ERA17LA016

The private pilot of the experimental amateur-built airplane reported that the airplane had been flying uneventfully for about 40 minutes when it lurched and the engine experienced a partial, then total, loss of power. He placed the carburetor heat control to the high setting and established the airplane's best glide airspeed. The pilot then attempted to restart the engine. Although it initially started, the engine would not develop power and shut down after a few seconds. Two additional restart attempts were also unsuccessful, and the pilot subsequently performed a forced landing into trees. Postaccident examinations of the airframe and engine, which included an engine test run, did not reveal evidence of preimpact mechanical failures or malfunctions, and there was sufficient fuel onboard at the time of the accident. Although the weather conditions at the time of the accident were conducive to serious carburetor icing at glide power, the engine was operating at a cruise power setting at the time of the power loss and the pilot applied carburetor heat at the first indication of a problem, which did not restore engine power. Therefore, the investigation was unable to determine the reason for the total loss of engine power.

On October 15, 2016, about 1540 eastern daylight time, an experimental amateur-built Zenith CH701, N3701M, was substantially damaged during a forced landing near Albrightsville, Pennsylvania. The private pilot sustained serious injuries and one passenger had minor injuries. The airplane was operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Day, visual meteorological conditions prevailed at the time, and no flight plan was filed. The flight originated from Benton Airport (PA40), Benton, Pennsylvania about 1455, and was destined for Pegasus Air Park (50PA), Stroudsburg, Pennsylvania.The pilot reported that he was about 8 minutes from landing and preparing to descend from 3,000 feet mean sea level (msl) to 1,400 feet msl. The airplane made a "slight lurch" and the engine rpm dropped, followed by a complete loss of power. He placed the carburetor heat to the high setting and established best glide airspeed of 50 to 55 mph. The fuel selector valve was checked, and an engine restart was attempted. The engine initially started; however, it would not develop power and shut down after a few seconds. A second restart was attempted with the same results. A third restart was attempted, and the engine would turn over but not start. The pilot slowed the airplane as much as possible and prepared for a forced landing into trees. The airplane settled into the trees and came to a stop on its left side. The pilot and passenger exited the airplane and were met by first responders. An inspector with the Federal Aviation Administration (FAA) responded to the accident site and examined the wreckage. Structural damage to the wings, fuselage, and empennage was confirmed. An examination of the engine and fuel system did not reveal evidence of a mechanical malfunction, fuel blockage, or fuel contamination. The pilot reported that the airplane's fuel tanks were topped off earlier that day with about 20 gallons of fuel, and there were about 15 gallons on board the airplane when the accident flight began. The airplane was equipped with a Dynon FlightDEK D-180 electronic flight information system (EFIS) and a Garmin GPSMap196, both of which captured the accident flight. According to recovered data, the flight began at 1454 and terminated at 1539. A review of the Dynon engine monitor data showed that engine parameters were normal and stabilized until a decrease in rpm, oil pressure, cylinder head temperature, oil temperature, and exhaust gas temperature simultaneously occurred about 1535:30. The EFIS also confirmed there was fuel in both wing tanks when the loss of engine power occurred. The airplane was a high wing, tricycle landing gear, short takeoff and landing (STOL) design. It was equipped with a Jabiru 3300A engine and a Sensenich fixed pitch propeller. The total aircraft time at the time of the accident was about 60 hours. The engine was sent to the Jabiru USA facility at Shelbyville, Tennessee for furtherexamination and a test run. There was some impact damage to the engine. The engine mounts were bent and the propeller flange had a very slight deformation. The carburetor was filled with oil due to the engine being shipped inverted. The carburetor was removed and the oil was cleaned out. There was no water and no contaminants inside the carburetor other than the engine oil. The carburetor was then reinstalled. The No. 3 cylinder rocker cover was dented from impact and was replaced with a spare for the run. Dried blue residue with the appearance of fuel staining was observed on the outside of the carburetor bowl; however, the carburetor did not leak. The engine started on the first attempt after engaging the starter for about 2 seconds. The engine initially emitted oily smoke (a light blue/gray color) which cleared after about 8 seconds of operation. The engine was run for about 6 minutes and 30 seconds with no anomalies noted. The engine was run to a peak rpm of 2,670 and oil temperature and pressure were within the green bands. The run was subsequently terminated by the investigation team. Pocono Mountains Municipal Airport (MPO) was located about 12 miles northeast of the accident site. At 1553, about 14 minutes after the accident, the temperature and dew point were 57° and 36° F, respectively. According to the carburetor icing probability chart in FAA Special Airworthiness Information Bulletin CE-09-35, dated June 30, 2009, the temperature/dew point conditions were conducive to serious icing at glide power.