Accident Sequence
The aircraft was dispatched to a restricted airport with a 3900-foot runway. A NOTAM indicated 3 feet of standing water on the north end of the runway. A SIGMET was in effect for moderate to severe turbulence below 10,000 feet due to strong low-level wind and associated wind shear.
The captain executed a shallow overwater approach to Runway 12, which had a near-vertical 70-foot bluff skirting its left edge, approximately 106 feet from the runway centerline. During the final approach, the captain noted variable wind conditions and a sudden 15-knot increase in indicated airspeed (IAS) due to wind shear. He continued the approach, but the aircraft settled and touched down 72 feet short of the runway. The left main landing gear struck a log (washed onto shore) and a large rock, then collapsed after the aircraft bounced and landed on the runway.
Environmental Conditions
Unpredictable winds and downdrafts were reportedly prevalent at the airport. The official 1349 ADT wind was from 160 degrees at 8 knots, but at the approach end of the runway, the wind was reported as coming over the bluff and gusty. The captain was blinded by sunglare off the water and was not wearing sunglasses.
Aerodrome Information
The FAA had granted MarkAir an exemption to operate at Unalaska without overrun or safety areas. There was no VASI at the approach end of Runway 12. The owner of the airport (State of Alaska) had delayed improvements due to funding problems. The required dry landing field length had been computed to be 3,700 feet.
This was the captain's 10th landing at Unalaska.