# NTSB SEA86LA208: Curtiss JN4-D, N511JN, Vancouver, WA, August 17, 1986

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: August 17, 1986, 15:00 local (22:00 UTC)
- Place: Vancouver, WA
- Coordinates: 45.620773, -122.569244 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.6208&lon=-122.5692&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 2 minor
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 40475
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA86LA208
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/40475/pdf
- Page: https://openairdocs.org/ntsb/SEA86LA208

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, takeoff - initial climb
  - fuel system,carburetor - improper (cause)
  - fuel system,carburetor - cracked (cause)
- Forced landing, descent - emergency
- Hard landing, landing - flare/touchdown
  - proper descent rate - not possible, pilot in command (cause)
- Main gear collapsed, landing - roll

## Analysis

THE PLT REPORTED A NORMAL TAKEOFF WAS MADE WITH 1300 RPM. AT LIFTOFF A SMALL AMOUNT OF BLACK SMOKE EMITTED FROM BOTH EXHAUST STACKS AND THE RPM DROPPED TO 1250. AFTER CLEARING THE RWY, MORE BLACK SMOKE EMITTED AND THE RPM DROPPED TO 1200. THE PLT CLEARED TWO 40 FOOT TALL TREES AT THE END OF THE RWY AND MADE A HARD LANDING IN A FIELD BEYOND THE TREES. INVESTIGATION DISCLOSED THE FLOAT FROM THE ZENITH CARBURETOR HAD 17 VERITCAL LINES ON THE OUTSIDE DIAMETER AND CRACKS. THE FLOAT WAS FUEL SATURATED.

## Aircraft

- Registration: [N511JN](https://openairdocs.org/deregistered/N511JN-2025-05-05), registration cancelled 2025-05-05, S/N 5111 (OpenAirDocs)
- Reported make and model: CURTISS JN4-D
- Registry model: [Olson Waldo S JENNY JN4D](https://openairdocs.org/model/olson-waldo-s-jenny-jn4d) (registry code 05663BU) (OpenAirDocs)
- Category: Airplane
- Serial number: S11
- Airframe hours: 30
- Engines: LIBERTY OX-5 200 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Waldo S. Olson
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, June 1, 1986, 30 hours before
- Airport: 59S, Evergreen

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 75; commercial, flight instructor; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: rear; flight hours: 29,000 total, 30 in this make and model, 305 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 270° at 7 knots
- Visibility: 40 statute miles
- Lowest ceiling: 20,000 ft broken
- Temperature: 79 °F, dew point 52 °F
- Altimeter: 29.00 inHg
- Observed at: PDX

## 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 19860817073859A](https://openairdocs.org/incident/19860817073859A), Aug 17, 1986: Curtis JN4DJENNY, Vancouver, WA, Substantial damage. Engine developed problems during flight and the aircraft flipped over on landing. Fuel float was found leaking.

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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