# NTSB FTW90GA146: Robinson R22B, N20K, Tahlequah, OK, July 26, 1990

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: July 26, 1990, 13:58 local (18:58 UTC)
- Place: Tahlequah, OK
- Coordinates: 35.909416, -94.970397 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.9094&lon=-94.9704&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report December 30, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 23049
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW90GA146
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/23049/pdf
- Page: https://openairdocs.org/ntsb/FTW90GA146

## Probable cause

THE PILOT'S FAILURE TO MAINTAIN ADEQUATE ALTITUDE.

## Sequence of events

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

- In flight collision with object, cruise
  - object - wire,static (contributing factor)
  - altitude - inadequate, pilot in command (cause)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE PUBLIC USE HELICOPTER WAS IN LOW LEVEL CRUISE FLIGHT WEST BOUND ALONG A HIGHWAY WHEN IT STRUCK AN UNMARKED STATIC LINE. IT DESCENDED UNCONTROLLED AND IMPACTED THE HIGHWAY. THE AREA SURROUNDING THE FIVE WIRE HIGH TENSION POWERLINES WAS HILLY AND COVERED WITH DENSE FOLIAGE. EXAMINATION OF THE WRECKAGE REVEALED NO STRUCTURAL OR MECHANCIAL ANOMALIES. THE POWERLINES WERE DEPICTED ON THE SECTIONAL AERONANTICAL CHART.

## Aircraft

- Registration: [N20K](https://openairdocs.org/deregistered/N20K-1990-10-01), registration cancelled 1990-10-01, S/N 789 (OpenAirDocs)
- Reported make and model: Robinson R22B
- Registry model: [Robinson Helicopter R22 BETA](https://openairdocs.org/model/robinson-helicopter-r22-beta) (registry code 7640110) (OpenAirDocs)
- Category: Helicopter
- Serial number: 789
- Airframe hours: 1438
- Engines: LYCOMING O-320-B2C 160 horsepower reciprocating
- Damage: Destroyed
- Flight: Public aircraft, Public use
- Operator: State Of Oklahoma, doing business as Oklahoma Highway Patrol
- Last inspection: 100 hour, July 6, 1990, 40 hours before
- Departed: HAX, MUSKOGEE, OK
- Destination: NONE, ADAIR CTY., OK

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 39; private; airplane ratings: single-engine land; medical: class 2, valid medical--no waivers/lim.; seat: right; toxicology performed; flight hours: 1,127 total, 924 in this make and model, 1,006 as pilot in command, 94 in the last 90 days, 32 in the last 30 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 180° at 15 knots
- Visibility: 12 statute miles
- Lowest ceiling: 12,000 ft overcast
- Temperature: 90 °F, dew point 66 °F
- Altimeter: 30.00 inHg
- Observed at: TUL, 25 nm away

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.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.