NTSB Factual Report

On July 30, 2004, about 1900 central daylight time, an experimental amateur-built Tjerrild Rotorway Exec helicopter, operated by a private pilot, sustained substantial damage on impact with terrain and crops during a forced landing, following an in-flight loss of engine power near Eureka, Illinois. The personal flight was operating under 14 CFR Part 91. Visual meteorological conditions prevailed at the time of the accident. No Flight plan was on file. The pilot and passenger were uninjured. The local flight originated near Eureka, Illinois, and was in cruise flight at the time of the loss of engine power.

The pilot stated:

Took off from Eureka College ball field toward the South. Executed

climbing left hand turn around to a heading of [approximately] 360

[degrees] and up to 1000 MSL [feet above mean sea level].

Established level cruise at 1000 MSL and 70 mph. Engine stopped

without warning. Executed an auto rotate into corn field below. As

main rotors entered corn the aircraft yawed left and stopped partially

tipped over on left side. No injuries. Accident site [approximately] 1

mile from take-off point.

A Federal Aviation Administration Inspector performed an inspection of the wreckage. The high-tension wire from the ignition coil was found detached.

Rotorway International issued a service bulletin dated May 15, 1992 on the helicopter's ignition system. That service bulletin stated:

TO ALL EXEC BUILDERS

EXEC MANDATORY/ADVISORY SERVICE BULLETIN A-07

History: Electronic Ignition Systems have proven to be more

reliable and easier to maintain than conventional distributor

ignitions.

Action: For Exec helicopters, RotorWay International recommends

ONLY the Dual electronic Ignition system as equipped on our R.I.

162 engines. This system features two completely independent

ignition systems, including two spark plugs per cylinder, designed

to operate simultaneously. Either ignition system will support

full power performance. We recommend only this ignition system

and will no longer sell or support distributor ignitions. The dual

electronic ignition system may be fitted to any Exec with the RW 145

or RW 152 engine, and is strongly recommended. If you have

purchased a rebuilt distributor from RotorWay International, the

conversion to the dual electronic ignition system is regarded as

mandatory.

The accident helicopter was not modified with that service bulletin.

NTSB Probable Cause

The in-flight loss of engine power due to the disconnection of the high tension wire from its ignition coil during cruise flight and the unsuitable terrain the pilot encountered during his forced landing. A factor was the low altitude the helicopter was cruising at when the power loss occured.