On July 17, 2004, a Cessna 170B (registration N4588C) was involved in an aviation accident near Willow, AK. Investigators recorded the probable cause as: The pilot's failure to maintain adequate airspeed, which resulted in an inadvertent stall while maneuvering, and a collision with trees and terrain during an uncontrolled descent. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A private pilot and three passengers were on a visual flight rules (VFR) trip when witnesses observed the airplane performing turns at low altitude before it nosed down and struck trees and soft ground.
Accident Overview
A private certificated pilot was returning from a round-robin VFR personal flight with three passengers. The flight was paralleling a rural highway. A witness observed the airplane about 30 feet above the trees, southbound on the west side of the highway. The nose of the airplane appeared slightly up. It then made a smooth right turn of about 180 degrees toward the north, nosed down about 45 degrees, and descended from view into the trees.
Another witness reported observing the airplane northbound at a low altitude on the west side of the highway. The airplane appeared to be making a right banking turn and then nosed down toward the trees. The airplane began a 3/4 spiral turn downward and disappeared into the trees.
Impact and Wreckage
On-site investigation disclosed that the airplane collided with several trees and then struck soft ground in about a 45-degree nose-down attitude. The cabin floor was oriented about 45 degrees to the right. Numerous broken tree limbs were observed about 50 feet above the impact site. The empennage was separated from the main fuselage about the forward attach point of the vertical stabilizer and was located about 20 feet north of the main impact site.
Engine Examination
An examination of the engine revealed no evidence of any preimpact mechanical malfunctions.