# NTSB CEN20LA279: Air Tractor AT502, N61315, Dalhart, TX, July 10, 2020

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 3 · Limited · Final report
- Date: July 10, 2020, 14:55 local (19:55 UTC)
- Place: Dalhart, TX
- Coordinates: 36.060832, -102.518608 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=36.0608&lon=-102.5186&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: Approved by Office Director
- Investigation class: Class 3
- NTSB office: Central Region
- Parties: FAA Flight Standards, Honeywell Aerospace, Pratt & Whitney Canada
- NTSB case key (mKey): 101592
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN20LA279
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/101592/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=101592
- Page: https://openairdocs.org/ntsb/CEN20LA279

## Probable cause

The total loss of engine power due to a failed fuel control unit bearing.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Engine fuel and control: fuel control/carburetor](https://openairdocs.org/ntsb-findings/01057322): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Air Tractor AT-502B, 1 case](https://openairdocs.org/ntsb-findings/01057322/cases.md?model=0390307), [All aircraft, 195 cases](https://openairdocs.org/ntsb-findings/01057322/cases.md)
- [Terrain: rough terrain](https://openairdocs.org/ntsb-findings/03021015): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Air Tractor AT-502B, 3 cases](https://openairdocs.org/ntsb-findings/03021015/cases.md?model=0390307), [All aircraft, 442 cases](https://openairdocs.org/ntsb-findings/03021015/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Enroute-cruise: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340); cases with it: [Air Tractor AT-502B, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=0390307), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md)
- [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Air Tractor AT-502B, 8 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=0390307), [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-502B, 14 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=0390307), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)

## Analysis

The operator reported that the pilot was returning to the airport after completing an aerial application when the engine lost power. The pilot executed a forced landing to a pasture. An engine examination revealed that the fuel control unit (FCU) input drive shaft would not rotate. Further examination established that the FCU input drive spool bearing had failed; however, the cause of the bearing failure could not be determined. Maintenance records indicated that the FCU was within the inspection and overhaul requirements recommended by the manufacturer.

## Factual narrative

On July 10, 2020, about 1455 central daylight time, an Air Tractor AT-502B airplane, N61315, was substantially damaged when it was involved in an accident near Dalhart, Texas. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 137 flight. The operator reported that the pilot was returning to the airport after completing an aerial application when the engine lost power. The pilot executed a forced landing to a pasture. Both wings sustained substantial damage during the landing. An engine examination revealed that the fuel control unit (FCU) input drive shaft would not rotate. Further examination established that the FCU input drive spool bearing had failed; however, the cause of the bearing failure could not be determined. The FCU was overhauled in July 2016. The overhaul facility reported that the spool bearing was replaced at that time. The airplane maintenance records do not include a notation as to when the FCU was installed on the engine. As a result, the exact time in service was not determined. However, the engine accumulated about 594 hours since December 2016. The FCU manufacturer recommended an inspection every 3,000 hours and an overhaul every 6,000 hours time-in-service. Both the spool and drive bearings are required to be replaced at those intervals.

## Aircraft

- Registration: [N61315](https://openairdocs.org/aircraft/N61315), registered now, S/N 502B-0305, built 1995 (OpenAirDocs)
- Reported make and model: Air Tractor AT502 (B)
- Registry model: [Air Tractor AT-502B](https://openairdocs.org/model/air-tractor-at-502b) (registry code 0390307) (OpenAirDocs)
- Registry engine: [Pratt & Whitney PT6A series](https://openairdocs.org/engine/pratt-whitney-pt6a-series) (registry code 52034, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 502B-0305
- Year built: 1995
- Airframe hours: 7904.4
- Engines: Pratt & Whitney PT6A-34 750 horsepower turbo prop
- Damage: Substantial damage
- Flight: Aerial observation, Part 137
- Operator: Bailey Flying Service Inc.
- Registered owner: Lease Air Inc.
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, May 23, 2020, 27.3 hours before
- Departed: DHT, Dalhart, TX
- Destination: DHT, Dalhart, TX

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review February 28, 2019; seat: single; restraint: 4-point; flight hours: 5,399 total

## Weather

- Conditions: Visual (VMC), Day
- Wind: 40° at 12 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 90 °F, dew point 66 °F
- Altimeter: 30.12 inHg
- Observed at: DHT, 20 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 20200710016559A](https://openairdocs.org/incident/20200710016559A), Jul 10, 2020: Air Tractor Inc AT-502B, Dalhart, TX, Substantial damage. Dalhart, TX: N61315, AT-502B, aircraft finished aerial application and was returning to base, when engine surged and propeller feathered. Pilot made a forced…

## Docket (7 files)

The files NTSB released with the investigation on February 24, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=101592. 156 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 10.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12006279&FileExtension=pdf&FileName=Operator%20Accident%20Rpt%20--%20CEN20LA279_redacted-Rel.pdf
- Accident photos (item 2, PDF, 5 pages, 1.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12044852&FileExtension=pdf&FileName=Accident%20Photos%20--%20CEN20LA279-Rel.pdf
- Examination summary -- fuel control unit (item 3, PDF, 4 pages, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12053333&FileExtension=pdf&FileName=Examination%20Summary%20--%20CEN20LA279-Rel.pdf
- Maintenance records -- airframe (excerpt) (item 4, PDF, 5 pages, 30.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12006570&FileExtension=pdf&FileName=Airframe%20Log%20~%20N61315%20(Excerpt)_redacted-Rel.pdf
- Maintenance records -- engine (item 5, PDF, 14 pages, 112 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12007001&FileExtension=pdf&FileName=Engine%20Log%20~%20N61315_redacted-Rel.pdf
- Overhaul work order inspection report -- fuel control unit (item 6, PDF, 2 pages, 98 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12007484&FileExtension=pdf&FileName=FCU%20Overhaul%20Inspection%20Report%20--%20Kansas%20Aviation-Rel.pdf
- Statement of party representatives to NTSB investigation (item 7, PDF, 1 page, 150 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12006761&FileExtension=pdf&FileName=Party%20Stmt%20--%20Honeywell_redacted-Rel.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.

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