Ferry Flight Deviates into Mountains During Icing Conditions

Casualties unknown • Tyonek, AK, US

A ferry flight operating under day VFR rules encountered IMC over a mountain range, deviated from its assigned airway, and crashed into terrain at high elevation.

What happened

Two pilots were conducting a ferry flight under the authority of a permit that restricted operations to day visual flight rules conditions and required a single pilot in command. Prior to departure, the crew requested and received weather information exclusively for the destination airport, which was reported as visual meteorological conditions. They did not obtain en route weather forecasts or updates.

While en route, the aircraft encountered instrument meteorological conditions over a mountainous region. Radar data indicated that upon entering the poor weather, the flight deviated from its assigned airway and appeared to follow mountain passes in an attempt to navigate through the terrain. Attempts to establish radio contact with the pilot shortly after he left his cleared route were unsuccessful.

The aircraft was located at an elevation of 10,600 feet on a mountain peak that stood at 11,413 feet. The crash site was situated approximately 30 miles south of the intended course. Weather reports from the area indicated instrument meteorological conditions with moderate to heavy icing reported shortly after the accident occurred.

Findings

The flight was operating under a ferry permit that mandated day VFR conditions and single-pilot operation, yet the crew proceeded into weather that violated these restrictions. The decision to deviate from the assigned airway into mountainous terrain while encountering moderate to heavy icing contributed significantly to the loss of control and subsequent impact with the mountain.

Safety message

Pilots operating under ferry permits must strictly adhere to the limitations of day VFR and single-pilot operations. Obtaining weather information solely for the destination is insufficient; en route weather conditions must be evaluated, and deviations into IMC or icing conditions are extremely hazardous without proper instrumentation and training.

Probable cause

The pilot's decision to continue the flight into instrument meteorological conditions while operating under a ferry permit that restricted flights to day VFR, resulting in controlled flight into terrain due to loss of situational awareness and icing.

Frequently asked questions

What happened in the 1988-04-27 Beech C55 accident near Tyonek, AK?

A ferry flight operating under day VFR rules encountered IMC over a mountain range, deviated from its assigned airway, and crashed into terrain at high elevation.

What aircraft was involved and where did it happen?

The accident on 1988-04-27 involved a Beech C55, registration N2730T, operated by Galena Air Service, at Tyonek, AK.

What was the probable cause of the accident?

The pilot's decision to continue the flight into instrument meteorological conditions while operating under a ferry permit that restricted flights to day VFR, resulting in controlled flight into terrain due to loss of situational awareness and icing.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X25364. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

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