WPR24LA081

In cruise flight, the pilot noticed a warning indication from the airplane’s avionics display alerting him to a loss of electrical power. Immediately following, the avionics display went dark, followed by a total loss of engine power. The pilot attempted to restore electrical power; however, neither the primary nor secondary electrical power was restored. He initiated a forced landing to a field, during which the airplane sustained substantial damage. The airplane was equipped with an electronic fuel injection and ignition system that required continuous electrical power to operate. Although the airplane was equipped with dual electrical systems for redundancy, both systems shared a common ground. Examination revealed a loose connection between a common ground feed-through stud and the ground bus. This loose connection likely resulted in the loss of electrical power to core aircraft systems, and the subsequent total loss of engine power. No other anomalies were noted with the wreckage that would have precluded normal operation.

On January 30, 2024, about 1317 Pacific standard time, an experimental, amateur-built Raptor Junior 540, N906CR, was substantially damaged when it was involved in an accident near Camarillo, California. The pilot received serious injuries and the pilot-rated passenger received minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, the flight departed Santa Monica Airport, Santa Monica, California, enroute to Camarillo Airport (CMA), Camarillo, California, to conduct touch-and-go landings. About 5 miles southeast of CMA, the pilot noticed a warning indication on the airplane’s avionics display alerting him to a loss of electrical power. He stated that within seconds, the entire display, excluding the Dynon Primary Flight Display, which had a backup battery, “went blank,” followed by a total loss of engine power. The pilot performed emergency procedures to restore electrical and engine power but was unsuccessful. The pilot performed a forced landing to an agricultural field about 4.5 miles southeast of CMA, during which the airplane sustained substantial damage. The airplane was equipped with an electronic fuel injection and ignition system, manufactured by EFII Systems. Electrical system redundancy was accomplished by use of a main and auxiliary system, with two independent batteries and an alternator. The system shared a common ground line that connected the negative terminals for both batteries and was routed through a ground bus located behind the nose cone bulkhead to the engine compartment and engine case. Postaccident examination of the wreckage revealed that the ground feed-through stud that connected the battery ground terminals to the ground bus was loosely connected on the nose cone bulkhead. The feed-through nut was 3.5 turns loose, which corresponded to approximately 3.5 threads of the feed-through stud. (See figure 1.) Additionally, neither a spring lock washer nor a secondary locking nut were present on the feed- through stud assembly, as was found on all other primary electrical connections throughout the airplane. Figure 1. Common ground feed-through stud loosely connected to ground bus. Examination of the engine revealed no preaccident mechanical malfunctions or failures that would have precluded normal operation.