# NTSB FTW91LA007: Bell 47G, N1071Z, Grand Prairie, TX, October 20, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: October 20, 1990, 17:05 local (22:05 UTC)
- Place: Grand Prairie, TX
- Coordinates: 32.729309, -97.000564 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=32.7293&lon=-97.0006&mi=10
- Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report December 30, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 23285
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW91LA007
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/23285/pdf
- Page: https://openairdocs.org/ntsb/FTW91LA007

## Probable cause

THE PILOT'S INADEQUATE COMPENSATION FOR THE EXISTING TAILWIND CONDITIONS AND HIS FAILURE TO MAINTAIN ROTOR RPM.

## Sequence of events

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

- Loss of control - on ground/water, taxi - aerial
  - weather condition - tailwind
  - compensation for wind conditions - inadequate, pilot in command(cfi) (cause)
  - rotor rpm - not maintained, pilot in command(cfi) (cause)
- Roll over, landing - flare/touchdown
  - terrain condition - downhill (contributing factor)

## Analysis

THE CFI WAS HOVER TAXIING IN AN APPROXIMATE 20 KT TAILWIND CONDITION. HE NOTICED A DECREASE IN ROTOR RPM AND, ACCORDING TO HIS WRITTEN REPORT, 'REAPPLIED POWER TO REGAIN RPMS.' THE PILOT ELECTED TO LAND INTO THE WIND. TOUCHDOWN OCCURRED ON A SLOPE AND THE HELICOPTER ROLLED ONTO ITS RIGHT SIDE.

## Aircraft

- Registration: [N1071Z](https://openairdocs.org/deregistered/N1071Z-2002-08-08), registration cancelled 2002-08-08, S/N 999, built 1961 (OpenAirDocs)
- Reported make and model: BELL 47G
- Registry model: [Bell 47G](https://openairdocs.org/model/bell-47g) (registry code 1181002) (OpenAirDocs)
- Registry engine: [Franklin 6VS-335 series](https://openairdocs.org/engine/franklin-6vs-335-series) (registry code 27040, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 999
- Engines: LYCOMING reciprocating
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: Gary Mcfall, doing business as Action Helicopter
- Departed: F67
- Destination: F67
- Airport: F67, Grand Prairie

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 51; flight instructor, commercial; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; flight hours: 8,000 total, 4,000 in this make and model, 100 in the last 90 days, 30 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 190° at 20 knots, gusting 35
- Lowest ceiling: none
- Temperature: 73 °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 19901020046509A](https://openairdocs.org/incident/19901020046509A), Oct 20, 1990: Bell 47G, Grand Prairie, TX, Substantial damage. While hover taxiing in gusty surface wind rotor speed decayed. Elected to land on uneven ground. Rolled over.

## Other investigations on N1071Z (2)

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 SEA73DYA05](https://openairdocs.org/ntsb/SEA73DYA05), Aug 6, 1972: Bell 47G (N1071Z), Murtaugh, ID, substantial damage
- [NTSB LAX66A0027](https://openairdocs.org/ntsb/LAX66A0027), Sep 15, 1965: Bell 47G (N1071Z), Las Vegas, NV, destroyed

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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