# NTSB NYC92DEG01: Devenport EAA Biplane, N9601, Wilksville, OH, December 16, 1991

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Final report
- Date: December 16, 1991, 16:10 local (21:10 UTC)
- Place: Wilksville, OH
- Coordinates: 39.159641, -82.369445 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.1596&lon=-82.3694&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report April 23, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 37028
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC92DEG01
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/37028/pdf
- Page: https://openairdocs.org/ntsb/NYC92DEG01

## Probable cause

THE RESTRICTED VISIBILITY OF THE PILOT DUE TO OIL ON THE WINDSHIELD AND HIS GOGGLES, WHICH RESULTED IN A TREE STRIKE AND UNCONTROLLED TOUCHDOWN, DURING THE EXECUTION OF A PRECAUTIONARY LANDING.  FACTORS RELATED TO THE ACCIDENT WERE A CLOGGED CRANKCASE BREATHER TUBE, THE LACK OF A WHISTLE SLOT ON THE CRANKCASE BREATHER TUBE, AND THE TREES.

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise - normal
  - weather condition - icing conditions
  - engine assembly,crankcase - leak (contributing factor)
- In flight collision with object, approach - vfr pattern - final approach
  - visual lookout - restricted, pilot in command (cause)
  - precautionary landing - performed, pilot in command
  - object - tree(s) (contributing factor)
- In flight collision with terrain/water, descent - uncontrolled
  - remedial action - not possible, pilot in command

## Analysis

THE PILOT WAS IN CRUISE FLIGHT, IN AN EXPERIMENTALLY CERTIFIED AIRPLANE, WHEN THE CRANKCASE BREATHER WHICH WAS NOT PRESSURIZED WITH A WHISTLE SLOT FROZE UP.  THE CRANKCASE PRESSURIZED AND THE CRANKCASE SEAL WAS DISLODGED. THE PILOT MADE A PRECAUTIONARY LANDING IN A FIELD OF LIMITED SIZE, SURROUNDED BY TREES.  DUE TO THE RESTRICTED VIIBILITY OF THE PILOT, WITH OIL ON HIS GOGGLES AND WINDSHIELD, HE STRUCK A TREE ON FINAL AND MADE AN UNCONTROLLED TOUCHDOWN IN THE FIELD.  THE INVESTIGATION REVEALED THERE IS A REQUIREMENT OF A WHISTLE SLOT ON NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES, HOWEVER, THIS REQUIREMENT DOES NOT EXIST FOR EXPERIMENTAL CATEGORY AIRPLANES.

## Aircraft

- Registration: [N9601](https://openairdocs.org/deregistered/N9601-1998-04-29), registration cancelled 1998-04-29, S/N 1 (OpenAirDocs)
- Reported make and model: DEVENPORT EAA BIPLANE (EAA BIPLAN)
- Registry model: [Davenport EAA BIPLANE](https://openairdocs.org/model/davenport-eaa-biplane) (registry code 33601A1) (OpenAirDocs)
- Category: Airplane, amateur-built
- Serial number: 1
- Airframe hours: 185
- Engines: LYCOMING O-290-D 70 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Jack F. Holgate
- Registered owner: Jack F. Holgate
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, June 24, 1991, 70 hours before
- Departed: LOZ, LONDON, KY
- Destination: UNI, ATHENS, OH
- Flight plan: VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 50; private; airplane ratings: single-engine land; medical: class 3, valid medical--w/ waivers/lim; flight hours: 189.5 total, 36 in this make and model, 151 as pilot in command, 36.7 in the last 90 days, 14.1 in the last 30 days, 3.2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: variable at 8 knots
- Visibility: 15 statute miles
- Lowest ceiling: 1,000 ft overcast
- Temperature: 36 °F
- Observed at: HTS, 50 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 19911216056379A](https://openairdocs.org/incident/19911216056379A), Dec 16, 1991: Amtrea EAABIPLANE*, Wilksville, OH, Substantial damage. Oil on windscreen and burning smell. Landed open field, struck tree. Ice plugged crankcase breather tube.

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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