Cessna 172K N84385 accident near Marana, Arizona

Probable cause

A total loss of engine power due to fuel exhaustion.

NTSB analysis

The pilot departed on the cross-country flight with an estimated 38 gallons of fuel onboard. While enroute, the pilot deviated from the direct route to his destination, which increased his enroute time and distance. Flight track data revealed that the airplane arrived near the planned fuel stop, but the pilot stated that he diverted to another airport when he could not activate the runway lights at his intended fuel stop. After travelling for about 3 hours, 46 minutes, a total of about 467 miles, and about 5 miles short of the airport intended to be his second fuel stop, the engine lost total power about the time that the pilot stated that the fuel quantity gauges had “dropped all the way to basically nothing.” The pilot reported that there were no mechanical malfunctions or failures that would have precluded normal operation but suspected that the airplane may have developed a fuel leak. Postaccident examination revealed no evidence of a fuel leak. Based on the available information, it is likely that the loss of power was the result of fuel exhaustion. The Owner’s Manual Cruise and Range Performance Chart revealed that with 38 gallons of fuel, the accident flight’s distance and time enroute were within the chart limits; however, the accident flight consisted mostly of low altitude maneuvering flight that were not addressed by the Owner’s Manual.

Field sobriety testing of the pilot was conducted at the scene of the accident, with no determination of impairment being made by law enforcement at that time. Toxicological testing of the pilot’s blood indicated that the pilot likely had used a cannabis product, cocaine, amphetamine, and MDMA. Although his use of these controlled substances conveyed significant risk of impairment, available evidence was insufficient to determine the precise timing of his substance use, specific impairing effects during the accident flight, or whether such effects contributed to the accident.

Text from the NTSB. Open the NTSB docket for WPR23LA241 for the full record.