# NTSB FTW92LA040: Bell 206L-3+, N2770X, Arlington, TX, December 10, 1991

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: December 10, 1991, 08:55 local (14:55 UTC)
- Place: Arlington, TX
- Coordinates: 32.749752, -97.079429 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=32.7498&lon=-97.0794&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report June 30, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 18420
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW92LA040
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18420/pdf
- Page: https://openairdocs.org/ntsb/FTW92LA040

## Probable cause

THE HELICOPTER'S AUTOROTATIONAL LANDING PERFORMANCE CAPABILITY WAS EXCEEDED. FACTORS WERE THE PROPER DESCENT RATE WAS NOT POSSIBLE FOR THE PIC AND SUFFICIENT INFORMATION FROM THE MANUFACTURER WAS NOT PROVIDED.

## Sequence of events

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

- Hard landing, landing - flare/touchdown
  - emergency procedure - simulated, pilot in command
  - autorotation - performed, pilot in command
  - aircraft performance,landing capability - exceeded (cause)
  - proper descent rate - not possible, pilot in command (contributing factor)
  - information insufficient, manufacturer (contributing factor)
  - misc rotorcraft,tail boom - buckled
  - rotor drive system,tail rotor drive shaft - separation

## Analysis

THE EXPERIMENTAL CERTIFICATED HELICOPTER WAS BEING TEST FLOWN AS PART OF THE HEIGHT VELOCITY DIAGRAM DEVELOPMENT FOR THE 206L4 CERTIFICATION PROGRAM. THE TEST PILOT WAS CONDUCTING ABORTED TAKEOFFS WHEN AT 30 FEET AND 50 KNOTS HE INITIATED AN AUTOROTATION. THE COLLECTIVE WAS LOWERED SLIGHTLY AND A HIGH DESCENT RATE OCCURRED. DURING THE DESCENT THE MAIN ROTOR RPM DECREASED AND THE HELICOPTER LANDED HARD RESULTING IN TAILBOOM BUCKLING AND SEPARATION OF THE TAIL ROTOR DRIVE SHAFT. THE PILOT'S APPLICATION OF COLLECTIVE BEFORE TOUCHDOWN DID NOT ARREST THE DESCENT RATE.

## Aircraft

- Registration: N2770X (not matched to a registry record)
- Reported make and model: BELL 206L-3+
- Category: Helicopter
- Serial number: 51022
- Airframe hours: 3577
- Engines: ALLISON 250C-30P 650 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 91
- Operator: Bell Helicopter Textron
- Registered owner: Bell Helicopter Textron
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: 100 hour, August 14, 1991, 53 hours before
- Airport: F54, Arlington Municipal, runway 16, 4,000 × 100 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 53; commercial, flight instructor; airplane ratings: single-engine land; instrument ratings: helicopter, airplane; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 8,200 total, 100 in this make and model, 8,000 as pilot in command, 50 in the last 90 days, 20 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 12 statute miles
- Lowest ceiling: none
- Temperature: 52 °F, dew point 46 °F
- Altimeter: 30.00 inHg
- Observed at: DFW, 10 nm away

## 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 19911210063059A](https://openairdocs.org/incident/19911210063059A), Dec 10, 1991: Bell STC206BELL, Arlington, TX, Substantial damage. Cut power on initial takeoff per test flight program. Too slow and low for full collective. Impact bent tailboom.

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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