# NTSB SEA86FYE01: Jerome Dodge B-8-M, N4621N, Deer Park, WA, September 23, 1986

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: September 23, 1986, 13:00 local (20:00 UTC)
- Place: Deer Park, WA
- Coordinates: 47.989772, -117.499908 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=47.9898&lon=-117.4999&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 40309
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA86FYE01
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/40309/pdf
- Page: https://openairdocs.org/ntsb/SEA86FYE01

## Sequence of events

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

- Airframe/component/system failure/malfunction, approach - vfr pattern - downwind
  - flight controls - improper use of, pilot in command (cause)
  - design stress limits of aircraft - exceeded, pilot in command (cause)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE GYROCOPTER WAS OBSERVED OSCILLATING IN FLIGHT PRIOR TO DESCENDING TO GROUND IMPACT. INVESTIGATION REVEALED INFLIGHT CONTACT BETWEEN THE MAIN ROTOR AND VERTICAL FIN/PUSHER PROPELLER HAD TAKEN PLACE. NO MECHANICAL FAILURE WAS FOUND WHICH WOULD HAVE RESULTED IN THE CONTACT.

## Aircraft

- Registration: N4621N (not matched to a registry record)
- Reported make and model: JEROME DODGE B-8-M
- Category: Gyroplane, amateur-built
- Serial number: 43146739
- Engines: McCulloch 4318A reciprocating
- Damage: Destroyed
- Flight: Personal, Part 91
- Registered owner: Dana W. Dibble
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, October 5, 1985
- Departed: 07S, DEER PARK, WA
- Airport: 075, Deer Park, runway 16, 6,100 × 75 ft, grass/turf

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 31; student; medical: class 3, valid medical--no waivers/lim.; seat: front; toxicology performed; flight hours: 69 total, 46 in this make and model, 50 as pilot in command, 6 in the last 90 days, 3 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 190° at 14 knots
- Visibility: 20 statute miles
- Lowest ceiling: 12,000 ft broken
- Temperature: 63 °F, dew point 36 °F
- Altimeter: 29.00 inHg
- Observed at: SFF, 17 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 19860923046129A](https://openairdocs.org/incident/19860923046129A), Sep 23, 1986: Amtrbx BENSENB8M, Deer Park, WA, Destroyed. The gyrocopter began oscillating and main rotors cut off the tail. Aircraft fell vertically to ground impact.

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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