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Difference between revisions of "SF34, Lappeenranta Finland, 2008"

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(Created page with '==Description== On 31 January 2008 a Saab 340B being operated by Czech airline Job Air on a scheduled passenger service from Helsinki to Lappeenranta under a wet lease c…')
 
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==Investigation==
 
==Investigation==
 
An Investigation was carried out by the Accident Investigation Board Finland. It was found that the First Officer had been [[PF]] for the approach and landing. There was a light (5 knot) crosswind from the right, there were no runway centre line lights and approximately 10 mm of fresh snow covered the 33 metre cleared width of the 60 metre wide runway and obscured the centre line markings. The diagram below taken from the official Report shows the disposition of snow on the runway. ATC informed the approaching aircraft that the estimated braking action was poor but did not mention the restricted runway width or the snow banks.
 
An Investigation was carried out by the Accident Investigation Board Finland. It was found that the First Officer had been [[PF]] for the approach and landing. There was a light (5 knot) crosswind from the right, there were no runway centre line lights and approximately 10 mm of fresh snow covered the 33 metre cleared width of the 60 metre wide runway and obscured the centre line markings. The diagram below taken from the official Report shows the disposition of snow on the runway. ATC informed the approaching aircraft that the estimated braking action was poor but did not mention the restricted runway width or the snow banks.
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[[File:Disposition of snow on RWY SF34 Lappeeranta FI.jpg|none|thumb|500px|Disposition of snow on the runway during the event]]
  
 
Touch down occurred some 10 metres to the left of the runway centre line with a light crosswind from the right.  As the aircraft began to drift left, the left main landing gear penetrated the snow bank 150 m into the landing roll and the right main landing gear 240 m into the landing roll respectively. As this was about to happen, reverse pitch was applied to slow the aircraft down and the right engine failed probably because of ingested snow flung from the nose landing gear when it penetrated the snow bank. With the loss of the right engine braking effect, and with reverse pitch still effective, the aircraft nose turned further left and the aircraft skidded off the runway altogether. It was considered that the fact that the control column had been pulled rearwards had contributed to the tendency of the aircraft to turn left and it stopped at almost a 90° angle to the runway.
 
Touch down occurred some 10 metres to the left of the runway centre line with a light crosswind from the right.  As the aircraft began to drift left, the left main landing gear penetrated the snow bank 150 m into the landing roll and the right main landing gear 240 m into the landing roll respectively. As this was about to happen, reverse pitch was applied to slow the aircraft down and the right engine failed probably because of ingested snow flung from the nose landing gear when it penetrated the snow bank. With the loss of the right engine braking effect, and with reverse pitch still effective, the aircraft nose turned further left and the aircraft skidded off the runway altogether. It was considered that the fact that the control column had been pulled rearwards had contributed to the tendency of the aircraft to turn left and it stopped at almost a 90° angle to the runway.

Revision as of 14:50, 11 August 2010

Description

On 31 January 2008 a Saab 340B being operated by Czech airline Job Air on a scheduled passenger service from Helsinki to Lappeenranta under a wet lease contract for a Company called ‘Fly Lappeenranta’ which was not an aircraft operator. During the night landing at Lappeenranta, it departed the left side of the runway after touch down in normal visibility with snow falling. Propeller damage was caused when an attempt was then made to return the aircraft to the runway after the excursion. None of the 16 occupants was injured.

Investigation

An Investigation was carried out by the Accident Investigation Board Finland. It was found that the First Officer had been PF for the approach and landing. There was a light (5 knot) crosswind from the right, there were no runway centre line lights and approximately 10 mm of fresh snow covered the 33 metre cleared width of the 60 metre wide runway and obscured the centre line markings. The diagram below taken from the official Report shows the disposition of snow on the runway. ATC informed the approaching aircraft that the estimated braking action was poor but did not mention the restricted runway width or the snow banks.

Disposition of snow on the runway during the event

Touch down occurred some 10 metres to the left of the runway centre line with a light crosswind from the right. As the aircraft began to drift left, the left main landing gear penetrated the snow bank 150 m into the landing roll and the right main landing gear 240 m into the landing roll respectively. As this was about to happen, reverse pitch was applied to slow the aircraft down and the right engine failed probably because of ingested snow flung from the nose landing gear when it penetrated the snow bank. With the loss of the right engine braking effect, and with reverse pitch still effective, the aircraft nose turned further left and the aircraft skidded off the runway altogether. It was considered that the fact that the control column had been pulled rearwards had contributed to the tendency of the aircraft to turn left and it stopped at almost a 90° angle to the runway.

Runway friction was measured approximately one hour after the occurrence and the results were 0.17 / 0.17 / 0.18. The Investigation believed that runway friction at the time of the occurrence was better than at the time of the post accident measurement because subsequent wet snowfall was likely to have degraded friction.

It was noted that the flight crew had very little experience in local winter operations or with the runway winter maintenance procedures in use.