Cessna 172 N84249 accident near Chatsworth, Georgia

Probable cause

The pilot's inadequate flight planning and in-flight fuel management resulting in a total loss of engine power due to fuel exhaustion. Contributing to the accident was the operator's failure to ensure aircraft records pertaining to engine modifications and fuel burn rates were available to flight crewmembers.

NTSB analysis

Prior to departure, the pilot filed an instrument flight rules (IFR) flight plan to his destination airport and calculated a fuel burn rate of 9 gallons of fuel per hour. Approximately 2 hours and 30 minutes after departure, the pilot canceled his IFR flight plan with the air traffic controller without giving a reason and changed his destination airport. One minute later, the pilot declared an emergency with air traffic control, reporting his engine had failed. Witnesses in the vicinity of the crash site observed the airplane flying at tree top level, and reported they could not hear the engine running. The airplane made a steep right turn, struck the top of a tree, and collided with the ground.

Examination of the airframe and engine revealed no anomalies. The right main fuel tank was not ruptured and contained 1 quart of fuel. The left main fuel tank was not ruptured and contained 2 1/2 gallons of fuel, 2 of which were considered unusable fuel. Review of the airplane logbooks revealed the engine horsepower had been increased to 160 horsepower, and the airplane's fuel burn rate was increased due to a modification by a Supplemental Type Certificate (STC) 8 years prior to the accident. A copy of the STC was not located in the airplane wreckage. The registered owner reported the pilot had received instruction on the STC; however, no documentation was provided substantiating this instruction. He further stated the STC only increased the fuel burn rate for the first 5 minutes of flight at takeoff power. Review of the engine Operator's Manual revealed the maximum fuel usage at full power, is about 13.6 gallons per hour. At 82 percent power the fuel burn rate is about 11.25 gallons per hour.

Text from the NTSB. Open the NTSB docket for ERA10FA502 for the full record.