NTSB Factual Report

On June 14, 2003, about 1320 eastern daylight time, a Zenith 601HDS amateur-built airplane, N601G, registered to and operated by a private individual, as a Title 14 CFR Part 91 personal flight, had the engine cease operating while in flight in Immokalee, Florida. Visual meteorological conditions prevailed and no flight plan was filed. The private-rated pilot received minor injuries and the airplane incurred substantial damage. The flight originated in Naples, Florida, the same day about 1300.

The pilot/owner stated that he is the builder of the airplane, and was in cruise flight, at an altitude of 2,900 feet, operating on the flywheel-triggered ignition system, collecting performance data. He said he began a descent, and at 2,600 feet, about 5.6 miles from his destination, the engine suddenly ceased operating. He said he switched to the distributor ignition, observed normal fuel pressure and verified that there was adequate fuel in the header tank. He said he then communicated his emergency to air traffic control, and again attempted to restart the engine using the starter with both ignitions, but was unable to get the engine to start. He then made an approach to land in a field and during the landing rollout, the airplane flipped over due to the soft muddy soil, incurring substantial damage to the aircraft.

The pilot/owner stated that after the accident he examined the airplane to determine the reason the engine had ceased to operate, and he found that the distributor rotor had failed due to excessive shaft clearance. He said that the excessive clearance had allowed the rotor to wobble in its rotation, and contact the pins within the cap, which had resulted in the metal contact at the top, separating from the plastic base.

NTSB Probable Cause

Excessive rotor distributor shaft clearance that resulted in damage to the distributor rotor, a loss of ignition, the engine ceasing to operate. This resulted in a forced landing to unsuitable terrain and the airplane nosing over.