Accident Overview
On April 8, 2014, at about 1557 Alaska daylight time, a Cessna 208B Caravan, registration N126AR, was destroyed after impacting terrain about 22 miles southeast of Kwethluk, Alaska. The airplane was operated by Hageland Aviation Services, Inc., doing business as Ravn Connect, as a visual flight rules training flight under 14 CFR Part 91. Both crewmembers—a check airman and a newly hired second-in-command (SIC) pilot—were fatally injured. Day visual meteorological conditions prevailed, and company flight-following procedures were in effect. The local training flight departed Bethel Airport at 1535.
Personnel Information
The check airman, age 42, held an airline transport pilot certificate with multiengine land and commercial single-engine land ratings. His most recent FAA first-class medical was issued February 25, 2014, without limitations. He had 14,417 total flight hours, with 5,895 hours in the accident airplane type. His personal logbooks were not located.
The SIC, age 46, held a commercial pilot certificate with single-engine land, multiengine land, and instrument ratings, plus flight and ground instructor certificates. His most recent second-class medical (May 30, 2013) required corrective lenses for near and distant vision. He reported 593 total flight hours, with none in the accident airplane type. His personal logbooks were not located.
Aircraft Information
The accident airplane, a 2002 Cessna 208B Caravan (serial 208B1004), had accumulated 11,206 total flight hours. It was maintained under an approved inspection program; the most recent airframe and engine inspection was completed March 13, 2014. The airplane was equipped with a Pratt & Whitney PT6A-114A turbine engine (675 shaft horsepower), overhauled 4,286 hours before the accident.
The aircraft had a Bendix/King KFC-150 Autopilot System with three-axis autopilot and electric pitch trim. The trim system was designed to withstand any single in-flight malfunction, with trim faults annunciated visually and aurally. Emergency procedures for an electric trim malfunction specified pressing and holding the A/P DISC/TRIM INTER switch, pulling the ELEV TRIM circuit breaker, and retrimming manually. The supplement noted that up to 45 pounds of force on the control wheel might be needed to hold the aircraft level after disconnecting the autopilot.
Meteorological Information
The nearest reporting station, Bethel Airport (27 miles northeast), reported at 1553: wind from 020 degrees true at 8 knots, visibility 10 statute miles, clear sky, temperature 19°F, dew point 3°F, altimeter 28.87 inHg.
Communications and Flight Recorders
No communications were made with the accident airplane at the time of the accident. The airplane was not equipped with a cockpit voice recorder or flight data recorder.
ADS-B Tracking
The airplane was equipped with Automatic Dependent Surveillance-Broadcast (ADS-B). Data from the Anchorage ARTCC showed that after departure, the airplane flew northeast and conducted maneuvers consistent with training. About 21 minutes into the flight, at about 3,400 ft mean sea level (msl), a slight altitude fluctuation occurred, followed by an initial upset. The airplane then descended rapidly and steeply until ground impact.
Wreckage and Impact
The accident site was on a land thumb in a bend of the Kwethluk River at about 75 ft msl. Ground scars extended from frozen tundra through heavy willows, where the airplane rested upright supported by toppled willow trees. An extensive postcrash fire consumed most of the fuselage, with worst damage near the forward fuselage and cockpit.
Initial impact crater and wreckage path were oriented at about 128 degrees magnetic. Belly pod fragments were sprayed forward. The farthest piece, a main landing gear tire, was about 330 ft ahead of the main wreckage. Initial ground impact scars were about 200 ft west of the main wreckage. Top willow strikes suggested an approximate 33-degree nose-down attitude at impact. A mark in the tundra matching the left main landing gear was noted.
The propeller separated; two blades were loose in the hub, one blade fractured inside the hub. The separated blade was missing about 12 inches of its outboard section. Both wings separated from the fuselage and sustained severe impact and thermal damage. The engine separated and was crushed, with fragmented accessories.
Medical and Pathological Information
Postmortem examinations attributed the cause of death for both pilots to multiple blunt force injuries. Toxicology for the check airman was negative for carbon monoxide, drugs, and ethanol. For the SIC, testing was negative for carbon monoxide and drugs; ethanol was detected in muscle (14 mg/dL) and liver (10 mg/dL), but CAMI could not determine if it was from ingestion or postmortem sources.
Test and Research
An NTSB Airworthiness Group examined the wreckage. The flap jackscrew extension (6.5 inches) indicated flaps were up at impact. Right elevator trim tab actuator extension was 2.2 inches (about 8 degrees tab up); left elevator trim tab actuator extension was 2.4 inches (about 14.5 degrees tab up). All examined fractures had a dull, grainy appearance consistent with overload failure. No preexisting corrosion or cracking, and no preimpact fire or bird impact evidence was found.
An aircraft performance study using ADS-B data and a Cessna 208B simulator indicated normal flight until 1556:30, then a steep descent with maximum descent rate about 16,000 ft/min. Elapsed time from initial upset to impact was about 22 seconds. At the last ADS-B plot, simulated calibrated airspeed was about 256 knots, bank angle about 2 degrees right, and pitch angle changed to -34 degrees just before impact (maximum -40 degrees). The simulation indicated that during the initial upset, left bank angle momentarily exceeded 60 degrees.
Simulations of elevator position, trim tab position, and control column force were run for normal and runaway pitch trim scenarios. In the normal scenario, control column push force increased to about 130 pounds at impact. In the runaway pitch trim scenario, control column pull force increased to about 800 pounds at impact.
Organizational Information
Hageland Aviation Services is a Part 135 air carrier with on-demand and commuter operations specifications, authorized to do business as "Hageland Aviation Services, Inc." or "Ravn Connect." Company headquarters are in Anchorage, Alaska, with the president/chief pilot based there and the director of operations and director of maintenance in Palmer.
Additional Information
Review of previous training flights by the check airman showed a consistent pattern: standard maneuvers (steep turns, slow flight, stalls) were followed by a simulated emergency and descent to 100-200 ft above ground level over a river, after which the trainee would "fly the river." Company personnel stated this maneuver was used to teach coordination. The accident flight followed this routine, with the accident sequence occurring during the simulated emergency and descent phase.