# NTSB CEN11LA499: Air Tractor AT-502, N1516G, Fergus Falls, MN, July 22, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 21, 2011, 19:26 local (Jul 22, 2011, 00:26 UTC) - Place: Fergus Falls, MN - Coordinates: 46.279781, -96.060203 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=46.2798&lon=-96.0602&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report November 7, 2012 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 81194 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN11LA499 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/81194/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=81194 - Page: https://openairdocs.org/ntsb/CEN11LA499 ## Probable cause The total loss of engine power for reasons that could not be determined because the airplane came to rest inverted in water. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Air Tractor AT-502, 4 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=0390303), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Air Tractor AT-502, 4 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=0390303), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Air Tractor AT-502, 7 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=0390303), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-flare/touchdown: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Air Tractor AT-502, 17 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=0390303), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot stated that, while returning to the airport at the end of a 1-hour aerial application flight, the airplane experienced a gradual loss of engine power. The engine then lost all power, and the pilot performed a forced landing to a field immersed in water. The airplane nosed over during the landing, and the airframe and engine were immersed in the water. The pilot stated that the airplane had been fueled from a 300 gallon tank used to shuttle fuel. Examination of the wreckage, which took place 12 days after the accident, revealed no fuel within the examined portions of the fuel system, and water contamination within the fuel control unit and fuel pump. Determination of whether the lack of fuel noted was due to the airplane's inverted position and the time of the examination or whether the contamination was due to the water immersion could not be made. ## Factual narrative On July 21, 2011, about 1926 central daylight time, an Air Tractor Inc AT-502, N1516G, experienced a total loss of engine power following the completion of an aerial application of a field near Fergus Falls, Minnesota. The pilot subsequently made a forced landing to a field along a highway. The certificated commercial pilot was uninjured. The airplane sustained substantial damage to the fuselage and wings. The airplane was registered to and operated by Farmers Union Oil Co. (DBA Cenex Airspray) under the provisions of 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual meteorological conditions prevailed at the time of the accident. The flight originated from Fergus Falls Municipal Airport-Einar Mickelson Field (FFM), Fergus Falls, Minnesota, about 1810. The pilot stated that the airplane was fueled from a 300 gallon tank used to shuttle fuel. The pilot stated that there was 120 gallons of fuel aboard the airplane at the time of takeoff, and the fuel gauges indicated that the fuel tanks were 1/3 full. The pilot stated that the fuel consumption rate was approximately 50 gallons per hour. The pilot stated that he departed FFM and performed two aerial applications on two different fields before returning to FFM. He stated that his cruise altitude was 600 feet above ground level for the return. About 4-5 miles south of FFM, the airplane started losing engine power. He turned on the fuel boost pump and igniters to continuous operation. About 1 mile south of the FFM, the airplane experienced a total loss of engine power. The pilot then attempted a forced landing to a highway but had to abort the landing because of a vehicle that was turning onto the highway. The pilot landed into an area of 2 foot deep water located on the east side of the highway due to a powerline on the west side of the highway. The airplane nosed over during the landing. The airplane remained inverted until it was examined at FFM. The airplane was examined by a Federal Aviation Administration airworthiness inspector from the Minneapolis Flight Standards District Office on August 2, 2011, at FFM. Prior to the airplane being placed in an upright position, the inspector removed the drain plugs from the firewall fuel filter. The main fuel supply line to the engine produced no fuel. Removal of the fuel line through the fuel/oil heat exchanger produced less than 1/2 ounce of fuel. When the engine was removed from the firewall, there was a mixture of water with some oil that drained out of the hot section, but there was no fuel. The airplane was then uprighted and water drained out of the fuselage section. The operator had a repair station examine the fuel control unit (FCU) and the fuel pump. The FCU exhibited corrosion damage on the drive section, main housing, and water beads were noted in the bellows (air) chamber. The fuel pump exhibited water contamination in the fuel bowl and drive spline. ## Aircraft - Registration: [N1516G](https://openairdocs.org/deregistered/N1516G-2019-08-13), registration cancelled 2019-08-13, S/N 502-0153 (OpenAirDocs) - Reported make and model: Air Tractor Inc AT-502 - Registry model: [Air Tractor AT-502](https://openairdocs.org/model/air-tractor-at-502) (registry code 0390303) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Airplane - Serial number: 502-0153 - Airframe hours: 7559.6 - Engines: Pratt and Whitney PT6A-15AG 680 horsepower turbo prop - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Farmers Union Oil Company, doing business as Cenx Airspray - Registered owner: Farmers Union Oil Company - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, July 15, 2011 - Departed: FFM, Fergus Falls, MN - Destination: FFM, Fergus Falls, MN - Airport: FFM, Fergus Falls Municipal Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 45; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, with waivers/limitations; last flight review December 4, 2010; seat: single; flight hours: 10,970 total, 4,000 in this make and model, 10,970 as pilot in command, 212 in the last 90 days, 140 in the last 30 days, 8 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 220° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 77 °F, dew point 57 °F - Altimeter: 29.79 inHg - Observed at: FFM, 2 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20110721015299A](https://openairdocs.org/incident/20110721015299A), Jul 21, 2011: Air Tractor Inc AT-502, Fergus Falls, MN, Substantial damage. Pilot stated that he lost partial power along with drop in fuel presure. Turned on fuel pump with no result. Was 3-4 mile from ffm airport at 700-800 feet.… ## Docket (3 files) The files NTSB released with the investigation on August 13, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=81194. 1.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 684 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40373063&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Examination - FAA (item 2, .PDF, 52 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40373058&FileExtension=.PDF&FileName=Record%20of%20Examination%20-%20FAA-Master.PDF - Record of Component Examination (item 3, .PDF, 729 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40373064&FileExtension=.PDF&FileName=Record%20of%20Component%20Examination-Redacted.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.