# NTSB LAX90LA164: Bell 47G, N9FK, Riverside, CA, May 4, 1990

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: May 4, 1990, 10:30 local (17:30 UTC)
- Place: Riverside, CA
- Coordinates: 33.899803, -117.399765 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.8998&lon=-117.3998&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report September 5, 1991
- Report: Approved by Office Director
- NTSB case key (mKey): 26794
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX90LA164
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/26794/pdf
- Page: https://openairdocs.org/ntsb/LAX90LA164

## Probable cause

THE PILOT'S FAILURE TO MAINTAIN CONTROL OF THE HELICOPTER. A FACTOR RELATED TO THE ACCIDENT WAS: THE PILOT'S LACK OF EXPERIENCE IN THE TYPE OF AIRCRAFT.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Roll over, hover
  - aircraft control - not maintained, pilot in command (cause)
  - lack of total experience in type of aircraft, pilot in command (contributing factor)

## Analysis

THE PILOT, WHO HAD A SINGLE ENGINE LAND RATING, WAS TAKING INSTRUCTION IN ROTORCRAFT. WHILE IN A HOVER, THE HELICOPTER BEGAN DRIFTING TO THE RIGHT REAR, THEN ROLLED OVER.

## Aircraft

- Registration: [N9FK](https://openairdocs.org/deregistered/N9FK-2017-04-18), registration cancelled 2017-04-18, S/N 1675, built 1956 (OpenAirDocs)
- Reported make and model: BELL 47G
- Registry model: [Bell 47G](https://openairdocs.org/model/bell-47g) (registry code 1181002) (OpenAirDocs)
- Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1675
- Engines: LYCOMING VO-435 260 horsepower reciprocating
- Damage: Substantial damage
- Fire: On-Ground
- Flight: Instructional, Part 91
- Operator: Riverside Air Service
- Departed: RAL
- Airport: RAL, Riverside Muni

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 43; private; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; flight hours: 225 total, 5 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F

## 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 19900504014009A](https://openairdocs.org/incident/19900504014009A), May 4, 1990: Bell 47G, Riverside, CA, Substantial damage. Student experienced dynamic rollover during low level hover practice. Apparently a skid touched during hover.

## Other investigations on N9FK (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 WPR11LA190](https://openairdocs.org/ntsb/WPR11LA190), Apr 6, 2011: Bell 47G (N9FK), Torrance, CA, substantial damage. Probable cause: The pilot did not maintain adequate altitude during takeoff, which resulted in ground contact and a dynamic rollover.

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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