# Incident 20240726011829I: Bell 407, Council Hill, OK, July 26, 2024

- Type: FAA incident report (Accident/Incident Data System), as reported
- Date: July 26, 2024, 23:30 local time
- Place: Council Hill, OK
- Damage: Minor damage
- Phase of flight: Cruise/Level Flight
- Operating rules: Air taxi and commuter (Part 135)
- Operator: 2VKA
- Location: 35.5808° N, 95.6075° W: From the FAA
- Nearby events: https://openairdocs.org/map.md?lat=35.5808&lon=-95.6075&mi=10
- Aircraft: N793SF, registered now (https://openairdocs.org/aircraft/N793SF) (OpenAirDocs)
- Registry model: Bell 407 (registry code 1182206, https://openairdocs.org/model/bell-407) (OpenAirDocs)
- Registry engine: Rolls-Royce 250-C47B (registry code 54585, https://openairdocs.org/engine/rolls-royce-250-c47b) (OpenAirDocs)
- Reported make and model: BELL 407
- Reported engine: ROLLS-ROYC 250
- People aboard: 3
- Fatal injuries: 0
- Other injuries: 0
- Pilot certificates: Commercial pilot
- Pilot flight hours: 3,152 total
- NTSB investigation: [NTSB ENG24LA028](https://openairdocs.org/ntsb/ENG24LA028) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/20240726011829I

## Narrative

As the FAA filed it, in capitals; the FAA replaces private details with ^PRIVACY DATA OMITTED^.

THE BELL 407 HELICOPTER WAS EN ROUTE, RETURNING TO THE BASE LOCATION AFTER A PATIENT TRANSFER. DURING CRUISE FLIGHT AT 1900 FEET AT NIGHT UNDER NIGHT VISION GOGGLES, THE AIRCRAFT EXPERIENCED A CATASTROPHIC ENGINE FAILURE. THE FLIGHT CREW REPORTED THEY SAW AN INSTANTANEOUS BRIGHT FLASH TO THE AIRCRAFT'S REAR, A LOUD BANG, FOLLOWED BY THE HELICOPTER YAWING TO THE LEFT. THE PIC INITIATED AN AUTOROTATION. TOWARDS THE END OF THE AUTOROTATION DESCENT, THE PIC INITIATED A FLARE; HOWEVER, DURING THE FLARE, POWERLINES WERE SEEN PERPENDICULAR TO THE AIRCRAFT'S FLIGHT PATH. PIC DECREASED COLLECTIVE PITCH TO NEAR ZERO TO GET AIRCRAFT ON THE GROUND QUICKLY BEFORE POWERLINES. PIC ACTIONS CAUSED THE AIRCRAFT TO EXPERIENCE A “HARD LANDING,” RESULTING IN THE MAIN ROTOR BLADES CONTACTING THE FINLETS ON THE HORIZONTAL STABILIZER. ALL THREE CREW MEMBERS DID NOT SUSTAIN ANY INJURIES. LATER, THE CREW REPORTED THAT NO ANOMALIES HAD BEEN OBSERVED BEFORE THE ENGINE FAILURE.

THE AIRCRAFT ENGINE WAS REMOVED AND SENT TO THE ENGINE MANUFACTURER FOR A TEARDOWN EXAMINATION. NO ISSUES WERE FOUND DURING THE INITIAL EXAM. THE ENGINE'S INTERNAL COMPONENTS WERE SENT TO THE METALLURGY LABORATORY FOR FURTHER EXAMINATION.

## The NTSB's investigation of this event (1)

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.

- [NTSB ENG24LA028](https://openairdocs.org/ntsb/ENG24LA028), Jul 26, 2024: Bell 407 (N793SF), Oktaha, OK, incident, minor damage. Probable cause: The loss of engine power due to high cycle fatigue failure of a power turbine stage 3 turbine wheel blade. The resulting engine imbalance caused a decoupling of the gas producer stage 1 and stage 2…

From the FAA Accident/Incident Data System. Reports are matched to registry aircraft by N-number and event date, checked against the reported make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. For accidents, the NTSB's own investigation is the fuller record.

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