systems - Landing Gear
Close match:Aircraft Incident at Joensuu airport, Finland on 11 April 1997
Runway excursion, Piedmont Airlines Flight 467, Boeing 737-222, N752N, Charlotte Douglas International Airport, October 25, 1986
Birdstrike and runway overrun, Northwest Airlines, Inc., Boeing 747-151, N602US, Miami, Florida, December 15, 1972
Runway overrun, Eastern Air Lines, Inc., McDonnell-Douglas DC-9-31, N8967E, Akron-Canton Regional Airport, North Canton, Ohio, November 27, 1973
Runway overrun, Piedmont Airlines, Boeing 737, N751N, Greensboro, North Carolina, October 28, 1973
Runway overrun, Boeing 737-130, Washington National, February 20, 1996
Runway overrun following brake failure, Boeing 737-247, Atlanta, January 19, 1995
Runway excursion, Royal Air Maroc Boeing 747-200 CN-RME, Dorval/Montreal International Airport, uebec, 23 July 2000


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