Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Engineer; Flight Crew Multiengine
Flight Crew Last 90 Days 107; Flight Crew Total 11058; Flight Crew Type 322
Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Flight Crew Landed in Emergency Condition
Aircraft
While flying a level 360-degree turn (for a compass calibration test); we briefly noticed (for a few seconds); an acrid odor that quickly stopped. We terminated the test and headed southwest and climbed from approximately 7500 MSL to 8500 MSL. Examining the instruments; I noted that the amperage and the battery voltage were fluctuating (within the green band). [A few minutes later]; we began to smell a 'solvent type' odor. The ammeter reading increased to 44 amps; the battery volts increased to 19.8 volts; and the electrically powered fuel indicator failed. We began an immediate descent; and all electrical switches were turned off. A few moments later; we began getting smoke in the cockpit from behind the instrument panel; and we began a high-speed emergency descent. This was followed by a dramatic increase in smoke density; making it difficult to breathe; and reducing visibility in the front cockpit to near zero. We opened the canopy in order to evacuate the smoke; and landed on the nearest available road. After landing; the smoke continued from behind the instrument panel; [and] I applied Halon to the area. After exiting the aircraft; we determined the smoke was coming from the battery compartment. We applied the remainder of the Halon; and then poured dirt into the battery compartment to extinguish the fire.The time from the initial odor/high electrical reading; until landing; was approximately 4 to 7 minutes. Battery Type: EarthX ETX 680 (approx 2.7 hrs of use). Alternator/Voltage Regulator: BoschEFIS/Engine Instrumentation: Dynon Skyview HDX
RV-8 pilot reported landing on a small road after the cockpit filled with smoke from an electrical system problem.