NTSB Factual Report

On April 21, 2006, about 1630 mountain daylight time, a Pitrolo GL-25 amateur built experimental airplane, N27EP, sustained substantial damage during a forced landing following a loss of engine power near Worden, Montana. The commercial pilot, the sole occupant, was not injured. The airplane was registered to and operated by the pilot. Visual meteorological conditions prevailed and no flight plan was filed for the local personal flight conducted under 14 CFR Part 91. The flight departed from Billings Logan International Airport, Billings, Montana, about 1500.

According to the pilot, the purpose of the flight was to "check out and become familiar with a recent instrument panel upgrade performed by the local avionics shop during the past several months." After about 90 minutes of flight time, the new digital horizon indicator "had an over temperature warning," which the pilot later found was set to warn when the "local environment (behind the instrument panel)" temperature reached 120 degrees F. Within a few minutes, the engine lost power. The pilot noted that the two 5-amp circuit breakers for the two electronic ignition systems had popped and could not be reset. During the ensuing forced landing in a wheat field, the main landing gear sank into the soft ground and the "landing gear sheared off."

Examination by the pilot and avionics shop personnel revealed a "dead short in each electronic ignition module." These modules were installed on the cabin side of the firewall as per the manufacturer's recommendation. The reason for the short circuits in the modules could not be determined; however, the pilot suspected "a heat related issue."

NTSB Probable Cause

The loss of engine power due to failure of both electronic ignition systems. A contributing factor was the lack of suitable terrain for the forced landing.