History of Flight
On October 30, 2017, at approximately 1416 Pacific daylight time, a Vans Aircraft RV-6 experimental amateur-built airplane, registration N88MV, struck a fence in a vineyard during a forced off-airport landing near Selma, California. The airline transport pilot, who was also the operator, was uninjured. The wings and fuselage incurred substantial damage. The flight, conducted under Title 14 Code of Federal Regulations Part 91 as a personal operation, originated from Fresno Chandler Executive Airport (FCH) around 1346. Visual meteorological conditions prevailed, and no flight plan was filed.
According to the pilot, after takeoff he proceeded west to climb above Fresno Yosemite International Airport (FAT) and verified his transponder with Fresno Approach. He then headed west/southwest. About 15 to 20 minutes later, during a descent to remain below FAT Class C airspace, the pilot noticed the airplane batteries (located near his right foot) becoming hot. He switched the engine monitor display to check electrical values, observing a voltage of 15.5 volts and current just above 30 amperes. The engine then suddenly lost all power, with the propeller continuing to windmill.
The pilot made brief, unsuccessful attempts to restore power before focusing on landing. He determined the nearest airport was Selma Airport (0Q4), about 10 miles away, and began gliding toward it while communicating with Fresno Approach. At approximately 1,000 ft altitude, he realized he could not reach 0Q4 and selected a road as a landing site. After maneuvering to avoid an oncoming truck and underflying powerlines, the airplane touched down in a vineyard, nosed over, and came to rest inverted. The pilot escaped by breaking the canopy. Fuel leaked but no fire occurred. FAA inspectors examined the wreckage at the site before transport for further investigation.
Pilot Information
The pilot held commercial, airline transport, and flight instructor certificates with single- and multi-engine land and instrument ratings. He reported 2,700 total flight hours, including 300 hours in the accident airplane make and model. His most recent flight review and first-class medical certificate were both completed in October 2017.
Aircraft Information
The airplane was constructed in 2000 and purchased by the accident pilot in February 2013. At purchase, it was equipped with a Lycoming O-360 series engine and a Hartzell two-blade constant-speed propeller. The pilot later undertook significant modifications, replacing the original carburetor and magneto ignition with an aftermarket electronic fuel injection and ignition system (SDS brand), and updating the avionics with a Garmin G3X system. Two EARTHX lithium-ion batteries were installed. None of these components met FAA technical standard orders, nor were they required to. About five weeks before the accident, the pilot completed the modifications and conducted ground runs totaling 1.5 to 2 hours, plus two brief test flights. The accident flight was the third flight with the new systems.
Electrical System Examination
Post-accident examination revealed that the alternator ground cable had a loose swage at the terminal, with black residue consistent with arcing and fretting, indicating the connection had been compromised for an extended period. The alternator's cockpit circuit breaker (rated 60 amperes) was not tripped; its design prevented manual disconnection by the pilot. The two lithium-ion batteries were equipped with over-voltage protection circuitry, but the pilot reported that indicator LEDs did not illuminate, suggesting the protection did not activate. The airplane was equipped with a FlyEFII bus manager, which included an emergency power switch; the pilot reported activating it without restoring engine power.
Engine Performance Data
Data downloaded from the G3X system recorded multiple parameters, including voltage and current. On the accident flight, nominal voltage was about 13.8V, then rose to a peak of 16.3V approximately three minutes before the engine stopped. Current also rose from a stable 30A to 33A. The engine ceased operation at 1411:02, with current instantaneously dropping to 0A. No anomalies were noted in other engine parameters prior to the power loss.
Additional Factors
No checklists for engine failure or electrical emergencies were found in the airplane. The pilot attempted to restore power by selecting each engine control unit independently and using the emergency power switch, all without success. The investigation did not identify a single point of failure, though the loose alternator ground cable and resulting voltage surge were consistent with the power interruption that disabled the electronic ignition and fuel injection systems.