Cessna 172M N5129R accident near Saratoga, Wyoming

Probable cause

The pilot’s decision to attempt flight into approaching adverse weather, which led to his low-level flight, encounter with mountain obscuration and moderate turbulence, and his subsequent loss of airplane control. Contributing to the severity of the pilot’s injuries was the failure of the seat restraint assembly.

NTSB analysis

Near the time of the accident, a witness observed an airplane fly overhead in an easterly direction about 500 feet above the ground; the airplane wasn't visible until directly overhead through an opening in the low and broken clouds. The airplane continued its flight toward mountainous terrain. GPS data revealed that the airplane then conducted several 360-degree turns, which suggests that the pilot was attempting to maneuver around clouds or low visibility conditions. The airplane subsequently turned toward a nearby airport. The airplane's last recorded position revealed that it was about 900 feet above surrounding terrain in the area of the accident site. Weather conditions at the time included mountain obscuration and moderate turbulence for the area, which likely made it difficult for the pilot to maintain visual separation and the altitude necessary to remain clear of the surrounding terrain; while maneuvering, he subsequently lost airplane control. Impact damage to the airplane was indicative of a left-wing-down, near-vertical, low-speed impact with trees and terrain. A propeller strike to a large tree indicated that the engine was producing power at the time of impact.

The wreckage was located 2 days after the accident, after search efforts were halted several times due to variable emergency locator transmitter position estimates and deteriorating weather conditions. First responders reported that the pilot was found beneath the airplane's wing with a sleeping bag under his torso. The pilot was dressed in multiple layers of clothes and survival gear. Food and water was found in the airplane but was not used. The pilot's cause of death was hypothermia due to the extreme winter conditions at the time of the accident; the pilot's injuries were not severe enough to be considered fatal.

Postaccident examination of the airframe revealed that the pilot's shoulder harness failed during the accident. The stitched threading at the "Y" junction joining the shoulder strap webbing behind the pilot's head to the webbing leading to the fuselage connection had separated. The pilot's injuries suggest that he was using the three-point shoulder harness at the time of the accident and was exposed to strong deceleration forces. It is likely that if the pilot's shoulder harness had not separated, he would not have suffered the serious chest injuries and, therefore, would have been better able to use the survival gear and tactics needed to survive during the time it took for search and rescue to locate the wreckage. The investigation found that although the breaking strength of the webbing did not meet the requirements in effect at the time of the accident, it did meet the requirements in place at the time the supplemental type certificate for the seat restraint assembly was approved.

Postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR13FA138 for the full record.