N4494ABeech 58 · 1970

On December 7, 2017, about 2100 Atlantic standard time, a Beech BE58, N4494A, was destroyed when it impacted terrain while returning to the runway shortly after takeoff from Henry E. Rohlsen Airport (TISX), Christiansted, St. Croix, United States Virgin Islands (USVI). The private pilot and four passengers were fatally injured. The airplane was privately owned and operated under the provisions of Title 14 Code of Federal Regulations Part 91. Night visual meteorological conditions prevailed and no flight plan was filed for the personal flight, which was destined for Cyril E. King Airport (TIST), Charlotte Amalie, St. Thomas, USVI.

A review of air traffic control audio information revealed that the airplane departed runway 10. Shortly thereafter, the pilot informed the controller that the engines were "not running right" and requested to return to the airport. The controller instructed the pilot to fly north and cleared the airplane to land on runway 10. There were no further communications from the pilot.

Before departing on the flight, the pilot called a flight instructor/mechanic because the left engine would not start and the red alternator light was on. The flight instructor told the pilot to wait until the next day to fly the airplane. The day after the accident, an oil stain was found on the ramp where the airplane had been parked the day before.

Review of Federal Aviation Administration (FAA) airman records revealed that the pilot held a private pilot certificate with a rating for airplane single-engine land. He did not possess a multiengine rating. The pilot's most recent FAA first-class airman medical certificate was issued on August 1, 2016, with the limitation, "must have available glasses for near vision." At that time, he reported 765 total hours of flight experience.

The pilot's logbook was not located.

The six-seat, low-wing, retractable-gear equipped airplane was manufactured in 1970. It was powered by two Continental IO-520, 285-horsepower engines, each driving a Hartzell three-bladed, constant-speed, full-feathering propeller. The maintenance logbooks were not located.

At 2053, the weather conditions reported at TISX included wind from 070° at 8 knots, 10 statute miles visibility, scattered clouds at 6,000 ft, temperature 25°C, dew point 21°C, and an altimeter setting of 30.01 inches of mercury.

The six-seat, low-wing, retractable-gear equipped airplane was manufactured in 1970. It was powered by two Continental IO-520, 285-horsepower engines, each driving a Hartzell three-bladed, constant-speed, full-feathering propeller. The maintenance logbooks were not located.

The airplane was destroyed by impact forces and consumed by a postcrash fire. The wreckage was located on flat terrain about 500 ft from the displaced threshold of runway 10 and about 30 ft right of the extended runway centerline. All major portions of the wreckage were located at the accident site and were found within about 30 ft of the main wreckage.

All flight control surfaces were accounted for at the accident site and flight control continuity was confirmed from the cockpit to the respective control inputs. The landing gear and wing flaps were in the retracted position. The rudder and ailerons were largely consumed by fire, and their respective cables were attached and traced forward to the cockpit controls.

The right wing was folded over the cockpit; the right engine was attached and inverted. The right engine cylinders were inspected with a lighted borescope; all intake and exhaust valves were intact and the cylinders appeared normal. The spark plugs showed normal wear. The fuel manifold was thermally damaged and the fuel screen was free of contaminants. The alternator, oil filter, and oil cooler were thermally damaged.

The right propeller was separated from the engine just aft of the crankshaft propeller flange. The propeller was located about 30 ft from the main wreckage with one blade buried in the ground. The second blade was partially buried, and the third blade exhibited minimal damage.

The left wing remained attached to the fuselage and sustained extensive fire damage. The left engine was separated from its mounts but remained in the nacelle. A visual inspection noted that connecting rod Nos. 4, 5, and 6 were broken. The left engine cylinders were inspected with a lighted borescope; all intake and exhaust valves were intact. The spark plugs showed normal wear.

The left propeller was separated from the engine but remained attached to the engine crankshaft propeller flange. The propeller was located about 20 ft left of the right propeller. The blades appeared to be in the feathered position; one of the three blades was buried in the ground.

The left engine was recovered to a secure storage area for more detailed examination.

A visual inspection noted a hole, on the top forward portion of the crankcase, above cylinder Nos. 1, 2, and 6. The engine was then dissembled, and heat distress was noted on some of the cylinders. All the pistons were removed from the cylinders. The No. 2 piston crown exhibited damage consistent with severe detonation. The side of the piston was melted by excessive detonation and a hole was present near the wiper ring. The inside of the No. 2 cylinder displayed excessive deposits from the top of the piston as a result of the detonation.

The left and right exhaust manifolds remained attached to the cylinder head exhaust ports but were impact damaged. The oil pump displayed external thermal damage. When disassembled, the gears and pump body exhibited light scarring consistent with hard particle passage.

The magnetos were separated from the engine. When placed on a test bench, both magnetos sparked and proper firing order was confirmed. The spark plugs were normal-to-worn-out when compared to a Champion Check-A-Plug chart.

The fuel nozzles were unobstructed. The fuel manifold was removed and opened for examination. The diaphragm was intact. Small particles of white debris were found under the screen. The manifold was sent to the NTSB Materials Laboratory, Washington, DC for examination. The material chemical composition was examined using energy dispersive x-ray spectroscopy. The material was identified as aluminum oxide. Neither the airframe or engine manufacturer's representatives were aware of any system component or test where this debris would have been introduced.

For additional information regarding the examination of the fuel manifold, see the NTSB Materials Laboratory Factual Report located in the public docket for this investigation.

FAA H-8083-25B, the "Pilot's Handbook of Aeronautical Knowledge" explains:

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 piston, cylinder, or valves. In less severe cases, detonation causes engine overheating, roughness, or loss of power…

Engine Inoperative Approach and Landing

The approach and landing with one engine inoperative is essentially the same as a two-engine approach and landing. The traffic pattern should be flown at similar altitudes, airspeeds, and key positions as a two- engine approach. The differences are the reduced power available and the fact that the remaining thrust is asymmetrical….

FAA P-8740-66, "Flying Light Twins Safety," stated in part:

The major difference between flying a light twin and a single-engine airplane is knowing how to manage the flight in one engine loses power. Safe flight with one engine inoperative (OEI) requires an understanding of the basic aerodynamics involved as well as proficiency in single-engine flight.

The Virgin Islands of the United States Office of the Medical Examiner, St. Croix, USVI, performed the autopsy of the pilot. The cause of death was multiple blunt force injuries.

The FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicology testing on specimens from the pilot. Ethanol was detected in the urine and blood, consistent with post-mortem alcohol production. No medications or other substances were present.