ERA10FA048 · Cessna 172S

The airplane departed and climbed straight ahead to an altitude of about 600 feet before it began a left turn to the crosswind leg of the traffic pattern. It continued on a flight path toward hundreds of square miles of unlit, national forest land with the moon just above the horizon and behind the airplane. The airplane reached an altitude of about 1,000 feet as it turned from the crosswind leg to the downwind leg, and then descended in a continuous left arc toward the airport. The air traffic tower controller perceived the descent immediately and transmitted the airplane's registration number over the radio. One of the pilots responded by restating the number in business-like tone and there were no further communications from either pilot. Examination of the trees and airplane damage along the wreckage path was consistent with a shallow, wings-level, high-speed descent that suggested either one or both pilots nearly recovered control of the airplane during the last several seconds of descent to ground contact. A postaccident examination of the airframe and engine revealed no mechanical malfunctions or failures that would have precluded normal operation. Federal Aviation Administration guidance indicates that spatial disorientation can occur when there is no natural horizon or surface reference, such as a night flight in sparsely populated areas similar to that of the accident conditions.

Verbatim NTSB analysis and probable cause from the NTSB dataset