IN-FLIGHT SMOKE ? THE INCIDENT
On February 8, 2017, the incident aircraft (an RV-8A purchased by the pilot from its original builder), departed Sedona Airport (KSEZ) on a return flight to Phoenix Deer Valley Airport (KDVT) with two pilots on board. Total time on the aircraft/engine was 880 hours since new. The pilot had owned the RV-8A for over 6 years and flown the aircraft over 320 hours without incident.
At the time of this incident, the aircraft had flown a total 6 flights and 2.7 hours since undergoing an instrument panel upgrade. A Dynon Skyview HDX system was installed in place of the standard “Six Pack” of instruments and Van’s standard engine gages. In addition to the Dynon HDX system, to save weight, an EarthX ETX-680 Lithium-Iron-Phosphate (LiFePO4), battery was installed in place of the standard lead-acid battery. Both pilot (front cockpit) and copilot (rear cockpit) were experienced, current ATP pilots.
Approximately 16 minutes after takeoff, while accomplishing an in-flight compass calibration test, consisting of 360-degree turns at 7,500’ MSL (3,000’ AGL), both pilots noted a brief acrid smell (for about 2 seconds). Engine/electrical indications were reviewed, and no anomalies were noted. Specifically, volt and amp readings were observed to be within the normal range – 14.3 volts and 14 amps.
Approximately 18 minutes after takeoff a climb was initiated from 7500' to 9500' MSL along with a turn to the southwest toward less challenging terrain; just in case an emergency landing was required.
Approximately 1 minute later (19 minutes after takeoff), the voltage and amperage indications started to increase rapidly and fluctuate (voltage fluctuated between 19 and 25 volts, and amperage fluctuated between 40 and 44 amps). In addition, the electrically-powered fuel quantity indicator failed. Because the pilot thought he was experiencing a component electrical problem behind the panel, all electrical component switches were turned off; however, the Alternator/Battery Master Switch was inadvertently left on. The pilot acknowledges that he should have confirmed that the master switch was turned off when he first observed the high voltage and amperage fluctuations, however, he was focused on a "behind-the-panel" component failure; not an aircraft electrical power system failure. (Note: the alternator's main 35-amp breaker had not tripped).
Approximately 4 minutes later, while maneuvering the aircraft to an area where an off-field landing could be attempted, a strong “solvent type” odor was detected, and an immediate descent was initiated. Several seconds after initiating the descent, smoke entered the cockpit from behind and below the instrument panel. The source of the smoke confirmed to the pilot that he probably did have a behind-the-panel component failure. With the appearance of the smoke, a high-speed emergency descent was initiated via a Split-S maneuver. The copilot suggested opening the canopy, however, lacking any knowledge as to the ability to maintain structural integrity of the aircraft when opening the canopy inflight, the pilot initially elected not to open it. As the smoke intensified, visibility in the front cockpit was reduced to near zero, and it became very difficult for the pilot to breathe. The copilot in the rear cockpit had better, but limited, visibility and some fresh air from the rear air-vent sourced from the underside of the right wing. Having no other option, the pilot transferred aircraft control to the copilot, and the decision was made to open the canopy.
The pilot then attempted to open the canopy with one hand, but was initially unsuccessful. The canopy would not easily open as it normally does during ground operations. Using both hands on the canopy handle and much greater force than normal, the canopy slid aft approximately two feet. As fresh air flowed around the windshield, most of the smoke vented out of the cockpit via the canopy bottom skirt. Although smoke was still entering the lower portion of the cockpit, the pilot had recovered visibility and the ability to breathe. The pilot did not detect any heat or fire, and the copilot found that he could easily hold the canopy in the partially open position. Therefore, aircraft control was transferred back to the pilot while the copilot held the canopy to prevent it from sliding to the rear stop.
The pilot originally intended to land on a nearby stretch of interstate highway located approximately 5 miles ahead; however, the copilot observed a street pattern at 3 o'clock and less than a mile. The pilot circled to slow, and successfully landed on an uphill residential street, without any related damage to the RV-8A. The airplane was stopped, and the engine was shut-down approximately 27 minutes after takeoff and 3-to-4 minutes after the emergency descent was initiated. The descent covered approximately 5500 feet, and the descent rate averaged approximately 1600 feet per minute with peak descent in the neighborhood of 3000 feet per minute. TAS (true airspeed) during the emergency decent was recorded as high as 194 knots; with the canopy open.
After landing, smoke continued to enter the cockpit from behind the instrument panel. Halon was discharged underneath the panel, and the crew exited the aircraft. The forward baggage compartment was opened, the instrument (rear-access) panel was removed, and halon applied to the back of the instrument panel. At this point it was discovered that the source of the smoke was from the battery compartment located directly below the front baggage compartment, on the right side of the aircraft. This area was repurposed by the original builder as a battery compartment, complete with an access panel on top. The battery compartment access panel was removed, and the remaining halon applied directly to the battery. After the halon bottle was depleted, dirt from the roadside was used to completely extinguish the smoldering battery.
Note: No radio transmissions were made during this incident, since the radios were turned off to protect them.
The pilot was treated for smoke inhalation at a local hospital and has fully recovered. The pilot did not suffer from any burns or additional physical harm. The copilot did not suffer any physical harm. The FAA and NTSB were notified and classified this mishap as an unreported “incident”, since there were no serious injuries or structural damage to this experimental aircraft. The RV-8A was dismantled and transported to a repair facility. Subsequently, the RV-8A has successfully returned to flight with no further problems.
Last edited by Bill Palmer : 10-18-2017 at 02:13 AM.