# NTSB DEN85FTM04: Kokes Scorpion 133, N45877, Grand Junction, CO, June 29, 1985

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Final report
- Date: June 29, 1985, 12:49 local (18:49 UTC)
- Place: Grand Junction, CO
- Coordinates: 39.10958, -108.530517 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.1096&lon=-108.5305&mi=10
- Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 16576
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN85FTM04
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16576/pdf
- Page: https://openairdocs.org/ntsb/DEN85FTM04

## Sequence of events

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

- Miscellaneous/other, taxi - aerial
  - visual lookout - inadequate, pilot in command (contributing factor)
  - object - aircraft moving on ground
  - maneuver - performed, pilot in command
- Roll over, taxi - aerial
  - aircraft handling - not maintained, pilot in command (cause)
  - lack of recent experience in type of aircraft, pilot in command (contributing factor)

## Analysis

A GROUP OF PLTS WERE PREPARING FOR AN AIRSHOW FLYBY. AS A FORMATION OF AIRPLANES WERE BEING TAXIED TO RWY 29, THE PLT OF A HOME BUILT SCORPION 133 HELICOPTER, N45877, WAS CLEARED TO AIR TAXI ACROSS RWY 29 & PROCEED TO RWY 22. AS THE HELICOPTER PLT WAS APPROACHING RWY 22 & WAS IN A DESCENDING LEFT TURN, A HOME BUILT AIRPLANE WAS TAKING OFF ON THE SAME RWY (22). TO AVOID A POSSIBLE COLLISION, THE HELICOPTER PLT MADE A HARD LEFT TURN & 'PUSHED IT TO THE GROUND' BETWEEN RWY 22 & THE PARALLEL TAXIWAY. DURING TOUCHDOWN, THE HELICOPTER ROLLED OVER. THE PLT STATED THAT THE LANDING WAS NOT HARD. HE BELIEVED THAT GYROSCOPIC PRECESSION CAUSED THE HELICOPTER TO ROLL OVER.

## Aircraft

- Registration: N45877 (not matched to a registry record)
- Reported make and model: KOKES SCORPION 133 (SCORPION 1)
- Category: Helicopter, amateur-built
- Serial number: 12598
- Airframe hours: 1756
- Engines: Rotorway RW133 160 horsepower reciprocating
- Damage: Substantial damage
- Flight: Part 91
- Registered owner: Robert L. Kokes
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, January 19, 1985, 94 hours before
- Departed: GJT
- Destination: GJT
- Airport: GJT, Walker Field, runway 22, 5,366 × 100 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 47; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 478 total, 170 in this make and model, 426 as pilot in command, 7 in the last 90 days, 7 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 290° at 6 knots, gusting 10
- Visibility: 90 statute miles
- Lowest ceiling: 25,000 ft broken
- Temperature: 82 °F, dew point 39 °F
- Altimeter: 30.00 inHg
- Observed at: GJT

## 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 19850629031889A](https://openairdocs.org/incident/19850629031889A), Jun 29, 1985: Amtrrw SCORPION1, Grand Junction, CO, Substantial damage. Pilot lost control while positioning aircraft. Dynamic rollover occurred when a skid touched the ground.

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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