Aviation Accident Summaries

Aviation Accident Summary ANC15LA004

Nenana, AK, USA

Aircraft #1

N6465V

HELIO H 295

Analysis

The pilot stated that, just after takeoff, as the airplane climbed through about 35 ft above ground level, the engine began to gradually lose power. Unable to restore power, the pilot made a forced landing in an area of densely populated trees. During the forced landing, the airplane sustained substantial damage to the wings and fuselage. A postaccident examination revealed no evidence of any preimpact mechanical anomalies with the airplane's engine or systems. The engine was subsequently started and then operated while still mounted on the airplane's airframe. No anomalies were observed during its operation, and the engine produced full factory-specified rpm.

Factual Information

On November 14, 2014, about 1645 Alaska standard time, a wheel/ski-equipped Helio Courier H-295 airplane, N6465V, sustained substantial damage during a forced landing, following a partial loss of engine power after takeoff from a remote unimproved airstrip near Nenana, Alaska. The airplane was operated by Wright Air Service, Fairbanks, Alaska, as a visual flight rules (VFR) on-demand charter flight under the provisions of 14 Code of Federal Regulations (CFR) Part 135.The certificated airline transport pilot and two passengers were not injured. Visual meteorological conditions prevailed, and a VFR flight plan had been filed. The flight departed Old Minto, Alaska, at about 1640 destined for Fairbanks, Alaska. During an interview with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on November 17, the pilot stated that just after takeoff, as the airplane climbed through approximately 35 feet above ground level, the engine began to gradually lose power. Unable to restore engine power, he made a forced landing in an area of densely populated black spruce trees. During the forced landing the airplane sustained substantial damage to wings and fuselage. The airplane was equipped with a Lycoming GO-480-G1D6 engine, the pressure carburetor was replaced with a Bendix fuel injection system, under the Federal Aviation Administration (FAA) field approval process. On November 21, 2014, an engine examination was performed by the NTSB IIC, two other NTSB investigators, along with two FAA air safety inspectors from the Fairbanks Flight Standards District Office (FSDO). Also present was a party representative from Wright Air Service. No anomalies, contamination, or evidence of malfunction was found in any of the engine accessories. The cylinders, pistons, valve train, crankshaft, and other internal components were all without evidence of anomaly or malfunction. At the direction of the NTSB IIC, the engine fuel servo was removed and tested for proper operation. During fuel flow testing, the fuel servo produced a correct fuel mixture at a full-power setting. On December 23, the engine, while still mounted on the accident airplane's airframe, was operated under the direction of the IIC, along with the rest of the investigative team. The engine ran without any observed anomalies, and produced full factory specified rpm. A drop of about 25 rpm was noted for the left and right magnetos. A series of power adjustments from idle to full power were conducted with no hesitation in engine operation noted. The closest weather reporting facility was Nenana Airport, about 23 miles south of the accident site. At 1653, a weather observation from Nenana Airport was reporting, in part: wind from 080 degrees, at 7 knots; visibility, 10 statute miles; clouds and sky condition, clear; temperature, 27 degrees F; dew point 14 degrees F; altimeter, 30.16 inHG

Probable Cause and Findings

The partial loss of engine power for reasons that could not be determined because postaccident examination of the engine revealed no evidence of any preimpact mechanical anomalies.

 

Source: NTSB Aviation Accident Database

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