Bell 47D1 N78900

Summary

On 28 June 2013 at about 17:20 local time, a Bell 47D1 registered N78900, operated by Lake Ozark Helicopters Inc, was involved in an accident near Lake Ozark, Missouri, United States. 2 people were on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

28 June 2013 at 17:20

Classification

Accident

Location

Lake Ozark, Missouri, United States

Coordinates

38.1810, -92.6210

Aircraft

Bell 47D1

Registration

N78900

Category

Helicopter

Engines

1

Operator

Lake Ozark Helicopters Inc

Operating rule

Part 91: General Aviation

Purpose of flight

Other Work Use

Phase of flight

Not recorded

Route

Lake Ozark → Lake Ozark

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CEN13LA396

Nobody was injured.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.