N508AH

HISTORY OF FLIGHTOn January 7, 2016, about 1540 central standard time, an experimental amateur-built Eros 1600 airplane, N508AH, collided with terrain following a total loss of engine power near Lebanon, Tennessee. The private pilot was fatally injured, and the airplane was substantially damaged. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed in the area, and no flight plan was filed for the local flight, which departed from Lebanon Municipal Airport (M54).

GPS data indicated that the airplane departed M54 at 1515 and conducted an approximate 20-minute local flight. The airplane then returned to the airport, landed, and initiated a second takeoff.

One witness, who was a pilot, stated the airplane conducted a normal takeoff, then began a right turn at low altitude. The airplane then "abruptly" turned left about 100 ft above ground level (agl) "as if it was trying to return to the airport." The airplane subsequently rotated "sharply" to the left and descended to ground contact as it disappeared from his view. Several witnesses reported hearing the airplane "circle" at low altitude, followed by a loss of engine power.

A friend of the pilot stated that the pilot had been performing maintenance on the engine because it was "intermittently missing." The pilot had installed a new ignition coil onto the engine, and on the day of the accident, the pilot reinstalled the engine onto the airplane. The accident flight was a test flight to determine if the engine problem had been resolved. PERSONNEL INFORMATIONAccording to Federal Aviation Administration (FAA) records, the pilot held a private pilot certificate with a rating for airplane single-engine land. In addition, the pilot held a repairman experimental aircraft builder certificate that was issued on May 15, 2014. He was issued a third-class FAA medical certificate on August 24, 2006, with no limitations. The pilot's logbooks indicated that he had about 259 total hours of flight time, of which 8.9 hours were in the accident airplane. His most recent flight review was completed on May 27, 2014. AIRCRAFT INFORMATIONAccording to FAA records, the experimental amateur-built airplane was owned by the pilot and issued an airworthiness certificate on May 15, 2014. It was equipped with a two-cylinder Rotax 532, 64-horsepower (hp) engine, which was installed on October 7, 2015. According to maintenance logbooks, the airplane had a total time of about 14 hours. The airplane's most recent condition inspection was completed by the pilot on October 7, 2015, at a total time of 1.6 hours. A white board in the pilot's hangar noted that he serviced the engine with a fuel/oil ratio of 40:1. According to the pilot's son, the engine was previously installed on a snowmobile.

According to the airplane operating handbook, the airplane was designed to be equipped with a 41-hp, Rotax 447 engine. With this engine installed, the airplane's flaps-up stall speed was 34 mph, and its flaps-extended stall speed was 29 mph. The emergency procedures section stated,

"About the only failure you can have in planes as simple as the MAX is an engine failure, and since you are flying an uncertified engine, that occurrence is not too unlikely. Unless the failure is a result of inadvertently switching off the magneto, a restart is unlikely, therefore, begin planning immediately for a forced landing.

Establish a glide at minimum airspeed at least 45 [calibrated airspeed]. If you are climbing, immediately lower the nose to the glide attitude. Pick a landing spot (you should already have one in mind). The MAX glides at about 6/1 angle, but any turbulence will strongly effect this. Also, keep in mind wind shear (gradient) as you approach the ground, and keep your airspeed up in a strong wind.

Perform a normal power off landing (you should have practiced this many times). Minimum airspeed as you begin your flare should be approximately 40 mph. Any lower airspeed and you may not have enough energy to arrest your sink rate." METEOROLOGICAL INFORMATIONThe 1553 recorded weather observation at Smyrna Airport (MQY), Smyrna, Tennessee, located about 14 nautical miles southwest of the accident location, included wind from 120° at 4 knots, visibility 10 statute miles, broken cloud layers at 3,500 ft agl and 4,400 ft agl, temperature 13°C, dew point 8°C, and an altimeter setting of 30.02 inches of mercury. AIRPORT INFORMATIONAccording to FAA records, the experimental amateur-built airplane was owned by the pilot and issued an airworthiness certificate on May 15, 2014. It was equipped with a two-cylinder Rotax 532, 64-horsepower (hp) engine, which was installed on October 7, 2015. According to maintenance logbooks, the airplane had a total time of about 14 hours. The airplane's most recent condition inspection was completed by the pilot on October 7, 2015, at a total time of 1.6 hours. A white board in the pilot's hangar noted that he serviced the engine with a fuel/oil ratio of 40:1. According to the pilot's son, the engine was previously installed on a snowmobile.

According to the airplane operating handbook, the airplane was designed to be equipped with a 41-hp, Rotax 447 engine. With this engine installed, the airplane's flaps-up stall speed was 34 mph, and its flaps-extended stall speed was 29 mph. The emergency procedures section stated,

"About the only failure you can have in planes as simple as the MAX is an engine failure, and since you are flying an uncertified engine, that occurrence is not too unlikely. Unless the failure is a result of inadvertently switching off the magneto, a restart is unlikely, therefore, begin planning immediately for a forced landing.

Establish a glide at minimum airspeed at least 45 [calibrated airspeed]. If you are climbing, immediately lower the nose to the glide attitude. Pick a landing spot (you should already have one in mind). The MAX glides at about 6/1 angle, but any turbulence will strongly effect this. Also, keep in mind wind shear (gradient) as you approach the ground, and keep your airspeed up in a strong wind.

Perform a normal power off landing (you should have practiced this many times). Minimum airspeed as you begin your flare should be approximately 40 mph. Any lower airspeed and you may not have enough energy to arrest your sink rate." WRECKAGE AND IMPACT INFORMATIONThe airplane impacted terrain and came to rest inverted on a westerly heading, next to a residence located about 850 ft from the departure end of runway 04. All components of the airplane were located near the wreckage. Flight control continuity was established from the flight controls in the cockpit to all flight control surfaces.

The propeller was rotated by hand and engine continuity was confirmed from the propeller flange to the back of the engine. The two spark plugs were removed; the aft cylinder spark plug was dark grey in color and exhibited normal wear. The front spark plug was white in color. Thumb compression was obtained on the aft cylinder, however, no compression was observed on the front cylinder.

The top section of the engine case was removed to facilitate further examination, and a hole was found in the front cylinder piston. The hole was approximately 1 centimeter in diameter located in the center of the piston. The aft cylinder exhibited carbon deposits and oil residue on the top of the cylinder. The connecting rod bearings were loose in both the front and aft cylinders. The exhaust y-pipe was removed and carbon deposits were noted in the aft exhaust pipe. The front cylinder exhaust gas temperature probe was white in color, and the aft cylinder exhaust gas temperature probe was grey in color.

Each of the engine's two carburetors were impact separated but remained attached to the engine through cables. Disassembly of both carburetors revealed that the respective jet needles were on the third clip from the top and were under the white retaining cup, and both the main jet and the pilot jet were free of debris. The front and aft carburetor rubber adaptors contained cracks and evidence consistent with material degradation. The front carburetor adaptor was also partially fractured in several places around the boot.

The rotary valve plate cover was removed to examine the timing of the rotary valve. It was timed so that the intake port on the cylinder was fully open when the respective piston was at the top dead center position.

The ignition coil remained attached to the engine; however, a wire was separated. The coil was rigged and was tested. Ignition continuity was confirmed from the flywheel to the spark plugs during propeller rotation. ADDITIONAL INFORMATIONEngine Operator's Manual

According to the engine operator's manual, the proper mixing ratio of fuel to oil was 50:1. The manual stated, "Too much oil will cause carbon deposits on the spark plug, on the piston, in the cylinder ports and in the muffler and will cause problems." The manual stated that white spark plug electrodes indicated a low heat range (hot plug) or excessively lean carburetor calibration.

Engine Repair Manual

The engine repair manual stated that the carburetor must be checked and adjusted after every 25 hours of operation. The carburetor adaptor should be checked thoroughly for "tightness, cracks, cuts or other physical damage." The manual stated that, at "the slightest signs of damage" the carburetor adaptor should be exchanged, "Otherwise pressure conditions in carburetor will be changed, additional air will be taken in, possibly leading to engine damage."

Pilot's Handbook of Aeronautical Knowledge – Aircraft Systems

According to the Pilot's Handbook of Aeronautical Knowledge,

"Detonation is an uncontrolled, explosive ignition of the fuel/air mixture within the cylinder's combustion chamber. It causes excessive temperatures and pressures which, if not corrected, can quickly lead to failure of the pisto...