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Accident description
Last updated: 23 October 2017
Status:Final
Date:Wednesday 21 November 1990
Time:18:15
Type:Silhouette image of generic DH8A model; specific model in this crash may look slightly different
de Havilland Canada DHC-8-103
Operator:Bangkok Airways
Registration: HS-SKI
C/n / msn: 172
First flight: 1989
Total airframe hrs:3416
Cycles:2998
Engines: 2 Pratt & Whitney Canada PW120A
Crew:Fatalities: 5 / Occupants: 5
Passengers:Fatalities: 33 / Occupants: 33
Total:Fatalities: 38 / Occupants: 38
Airplane damage: Damaged beyond repair
Location:5 km (3.1 mls) SW of Koh Samui Airport (USM) (   Thailand)
Phase: Approach (APR)
Nature:Domestic Scheduled Passenger
Departure airport:Bangkok-Don Muang International Airport (BKK/VTBD), Thailand
Destination airport:Koh Samui Airport (USM/VTSM), Thailand
Flightnumber: 125
Narrative:
Flight 125 left Bangkok at 09:58 UTC with IFR clearance to Samui at FL210. Samui Tower was contacted at 10:45 and the crew were told runway 17 was the active runway and that the weather was fair with rain southwest of the field. Wind was later reported at 030 deg/10 knots and the runway was changed to runway 35. On base leg for runway 35 the flight continued ahead instead of turning right for finals. A missed approach procedure was executed with flaps still fully extended and both pilots were confused about which way to go. Samui Tower instructed them to turn left because of a mountain on the right side. BKP 125 entered an area of heavy rain and rolled to the left. Both pilots were disoriented as the aircraft continued to descend in a left wing down attitude. The aircraft eventually impacted into a coconut plantation at a 147 knots speed, 36deg nose-down and 75deg left roll.

Probable Cause:

PROBABLE CAUSE: "The pilot experienced spatial disorientation which resulted in improper control of the aircraft. Factors which contributed to accident were as follows: (1) The pilot flew the aircraft into bad weather condition which had very little or no visual reference; (2) Channelized attention occurred when all of the pilots concentration were focused on looking for the airport and neglecting to do proper cross checking or monitoring the aircraft attitude; (3) Confusion of pilots, poor teamwork or poor cockpit co-ordination in monitoring the flight instruments might contribute to loss of situational awareness and improper control of the aircraft through their false senses."

Classification:
Low visibility
Loss of situational awareness
Loss of control

Sources:
» ICAO Circular 263-AN/157 (231-245)


Photos

photo of de Havilland Canada DHC-8-103 HS-SKI
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Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Bangkok-Don Muang International Airport to Koh Samui Airport as the crow flies is 486 km (304 miles).
Accident location: Approximate; accuracy within a few kilometers.

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