Bell 47D1 accident near Lake Ozark, Missouri, June 28, 2013
On June 28, 2013 at about 5:20 pm local time, a Bell 47D1 (helicopter), registered N78900, was substantially damaged in an accident during enroute (cruise) near Lake Ozark, Missouri. It was an other work-use flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The improper rebuild and maintenance of the helicopter and inadequate subsequent inspections, which resulted in undetected fuel contamination and a subsequent total loss of engine power during cruise flight.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 28, 2013 · about 5:20 pm local time
- Place
- Lake Ozark, Missouri · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47D1 · all 47D1s on the register
- Registration
- N78900 · registry record · serial 480
- Damage
- Substantial damage
- Flight
- Other work-use flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot stated that, during the preflight inspection, he observed no contamination in the fuel sumped from the helicopter. During the helicopter's second air tour flight of the day, it experienced a total loss of engine power during cruise flight. The pilot performed an autorotation to a field, which resulted in damage to the tailboom and main rotor blade. The helicopter had been in a previous accident and was subsequently rebuilt; it was sold to the operator about 6 months before the accident. During the rebuild, parts were sand and bead blasted. The pilot stated that, about 2 months before the accident, fuel samples from the helicopter showed contamination. He described the contaminated fuel as "discolored…from sitting." The operator drained and replaced the fuel, ran the engine on the ground, and performed numerous sumps until the fuel was "clean" and up to the operator's standards. The helicopter was then flown for about 12 hours before the accident flight occurred. During postaccident examinations, a substance consistent with silicon-glass blasting was found within the carburetor bowl, carburetor screen, and fuel sump. No other anomalies were found that would have precluded normal operation of the helicopter. It is likely that the fuel was contaminated by the blasting substance at the time of the rebuild and that the substance was not found during subsequent preflight inspections, which resulted in a total loss of engine power during cruise flight.
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
What happened, in order
- Autorotation Off-field or emergency landing
- Hard landing during landing (flare/touchdown)
- Collision with terrain or object (not controlled flight into terrain) during landing (flare/touchdown)
- Aircraft maintenance event during prior to flight
- Fuel contamination during enroute (cruise) defining event
The NTSB's findings
- cause Aircraft › Aircraft handling/service › Maintenance/inspections › (general) › Incorrect service/maintenance
- cause Aircraft › Aircraft systems › Fuel system › (general) › Incorrect service/maintenance
- cause Aircraft › Fluids/misc hardware › Fluids › Fuel › Fluid condition
- cause Aircraft › Aircraft power plant › (general) › (general) › Malfunction
Pilot
- Certificate: commercial pilot
- Ratings: instructor: helicopter; instrument: helicopter; rotorcraft: helicopter
- Flight time: 638 hours in all; 19 in this make and model; 212 in the last 90 days; 108 in the last 30 days; 581 as pilot in command; 66 on instruments
- Last flight review: December 5, 2012
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 7,653 hours
- Last inspection: 100-hour inspection, March 1, 2013
- Maximum gross weight: 2,350 lb
- Seats: 2
- Landing gear: fixed
- Engine: Franklin 6V4 (piston); 0 hours total
- Operator: Lake Ozark Helicopters Inc
The flight
- Departed from: Lake Ozark MO at 4:10 pm
- Destination: Lake Ozark MO
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 340° at 6 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 84°F (29°C), dew point 64°F (18°C)
- Altimeter: 29.86 inHg
- Observation at 7:55 pm from AIZ, 10 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
18 documents, released by the NTSB on February 5, 2014. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Other NTSB records under N78900 the same tail number, which may have belonged to a different aircraft at the time
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.