# Accident 19981211033299A: Bell 47G2, Helendale, CA, December 11, 1998

- Type: FAA accident report (Accident/Incident Data System), as reported
- Date: December 11, 1998, 16:45 local time
- Place: Helendale, CA
- Damage: Substantial damage
- Phase of flight: Fcd/Prec Ldg From Cruise
- Operating rules: General operating rules (Part 91)
- Location: 34.7393° N, 117.3493° W: From the FAA, an estimate near the named town, within about 3 miles
- Nearby events: https://openairdocs.org/map.md?lat=34.7393&lon=-117.3493&mi=10
- Aircraft: N9021R, registered now (https://openairdocs.org/aircraft/N9021R) (OpenAirDocs)
- Registry model: Bell-Continental Copters 47G2 (registry code 1181069, https://openairdocs.org/model/bell-continental-copters-47g2) (OpenAirDocs)
- Registry engine: Lycoming VO-435-A1F (registry code 42200, https://openairdocs.org/engine/lycoming-vo-435-a1f) (OpenAirDocs)
- Reported make and model: BELL 47G2
- Reported engine: LYC VO435A1B
- People aboard: 1
- Fatal injuries: 0
- Pilot certificates: Student
- Pilot flight hours: 800 total, 148 in this make and model
- NTSB investigation: [NTSB LAX99LA047](https://openairdocs.org/ntsb/LAX99LA047) (OpenAirDocs)
- FAA source: FAA Aviation Safety Information Portal (https://asip.faa.gov/)
- Page: https://openairdocs.org/incident/19981211033299A

## Narrative

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

(.19)ON DECEMBER 11, 1998, AT 1645 HOURS PACIFIC STANDARD TIME, A BELL 47G2, N9021R, SUSTAINED SUBSTANTIAL DAMAGE DURING A FORCED LANDING NEAR HELENDALE, CALIFORNIA, FOLLOWING THE ONSET OF AN AIRFRAME VIBRATION. THE STUDENT PILOT, THE SOLE OCCUPANT, WAS NOT INJURED.  THE PERSONAL FLIGHT ORIGINATED AT CRAMERS JUNCTION, CALIFORNIA, AT 1630, AND WAS EN ROUTE TO HELENDALE.  VISUAL METEOROLOGICAL CONDITIONS PREVAILED AND NO FLIGHT PLAN WAS FILED.  THE PILOT REPORTED THAT HE WAS FLYING AT 200 FEET AGL WHEN HE FELT THE HELICOPTER BEGIN TO SHAKE.  AS HE REDUCED THE POWER, THE HELICOPTER STOPPED SHAKING.  THE PILOT AUTOROTATED AND LANDED IN AN AREA OF HILLY AND UNEVEN TERRAIN.  THE TAIL ROTOR BLADES IMPACTED AN EMBANKMENT AND THE MAIN ROTOR BLADES SEVERED THE TAILBOOM. (.4) THE PILOT ENCOUNTERED RETREATING BLADE STALL WHILE FLYING AT 100 MPH.  HE REPORTED THAT THE HELICOPTER BEGAN TO SHAKE AND IT FELT LIKE AN 'OUT OF BALANCE FEELING, LIKE WHEN THE WASHING MACHINE GETS UNBALANCED.'  THE ROTOR RPM BEGAN TO DECAY.  WHEN HE REDUCED POWER AND STABILIZED THE AIRSPEED ABOUT 60 TO 65 MPH, THE SHAKING STOPPED.  THE PILOT STATED THAT HE WAS NOT ABLE TO MAINTAIN LIFT, SO HE ENTERED AN AUTOROTATION OV ER THE HILLY TERRAIN. THE TAIL ROTOR BLADES IMPACTED AN EMBANKMENT AND THE MAIN ROTOR BLADES SEVERED THE TAIL BOOM.  THE PILOT'S MANUAL FOR THE BELL 47G2 INDICATES THAT THE 'NEVER-EXCEED SPEED' (VNE) FOR THE HELICOPTER IS 100 MPH.  ACCORDING TO THE FAA'S BASIC HELICOPTER HANDBOOK, THE RECOVERY PROCEDURE FOR RETREATING BLADE STALL IS TO REDUCE THE COLLECTIVE PITCH, INCREASE ROTOR RPM, REDUCE FORWARD AIRSPEED, AND MINIMIZE MANEUVERING.

## 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 LAX99LA047](https://openairdocs.org/ntsb/LAX99LA047), Dec 12, 1998: Bell 47G2 (N9021R), Helendale, CA, substantial damage. Probable cause: The pilot's failure to follow proper procedures to recover from main rotor blade aerodynamic retreating blade stall.

## Other reports on N9021R (3)

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

- [Accident 20120101000549A](https://openairdocs.org/incident/20120101000549A), Jan 1, 2012: Bell-Continental Copters Inc. 47G2 (N9021R), Lohn, TX, Substantial damage. Pilot stated he did a pre flight inspection per the operator's manual, loaded his passenger for the purpose of pasture count of deer on hunting leases. On the…
- [Accident 19970812021809A](https://openairdocs.org/incident/19970812021809A), Aug 12, 1997: Bell 47G2 (N9021R), Mojave, CA, Substantial damage. On August 12, 1997, at 1000 pacific daylight time, a Bell 47G2, N9021R, la ned hard on runway 4 at the Mojave, California airport. The local area instructional…
- [Incident 19830206007729I](https://openairdocs.org/incident/19830206007729I), Feb 6, 1983: Bell 47G2 (N9021R), Corona, CA, Minor damage. Pilot had yaw problems during hovering. Found tail rotor drive shaft failed.

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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