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Accident description
Last updated: 18 October 2017
Status:Final
Date:Wednesday 25 September 1985
Time:13:33
Type:Silhouette image of generic B732 model; specific model in this crash may look slightly different
Boeing 737-2X6C
Operator:MarkAir
Registration: N674MA
C/n / msn: 23292/1113
First flight: 1985
Total airframe hrs:614
Engines: 2 Pratt & Whitney JT8D-17A
Crew:Fatalities: 0 / Occupants: 4
Passengers:Fatalities: 0 / Occupants: 17
Total:Fatalities: 0 / Occupants: 21
Airplane damage: Substantial
Airplane fate: Repaired
Location:Unalaska Airport, AK (DUT) (   United States of America)
Phase: Landing (LDG)
Nature:Domestic Scheduled Passenger
Departure airport:Anchorage-Ted Stevens International Airport, AK (ANC/PANC), United States of America
Destination airport:Unalaska Airport, AK (DUT/PADU), United States of America
Narrative:
The Boeing 737-200 aircraft was dispatched to a restricted airport with a 3900 ft runway and notamed: 3 inch standing water on north end of runway. A sigmet was in effect for moderate to severe turbulence below 10,000 feet due to strong low level wind and associated windshear. The captain made a shallow overwater approach to runway 12, which had a near vertical 70 ft bluff skirting its left edge, approx 106 feet from the runway centerline. On final approach, the captain noted variable wind conditions and a sudden 15 kt increase in IAS due to windshear. He continued the approach, but the aircraft settled and touched down 72 feet short of the runway. The left hand main gear hit a log that was washed onto shore and a large rock, then collapsed after the aircraft bounced and landed on the runway. Unpredictable winds and downdrafts were reportedly prevalent at this airport.
Official 13:49 ADT wind was from 160 degrees at 8 kts, but at the approach end of runway, wind was reported coming over the bluff and was gusty. The FAA had granted MarkAir exemption to operate at Unalaska without overrun/safety areas. There was also no VASI at the approach end of runway 12. The owner (State of Alaska) delayed improvements due to funding problems. This was the captain's 10th landing at Unalaska. The required dry landing field length was computed to be 3700 feet.

Probable Cause:

PROBABLE CAUSE(S):
planning/decision..improper..company/operator management
compensation for wind conditions..inadequate..pilot in command
proper touchdown point..not attained..pilot in command

CONTRIBUTING FACTORS:
insuff standards/requirements,operation/operator..FAA(organization)
airport/facilities..inadequate
other airport/runway maintenance..inadequate
inadequate surveillance of operation..FAA(organization)
inadequate surveillance of operation..other govt organization
light condition..sunglare
visual/aural perception..pilot in command
airport facilities,visual apch slope ind(vasi)..unavailable
weather condition..unfavorable wind
weather condition..windshear
lack of familiarity with geographic area..pilot in command
terrain condition..rough/uneven
terrain condition..loose objects

Classification:
Windshear/downdraft

Sources:
» NTSB


Follow-up / safety actions

NTSB issued 2 Safety Recommendations

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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 Anchorage-Ted Stevens International Airport, AK to Unalaska Airport, AK as the crow flies is 1261 km (788 miles).

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