NTSB Identification: ANC93LA046.
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Accident occurred Saturday, March 20, 1993 in DRIFT RIVER, AK
Probable Cause Approval Date: 05/17/1994
Aircraft: PIPER PA-22, registration: N72999
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

DURING THE PILOT'S FIRST ATTEMPT TO FLY THROUGH LAKE CLARK PASS, HE MISTAKENLY TURNED UP THE WRONG VALLEY. WHEN THE ALREADY POOR FLIGHT VISIBILITY CONTINUED TO DETERIORATE, HE BEGAN A 180 DEGREE TURN TO GET OUT OF THE VALLEY, DURING WHICH HE ENTERED WHITEOUT CONDITIONS. WHEN HE SAW MOUNTAINS ON BOTH SIDES, HE KNEW THAT HE HAD MISSED THE TURN OUT OF THE VALLEY. WITH NO DEPTH PERCEPTION ON WHICH TO ESTIMATE HIS ALTITUDE ABOVE THE GROUND, HE APPLIED FULL ENGINE POWER AND MAINTAINED THE BEST CLIMB ATTITUDE. VERY SOON AFTERWARD THE AIRPLANE COLLIDED WITH, AND NOSED OVER ON, A GLACIER. DURING THE PREFLIGHT WEATHER BRIEFING THE PILOT WAS TOLD THAT LAKE CLARK PASS WAS FORECAST TO BE MARGINAL VFR TO IFR.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

THE PILOTS INADVERTENT VFR FLIGHT INTO IMC CONDITIONS. FACTORS WERE THE RISING TERRAIN AND THE WHITEOUT CONDITIONS.

Full narrative available

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