# Accident 20040403004479A: Bell 47G4A, Shafter, CA, April 3, 2004

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: April 3, 2004, 08:58 local time
- Place: Shafter, CA
- Damage: Substantial damage
- Phase of flight: Maneuver
- Operating rules: Agricultural (Part 137)
- Operator: PWWG
- Location: 35.3500° N, 119.0000° W: From the FAA
- Nearby events: https://openairdocs.org/map.md?lat=35.3500&lon=-119.0000&mi=10
- Aircraft: N7NB, registered now (https://openairdocs.org/aircraft/N7NB) (OpenAirDocs)
- Registry model: Bell 47G-4A (registry code 1181031, https://openairdocs.org/model/bell-47g-4a) (OpenAirDocs)
- Registry engine: Lycoming VO-540 series (registry code 41534, https://openairdocs.org/engine/lycoming-vo-540-series) (OpenAirDocs)
- Reported make and model: BELL 47G4A
- Fatal injuries: 0
- Pilot flight hours: 0 total, 0 in this make and model, 0 in the last 90 days
- NTSB investigation: [NTSB LAX04LA176](https://openairdocs.org/ntsb/LAX04LA176) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/20040403004479A

## Narrative

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

(-23) DURING AERIAL APPLICATION, THE ROTORCRAFT EXPERIENCED LOSS OF TAIL ROTOR AUTHORITY. FURTHER INVESTIGATION REVEALED THAT ALL HANGAR BEARINGS, SPLINE-COUPLING SHAFTS AND GEARING (OUTPUT QUILL) FROM THE TRANSMISSION TO THE TAIL ROTOR GEARBOX APPEARED TO BE WITHOUT DAMAGE OR ANY OVERHEATING CONDITION. THERE WAS A CRACK ON THE TAIL BOOM FRAME THAT WAS CONSIDERED SUSPECT TO THE ACCIDENT. THIS SMALL SEGMENT OF THE TAIL BOOM FRAME WAS REMOVED FOR FURTHER VISUAL ANALYSIS, WHICH CONFIRMED A DARK OUTLINE OF RUST INDICATING A LONG TIME CRACK. ADDITIONALLY, IT WAS NOTED THAT THE CROSS-OVER SUPPORT TUBE WAS MISSING IN THAT PORTION OF THE TAIL BOOM FRAME. THIS WOULD EXPLAIN THE CRACK THAT GENERATED ON THIS PORTION OF THE FRAME DUE TO THE EXCESSIVE TORQUE BEING APPLIED DURING PEDAL TURNS.

## 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 LAX04LA176](https://openairdocs.org/ntsb/LAX04LA176), Apr 3, 2004: Bell 47G-4A (N7NB), Bakersfield, CA, substantial damage. Probable cause: a loss of tail rotor drive due to a disconnection of the drive shaft's splined coupling at the tail rotor gear box. The splined coupling to tail rotor gear box disconnection occurred as a result of…

## Other reports on N7NB (1)

Matched to the same aircraft by N-number and date.

- [Accident 19811016068109A](https://openairdocs.org/incident/19811016068109A), Oct 16, 1981: Bell 47G4A (N7NB), Wasco, CA, Substantial damage. Helicopter crashed during emergency landing after engine failure.

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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