Cessna 172B accident near Unionville, Iowa, February 25, 1989
On February 25, 1989 at about 8:45 pm local time, a Cessna 172B, registered N7662X, was substantially damaged in an accident near Unionville, Iowa. It was a personal flight under general aviation rules (Part 91). No one was hurt; 3 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- February 25, 1989 · about 8:45 pm local time
- Place
- Unionville, Iowa · map
- Type
- Accident
- Injuries
- No one was hurt; 3 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 172B · all 172Bs on the register
- Registration
- N7662X · no longer on the register · serial 17248162
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot, flight instructor, military
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 11,475 hours in all; 490 in this make and model; 105 in the last 90 days; 15 in the last 30 days; 3,360 as pilot in command; 1,480 on instruments
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 3,050 hours
- Last inspection: annual inspection, November 14, 1988; 5 hours since
- Maximum gross weight: 2,200 lb
- Seats: 4
- Landing gear: fixed
- Engine: Continental O-300-D (piston); 0 hours total
The flight
- Departed from: K27 Ft. Madison IA at 8:00 pm
- Destination: K27 Osceola IA
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 120° at 7 knots
- Visibility: 12 statute miles
- Sky: broken clouds at 25,000 ft; scat at 12,000 ft
- Temperature: 43°F (6°C), dew point 30°F (-1°C)
- Altimeter: 29.00 inHg
- Observation at 8:50 pm from OTM, 15 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.