Hiller UH-12E N689SB

Summary

On 11 October 1989 at about 02:27 local time, a Hiller UH-12E registered N689SB, operated by West Farm Air Inc., was involved in an accident near Yuma, Arizona, United States. One person was on board and one was seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

11 October 1989 at 02:27

Classification

Accident

Location

Yuma, Arizona, United States

Coordinates

32.6794, -114.6592

Aircraft

Hiller UH-12E

Registration

N689SB

Category

Helicopter

Engines

1

Operator

West Farm Air Inc.

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Somerton → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Night/Dark

NTSB number

LAX90DUJ03

1 person was seriously injured.

THE PILOT MISJUDGED THE FLARE ALTITUDE. CONTRIBUTING TO THIS ACCIDENT WAS THE FAILURE OF THE ENGINE TORSIONAL COUPLING WHICH ULTIMATELY CAUSED THE TOTAL LOSS OF POWER.

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

Read the full NTSB narrative

THE PILOT COMPLETED AN AERIAL APPLICATION OPERATION AT ABOUT 200 FT AGL WHEN HE NOTICED THE ENGINE RPM DECAYING. HE PROCEEDED TO AN OPEN AREA TO EXECUTE A PRECAUTIONARY LANDING. UPON ARRIVING OVER THE OPEN AREA AT ABOUT 100 FT AGL, THE ENGINE SUSTAINED A TOTAL LOSS OF POWER. THE PLT IMMEDIATELY EXECUTED AN AUTOROTATION, BUT FLARED TOO HIGH CAUSING THE TAIL ROTOR ASSEMBLY TO STRIKE THE GROUND. A WRECKAGE EXAM DSCLSD THAT THE ENGINE TORSIONAL COUPLING RUBBER MOUNTS HAD SEPARATED. THIS CONDITION CAUSED AN OVERSPEED WHICH ULTIMATELY SHUT DOWN THE ENGINE.

Quoted verbatim from the NTSB record.