Aircraft Impact Following Steep Spiral Turn

Casualties unknown • Sanona Creek, AK, US

An unidentified aircraft crashed into the ground at a near-vertical angle following a steep spiral turn while attempting a base turn to an airstrip threshold.

What happened

The aircraft was observed flying over the airstrip from the southwest at an altitude of approximately 200 to 300 feet AGL. During the flight, the pilot began a left-hand turn intended as a base turn toward the west threshold of the airstrip. This maneuver transitioned into a steep spiral turn, resulting in the aircraft impacting the ground at a near-vertical angle. At the time of the accident, winds were originating from the west at approximately 30 mph.

The investigation

The investigation revealed several significant discrepancies regarding the aircraft's documentation and configuration. The aircraft was equipped with 32x15 balloon tundra tires, but no data was available to evaluate how these tires affected the airplane's flight performance or handling envelope.

Furthermore, the aircraft lacked a registration, flight manual, weight and balance records, or Form 337 documents following a complete rebuild after the aircraft had been reported destroyed in 1989. There were also insufficient STC or FAA field approval documents for various modifications. Additionally, the investigation determined that the aircraft was at least 117 lbs over its maximum gross weight, and shoulder harnesses were not installed.

Probable cause

The aircraft's weight exceeded its maximum allowable gross weight, and there was a lack of documentation regarding flight performance with modified tires and insufficient approval for modifications.

Frequently asked questions

What happened in the 1993-09-02 Piper PA-18A-150 accident near Sanona Creek, AK?

An unidentified aircraft crashed into the ground at a near-vertical angle following a steep spiral turn while attempting a base turn to an airstrip threshold.

What aircraft was involved and where did it happen?

The accident on 1993-09-02 involved a Piper PA-18A-150, registration N4713A, operated by Garfield, Wade E., at Sanona Creek, AK.

What was the probable cause of the accident?

The aircraft's weight exceeded its maximum allowable gross weight, and there was a lack of documentation regarding flight performance with modified tires and insufficient approval for modifications.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X13278. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

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