# NTSB DEN92LA017: Stinson 108-1, N97962, Longmont, CO, December 22, 1991

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: December 22, 1991, 13:30 local (20:30 UTC)
- Place: Longmont, CO
- Location: 40.1682° N, 105.1005° W: Placed by OpenAirDocs: center of Longmont, CO, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=40.1682&lon=-105.1005&mi=10
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 3 minor
- Status: Completed, report April 8, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 18185
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN92LA017
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18185/pdf
- Page: https://openairdocs.org/ntsb/DEN92LA017

## Probable cause

A LOSS OF ENGINE POWER DUE TO FOULED SPARK PLUGS. THE INADEQUATE MAINTENANCE OF THE ENGINE WAS A FACTOR IN THE ACCIDENT.

## 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
  - ignition system,spark plug - fouled (contributing factor)
  - maintenance - inadequate, pilot in command (contributing factor)
- Forced landing, descent - emergency
- On ground/water encounter with terrain/water, landing - roll
  - object - fence
  - terrain condition - ditch
- Nose over, landing - roll

## Analysis

ON INITIAL CLIMB FOLLOWING TAKEOFF, AT A GROSS WEIGHT APPROXIMATELY 50 POUNDS OVER MAXIMUM, THE AIRPLANE WOULD NEITHER CLIMB NOR ACCELERATE. AFTER TURNING CROSSWIND AT 250 FEET AGL AND 1/2 MILE BEYOND THE RUNWAY END, ENGINE RPM BEGAN  TO 'CREEP DOWN.'  THE PILOT WAS UNABLE TO RESTORE RPM, THEREFORE, A FORCED LANDING WAS PERFORMED IN A PASTURE.  THE AIRPLANE COLLIDED WITH A DITCH AND FENCE, NOSED OVER, AND CAUGHT FIRE.  AN ENGINE EXAMINATION REVEALED THAT THE SPARK PLUGS WERE FOULED, MAGNETO IMPULSE COUPLING WEAK, AND RUST AND EVIDENCE OF DETONATION WAS PRESENT IN THE CYLINDERS AND ON PISTON DOMES, WHICH DEGRADED POWER AVAILABLE.

## Aircraft

- Registration: [N97962](https://openairdocs.org/deregistered/N97962-1992-04-21), registration cancelled 1992-04-21, S/N 108962 (OpenAirDocs)
- Reported make and model: STINSON 108-1
- Registry model: [Stinson 108-1](https://openairdocs.org/model/stinson-108-1) (registry code 9230404) (OpenAirDocs)
- Category: Airplane
- Serial number: 108-962
- Airframe hours: 2391
- Engines: FRANKLIN GA4-150-B3 150 horsepower reciprocating
- Damage: Destroyed
- Fire: On-Ground
- Flight: Personal, Part 91
- Operator: Donald Badtram/Stephen Innes
- Registered owner: Donald Badtram/Stephen Innes
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, June 11, 1991
- Destination: EMD, EMPORIA, KS

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 41; private; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 2,650 total, 35 in this make and model, 2,630 as pilot in command, 25 in the last 90 days, 5 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 260° at 5 knots
- Visibility: 75 statute miles
- Lowest ceiling: 22,000 ft overcast
- Temperature: 39 °F, dew point 18 °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 19911222057009A](https://openairdocs.org/incident/19911222057009A), Dec 22, 1991: Univar 1081, Longmont, CO, Destroyed. Over gross high altitude. Unable climb on takeoff. Hit ditch and fence. Fouled plugs,busted cylinders detonation.

## Other investigations on N97962 (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 DEN76FTE38](https://openairdocs.org/ntsb/DEN76FTE38), Nov 4, 1975: Stinson 108-1 (N97962), Peyton, CO, substantial damage

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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