Bell 47G-3B-1 N3377H

Summary

On 2 April 2000 at about 18:50 local time, a Bell 47G-3B-1 registered N3377H, operated by Gable, Stephen, L., was involved in an accident near Stanwood, Washington, United States. 3 people were on board and one died, one was seriously injured, one had minor injuries. The aircraft was destroyed. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

2 April 2000 at 18:50

Classification

Accident

Location

Stanwood, Washington, United States

Coordinates

48.2104, -122.2794

Aircraft

Bell 47G-3B-1

Registration

N3377H

Category

Helicopter

Engines

1

Operator

Gable, Stephen, L.

Operating rule

Part 91: General Aviation

Purpose of flight

Unknown

Phase of flight

Not recorded

Route

Arlington → Unknown

Aircraft damage

Destroyed

Weather

VMC

Light

Day

NTSB number

SEA00FA061

1 person died.

The disengagement of the oil jet fitting from its threaded receptacle at the forward end of the engine crankshaft. This resulted in excessive oil within the clutch assembly, the subsequent slipping of the clutch, and ultimately the disengagement of the rotor drive system from the engine. Contributing factors were the pilot's not maintaining clearance from the electric fences which were also hidden objects against the grass landing surface.

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

Read the full NTSB narrative

The pilot and two passengers were engaged in a sightseeing flight eastbound over a river in the Bell 47G helicopter when they heard a 'clunk,' the engine began to overspeed, and rotor RPM began to decay. The pilot executed an autorotation to a nearby field. Just prior to touchdown, the helicopter snagged the wires of two low profile, four-foot high electrical fences which he did not see. The helicopter then rolled/yawed to the right and made a hard landing, coming to rest on its right side. Post-crash examination of the engine and transmission revealed no mechanical malfunctions. However, the oil jet (a threaded, hollow plug which screwed into the forward end of the engine crankshaft) was found lying loose beneath the clutch housing. The interior surfaces of the clutch housing displayed a large amount of oil. The clutch assembly was found to be without mechanical disparities and within normal wear limits. The release of the oil jet would have allowed engine oil to flow through the 3/8 inch threaded orifice into the lower transmission and clutch housing at a significantly higher rate than through the small diameter orifice in the end of the oil jet, resulting in disengagement of the clutch. The orifice in the jet was intended to allow a mist or light spray of oil to reach the lower mast bearing for lubrication purposes.

Quoted verbatim from the NTSB record.