Bell 47J2A N470RA

Summary

On 19 June 1995 at about 19:40 local time, a Bell 47J2A registered N470RA was involved in an accident near Elkhorn, Wisconsin, 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

19 June 1995 at 19:40

Classification

Accident

Location

Elkhorn, Wisconsin, United States

Coordinates

42.6690, -88.5408

Aircraft

Bell 47J2A

Registration

N470RA

Category

Helicopter

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

East Troy → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

CHI95LA187

Nobody was injured.

loss of power as a result of an intake valve failure due to improper maintenance performed during the major engine overhaul, and pilot misjudgment of the flare during autorotation.

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

Read the full NTSB narrative

THE PILOT REPORTED THAT HE WAS CRUISING AT ABOUT 1,000 FEET WHEN THE ENGINE LOST POWER. AN AUTOROTATION WAS INITIATED. DURING THE LANDING PHASE (CYCLIC FLARE), THE MAIN ROTOR STRUCK THE TAILROTOR DRIVE SHAFT. AN EXAMINATION OF THE ENGINE REVEALED THAT THE NUMBER TWO CYLINDER INTAKE VALVE HAD FAILED IN THE TOP RADIUS (NECK AREA) OF THE VALVE KEEPER RECESS, CAUSING DAMAGE TO THE CYLINDER COMBUSTION CHAMBER AND PISTON. AN INSPECTION OF THE ENGINE LOGBOOKS INDICATED THAT AN IDENTICAL FAILURE HAD OCCURRED EIGHT HOURS PREVIOUSLY. FURTHER INSPECTION REVEALED THAT THE MAJOR ENGINE OVERHAUL, WHICH HAD BEEN CONDUCTED 27 HOURS PRIOR TO THE ACCIDENT, HAD NOT BEEN PERFORMED IN ACCORDANCE WITH THE MANUFACTURER'S PROCEDURES AND SPECIFICATIONS.

Quoted verbatim from the NTSB record.