Sunday, February 24, 2019

Fuel Exhaustion: Bell 47G-2A, N9526; accident occurred August 20, 2017 at St. Marys Municipal Airport (KOYM), Elk County, Pennsylvania

The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entity:

Federal Aviation Administration / Flight Standards District Office; Pittsburgh, Pennsylvania

Aviation Accident Final Report - National Transportation Safety Board:

Investigation Docket - National Transportation Safety Board:

Location: St Marys, PA
Accident Number: ERA17LA285
Date & Time: 08/20/2017, 1200 EDT
Registration: N9526
Aircraft: BELL 47G
Aircraft Damage: Substantial
Defining Event: Fuel exhaustion
Injuries: 1 None
Flight Conducted Under: Part 91: General Aviation - Instructional 


The student pilot stated that he departed in the helicopter with 37 to 42 gallons of fuel on board; however, he had only used an average fuel burn for his endurance estimates and did not make adjustments for pressure, temperature, or other performance metrics. He indicated that, about 2 hours into the flight, the helicopter "ran out of fuel." He performed an autorotation to a grassy lot and the helicopter landed hard, which resulted in structural damage. Examination of the wreckage revealed that the fuel system was intact, that both fuel tanks were undamaged, and that each tank contained about 1 gallon or less of fuel, which was consistent with the unusable fuel quantity for each tank. The student pilot reported that there were no preimpact mechanical malfunctions or failures that would have precluded normal operation of the helicopter. Thus, because the student did not account for the pressure, temperature, and other performance metrics for his preflight calculations or in-flight fuel monitoring, he did not have sufficient fuel on board to complete the flight.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The student pilot's inadequate prefight planning and en route fuel management, which resulted in fuel exhaustion and a total loss of engine power.


Fuel - Fluid level (Cause)

Personnel issues
Decision making/judgment - Pilot (Cause)
Fuel planning - Pilot (Cause)

Factual Information 

On August 20, 2017, at 1200 eastern daylight time, a Bell 47G-2A, N9526, was substantially damaged during a hard landing at St Marys, Pennsylvania. The student pilot was not injured. The helicopter was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91 as a local, solo-instructional flight. Day, visual meteorological conditions prevailed at the time, and no flight plan was filed. The flight originated at St Marys Municipal Airport (OYM), St Marys, Pennsylvania about 1000.

The pilot reported that he arrived at OYM and performed his preflight inspection. He determined that the fuel tanks contained between 25 and 30 gallons of fuel, and then he added 12 gallons before the flight. He departed the airport and flew for about 2 hours when the helicopter "ran out of fuel." He performed an autorotation to a level, grassy lot and the helicopter landed hard. He exited the helicopter and was met by first responders. The pilot reported there were no preimpact mechanical malfunctions or anomalies that would have precluded normal operation of the helicopter.

An inspector with the Federal Aviation Administration reported that the helicopter came to rest upright in a grassy lot, about 2.6 miles west of OYM. The fuselage was structurally damaged. The landing gear skids were spread and forced up, against the fuselage. The main rotor blades were bent. There was no fire.

The inspector examined the fuel system and determined that both fuel tanks were intact and undamaged. The fuel lines remained in place and there were no fuel leaks. He estimated that both fuel tanks contained 1 gallon or less of fuel, which was the unusable fuel quantity for each tank.

The pilot also reported that he used an average fuel burn for estimating his fuel status, with no adjustment for pressure, temperature, or other performance metrics.

History of Flight

Prior to flight
Preflight or dispatch event

Fuel exhaustion (Defining event)

Off-field or emergency landing


Hard landing

Pilot Information

Certificate: Student
Age: 60, Male
Airplane Rating(s): None
Seat Occupied: Right
Other Aircraft Rating(s): None
Restraint Used: 5-point
Instrument Rating(s): None
Second Pilot Present: No
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 3 Without Waivers/Limitations
Last FAA Medical Exam: 12/12/2016
Occupational Pilot: No
Last Flight Review or Equivalent: 07/09/2017
Flight Time:   57 hours (Total, all aircraft), 57 hours (Total, this make and model), 34 hours (Pilot In Command, all aircraft), 20 hours (Last 90 days, all aircraft), 3 hours (Last 30 days, all aircraft)

Aircraft and Owner/Operator Information

Aircraft Make: BELL
Registration: N9526
Model/Series: 47G 2A
Aircraft Category: Helicopter
Year of Manufacture: 1954
Amateur Built: No
Airworthiness Certificate: Restricted
Serial Number: 1288-16
Landing Gear Type: Skid;
Seats: 3
Date/Type of Last Inspection: 06/29/2017, Annual
Certified Max Gross Wt.: 2850 lbs
Time Since Last Inspection: 10 Hours
Engines: 1 Reciprocating
Airframe Total Time:  13300 Hours as of last inspection
Engine Manufacturer: LYCOMING
ELT: Not installed
Engine Model/Series: VO-435-A1D
Registered Owner: On file
Rated Power: 240 hp
Operator: On file
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: FIG, 1516 ft msl
Distance from Accident Site: 22 Nautical Miles
Observation Time: 1154 EDT
Direction from Accident Site: 180°
Lowest Cloud Condition: Clear
Visibility:  10 Miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 5 knots /
Turbulence Type Forecast/Actual: /
Wind Direction: 200°
Turbulence Severity Forecast/Actual: /
Altimeter Setting: 30.2 inches Hg
Temperature/Dew Point: 22°C / 17°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: St Marys, PA (OYM)
Type of Flight Plan Filed: None
Destination: St Marys, PA (OYM)
Type of Clearance: None
Departure Time: 1000 EDT
Type of Airspace: Class G

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 None
Latitude, Longitude: 41.407778, -78.561667 (est)

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