# NTSB NYC88LA090: Stinson 108, N6939M, Oswego, NY, February 18, 1988

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: February 18, 1988, 17:00 local (21:00 UTC)
- Place: Oswego, NY
- Coordinates: 43.449733, -76.499267 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=43.4497&lon=-76.4993&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report September 25, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 36103
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC88LA090
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/36103/pdf
- Page: https://openairdocs.org/ntsb/NYC88LA090

## 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, cruise - normal
  - engine assembly,connecting rod bolt - missing (cause)
  - engine assembly,connecting rod cap - loose (cause)
  - engine assembly,connecting rod - failure,total (cause)
  - engine assembly,crankcase - penetrated (cause)
- Forced landing, descent - emergency
- Nose over, landing - roll
  - terrain condition - snow covered (contributing factor)

## Analysis

DURING A LOCAL PLEASURE FLIGHT, A DECREASE IN ENGINE POWER WAS EXPERIENCED AND A PUFF OF SMOKE OBSERVED IN THE COCKPIT. THE PILOT APPLIED FULL POWER IN AN ATTEMPT TO RETURN TO THE AIRPORT, BUT REALIZED IT WAS NOT POSSIBLE. THE PILOT PUT THE AIRCRAFT DOWN IN AN OPEN SNOW COVERED FIELD. DURING THE LANDING ROLL OF ABOUT 125 FEET, THE AIRCRAFT FLIPPED OVER. THE CAUSE OF THE POWER LOSS WAS A BROKEN CONNECTING ROD ON THE #5 CYLINDER AND A NUT ON THE ROD END CAP HAD COME OFF.

## Aircraft

- Registration: [N6939M](https://openairdocs.org/aircraft/N6939M), registered now, S/N 108-4939, built 1950 (OpenAirDocs)
- Reported make and model: STINSON 108
- Registry model: [Stinson 108-3](https://openairdocs.org/model/stinson-108-3) (registry code 9230408) (OpenAirDocs)
- Registry engine: [Franklin 6A4165 series](https://openairdocs.org/engine/franklin-6a4165-series) (registry code 27025, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 180-4939
- Airframe hours: 1178
- Engines: FRANKLIN 6A4-150 150 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Robert Lyman
- Registered owner: Robert J Lyman
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, June 6, 1987
- Departed: NOO, FULTON, NY

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 57; student; medical: class 3, valid medical--w/ waivers/lim; seat: front; flight hours: 100 total, 100 in this make and model, 61 as pilot in command, 11 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 240° at 8 knots, gusting 8
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 39 °F
- Altimeter: 29.00 inHg

## 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 19880218002779A](https://openairdocs.org/incident/19880218002779A), Feb 18, 1988: Univar 1083, Oswego, NY, Substantial damage. Connecting rod failed. Flipped over on forced landing in a snow covered field.

## Other investigations on N6939M (1)

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.

- [NTSB CEN09LA384](https://openairdocs.org/ntsb/CEN09LA384), Jun 24, 2009: Stinson 108-3 (N6939M), Llano, TX, substantial damage. Probable cause: The pilot's inability to maintain aircraft control due to the failure of the left main landing gear wheel, which resulted in the separation of the wheel from the aircraft.

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.