Hiller UH-12D accident near Soddy-Daisy, Tennessee, March 31, 1990
On March 31, 1990 at about 6:38 pm local time, a Hiller UH-12D (helicopter), registered N94496, was substantially damaged in an accident near Soddy-Daisy, Tennessee. It was a personal flight under general aviation rules (Part 91). 1 person was killed, 1 person was seriously injured and 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
FATIGUE INDUCED FAILURE OF THE COLLECTIVE PITCH PUSH ROD (ADJUSTABLE) DURING FLIGHT, AND THE FAILURE OF THE PILOT TO PROVIDE ROUTINE MAINTENANCE. THE PILOT'S LACK OF EXPEREINCE AND HIS FAILURE TO OBTAIN REQUIRED TRAINING AND CERTIFICATION WERE FACTORS IN THE ACCIDENT.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 31, 1990 · about 6:38 pm local time
- Place
- Soddy-Daisy, Tennessee · map
- Type
- Accident
- Injuries
- 1 person was killed, 1 person was seriously injured and 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Hiller UH-12D · all UH-12Ds on the register
- Registration
- N94496 · no longer on the register · serial 1341
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
SHORTLY AFTER TAKEOFF, THE PILOT OBSERVED DECREASING ENGINE AND ROTOR RPM. HE LOWERED THE COLLECTIVE, BUT THE RPM DID NOT RETURN. THE HELICOPTER COLLIDED WITH TREES AND TERRAIN DURING THE FORCED LANDING ATTEMPT. AN INSPECTION OF THE HELICOPTER REVEALED THAT THE COLLECTIVE PITCH PUSH ROD (ADJUSTABLE) HAD FAILED IN FATIGUE. THE LAST RECORDED MAINTENANCE WAS PERFORMED ON FEBRUARY 22, 1988, MORE THAN TWO YEARS PRIOR TO THE ACCIDENT. THE PILOT/OWNER WAS OPERATING THE HELICOPTER WITH A STUDENT PILOT CERTIFICATE AND WAS CARRYING PASSENGERS.
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: student
- Flight time: 46 hours in all; 30 in this make and model
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: ctr
The aircraft
- Airframe total time: 6,125 hours
- Last inspection: inspection type not recorded; 30 hours since
- Maximum gross weight: 2,750 lb
- Seats: 3
- Landing gear: retractable
- Engine: Lycoming O-435-A1C (piston); 0 hours total
The flight
- Departed from: NONE Hixson TN at 6:37 pm
- Destination: NONE
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 180° at 5 knots
- Visibility: 12 statute miles
- Sky: scat at 25,000 ft
- Temperature: 70°F (21°C), dew point 57°F (14°C)
- Altimeter: 29.00 inHg
- Observation at 6:50 pm from CHA, 13 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 1 | 1 |
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.