Accident Overview
On September 4, 2023, at approximately 1100 central daylight time, an RV-14A airplane, registration N14NP, sustained substantial damage during a forced landing near Orchard, Texas. The pilot and a pilot-rated passenger were not injured. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal flight.
Flight Events
The pilot had purchased the airplane about one month before the accident. The flight departed from Fair Weather Field (TX42), Monaville, Texas, bound for Texas Gulf Coast Regional Airport (LBX), Angleton/Lake Jackson, Texas. Approximately 10 minutes into the flight, the pilot observed the left and right battery indications on the instrument panel turning on and off repeatedly. About 8 minutes later, the secondary EFIS and several other avionics lost electrical power, although the primary EFIS remained powered and the engine continued operating normally. The pilot turned back toward TX42 and flew for another 10 minutes until all electrical and engine power was lost. A forced landing was executed to a field, where the airplane came to rest upright.
Postaccident Examination
Postaccident examination revealed substantial damage to the fuselage. The No. 2 alternator belt was broken and found inside the engine cowling, which had black rubber marks on its interior surface. The No. 1 alternator belt remained intact. When tested with a multimeter, neither of the two batteries showed any voltage. The alternators were wired so that only the No. 2 alternator charged the batteries; this alternator operated as expected during testing. No other mechanical malfunctions or anomalies that could have caused a loss of electrical or engine power were identified. The airplane was equipped with an electronic ignition and injection system.
Pilot and Builder Statements
The pilot stated that the alternator indication lights were not wired to illuminate when the alternators were offline. According to the airplane builder, the ammeters displayed digitally on the EFIS indicated alternator functionality; a needle pointing up signified that the corresponding alternator was working. The builder had conveyed this to the pilot.
Recorded Data
The pilot provided EFIS data from the accident flight. The data showed that a battery alert first appeared at 1031, when the airplane's ground speed was about 3 knots. Approximately 20 seconds later, the ground speed increased, followed by an altitude increase consistent with takeoff. Intermittent battery alerts continued until about 1048. Additionally, the data indicated intermittent battery alerts during a 2-minute portion of an earlier flight on the same day.
Maintenance History
The airplane maintenance logbooks showed that the airplane was equipped with two EarthX ETX900 13.2-volt lithium batteries, installed by the builder. On April 18, 2018, at an airframe total time of 201.1 hours, the builder replaced the No. 2 alternator belt. The builder performed the most recent annual condition inspection on February 1, 2023, about seven months before the accident, at an airframe total time of 523.7 hours.