Bell 47B3 N11HU

Summary

On 16 February 1990 at about 14:30 local time, a Bell 47B3 registered N11HU, operated by Zimlock Helicopters, was involved in an accident near Redlands, California, United States. One person was on board and nobody was injured. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

16 February 1990 at 14:30

Classification

Accident

Location

Redlands, California, United States

Coordinates

Not recorded

Aircraft

Bell 47B3

Registration

N11HU

Category

Helicopter

Engines

1

Operator

Zimlock Helicopters

Operating rule

Part 91: General Aviation

Purpose of flight

Business

Phase of flight

Not recorded

Aircraft damage

Destroyed

Weather

VMC

Light

Dawn

NTSB number

LAX90LA095

Nobody was injured.

FAILURE OF THE PILOT TO USE CARBURETOR HEAT WHEN WARRENTED BY CONDITIONS.

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

Read the full NTSB narrative

THE OPERATOR BORROWED THE HELICOPTER FROM THE OWNER UNDER A VERBAL STIPULATION THAT AUTOMOTIVE FUEL WOULD NOT BE USED. THE ACCIDENT HELICOPTER WAS NOT APPROVED FOR AUTOMOTIVE GASOLINE UNDER THE PROVISIONS OF AN STC. HOWEVER, THE OPERATOR WAS KNOWN TO REFUEL HIS HELICOPTERS WITH AUTO GAS. THE PURPOSE OF THE FLIGHT WAS TO ERADICATE FROST FROM CITRUS TREES. AFTER REFUELING, THE HELICOPTER LOST POWER AND DESCENDED STRIKING WIRES AND TREES. THE OPERATOR DRAINED THE FUEL FROM THE HELICOPTER ON THE GROUND AND TRANSPORTED IT TO HIS FACILITY. THE ACCIDENT WAS REPORTED FOUR DAYS LATER. EXAMINATION OF THE FUEL SYSTEM REVEALED A SMALL QUANTITY OF FUEL WITH EVIDENCE OF AUTO GAS. LABORATORY ANALYSIS OF FUEL SAMPLE REVEALED SAMPLE HAD THE SAME AROMATIC QUALITIES AS AUTO GAS. ACCORDING TO THE FAA, THE ONSET OF CARBURETOR ICE WILL OCCUR QUICKER WITH AUTO GAS THAN WITH AVIATION FUEL. WEATHER CONDITIONS WERE CONDUCIVE TO FROST FORMING ON FRUIT TREES.

Quoted verbatim from the NTSB record.