# NTSB MKC89LA064: Cessna 172B, N7662X, Unionville, IA, February 25, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: February 25, 1989, 14:45 local (20:45 UTC)
- Place: Unionville, IA
- Coordinates: 40.810924, -92.689964 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=40.8109&lon=-92.6900&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed, report January 11, 1990
- Report: Approved by Office Director
- NTSB case key (mKey): 34754
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=MKC89LA064
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/34754/pdf
- Page: https://openairdocs.org/ntsb/MKC89LA064

## Probable cause

THE FAILURE OF THE ENGINE DUE TO CARBURETOR ICE. CONTRIBUTING FACTORS INCLUDED CARBURETOR ICING CONDITIONS, IMPROPER USE OF THE CARBURETOR HEAT CONTROL BY THE PILOT, AND THE IMPROPERLY RIGGED CARBURETOR AIR BOX WHICH RESULTED IN REDUCED CARBURETOR HEATING CAPABILITY.

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, cruise
  - weather condition - carburetor icing conditions (contributing factor)
  - fuel system,carburetor - ice (cause)
  - carburetor heat - improper use of, pilot in command (contributing factor)
  - carburetor heat control - inadequate (contributing factor)
  - maintenance,modification - improper, other maintenance personnel (contributing factor)
- Forced landing, descent - emergency
- In flight collision with terrain/water, landing - flare/touchdown
  - terrain condition - snow covered (contributing factor)
  - terrain condition - ditch (contributing factor)

## Analysis

THE PILOT SAID THAT WHILE CRUISING TO HIS DESTINATION APT, THE ENGINE QUIT SUDDENLY. EMERGENCY PROCEDURES FAILED TO RECTIFY THE POWER LOSS AND AN EMERGENCY LANDING WAS ATTEMPTED ON A SNOW COVERED FARM FIELD. A COLLISION WITH A DITCH TORE OFF THE NOSE GEAR AND THE AIRCRAFT CONTINUED TO SLIDE ABOUT 300 FEET, COMING TO STOP ON IT'S NOSE. POST ACCIDENT INVESTIGATION REVEALED THE CARB HEAT BOX TO BE IMPROPERLY RIGGED AND A SEAL MISSING FROM THE FLAPPER VALVE. METEOROLOGICAL CONDITIONS AT THE TIME WERE CONDUCIVE FOR CARB ICING ACCORDING TO ICING PROBABILITY CHARTS. THE MIS-RIGGING OF THE CARB HEAT BOX PREVENTED FULL APPLICATION OF CARB HEAT. AFTER THE ENGINE QUIT THE PILOT ATTEMPTED TO RESTORE POWER WITH CARB HEAT BUT WAS UNABLE.

## Aircraft

- Registration: [N7662X](https://openairdocs.org/deregistered/N7662X-1991-04-29), registration cancelled 1991-04-29, S/N 17248162 (OpenAirDocs)
- Reported make and model: CESSNA 172B
- Registry model: [Cessna 172B](https://openairdocs.org/model/cessna-172b) (registry code 2072406) (OpenAirDocs)
- Category: Airplane
- Serial number: 17248162
- Airframe hours: 3050
- Engines: CONTINENTAL O-300-D 145 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Morton, Dennis D.
- Airworthiness certificate: Standard, Utility; Standard, Normal
- Last inspection: Annual, November 14, 1988, 5 hours before
- Departed: K27, FT. MADISON, IA
- Destination: K27, OSCEOLA, IA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 41; airline transport, military, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 11,475 total, 490 in this make and model, 3,360 as pilot in command, 105 in the last 90 days, 15 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 120° at 7 knots
- Visibility: 12 statute miles
- Lowest ceiling: 25,000 ft broken
- Temperature: 43 °F, dew point 30 °F
- Altimeter: 29.00 inHg
- Observed at: OTM, 15 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 19890225002659A](https://openairdocs.org/incident/19890225002659A), Feb 25, 1989: Cessna 172B, Unionville, IA, Substantial damage. Engine quit en route. Hit a ditch on forced landing. Carb heat box rigged improperly,partly open caused carb icing

## Other investigations on N7662X (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 MKC66D0289](https://openairdocs.org/ntsb/MKC66D0289), Sep 8, 1965: Cessna 172 (N7662X), Festus, MO, 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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