Aviation Accident Summaries

Aviation Accident Summary CEN13LA401

Chesaning, MI, USA

Aircraft #1

UNREG

JDT 1600R

Analysis

Several witnesses reported seeing the airplane heading north, turning, and then losing control. One witness stated that engine was "inordinately loud" and that the airplane appeared to enter a "nose dive." Another witness reported that the engine sounded like it was "cutting out" as the airplane spun to the ground. The pilot had been issued a student pilot certificate about 7 years before the accident; however, no pilot flight logbooks were recovered, so the pilot's level of training could not be determined. A postaccident examination of the airframe and flight control system revealed no anomalies. An examination of the engine showed that all of the teeth of one of the two gears in the propeller reduction gearbox were broken off. Additionally, the ball retaining cage on one of the ball bearings that supported the propeller shaft had failed, and several of the balls were missing from the bearing. A sludgelike substance resembling old oil was found in the gear reduction case, and no liquid oil was found, which is indicative of inadequate maintenance. No airplane maintenance records were found. Based on the available evidence, it is likely that the bearing and gear in the propeller reduction gearbox failed as a result of inadequate maintenance (lack of lubrication), which resulted in a loss of propeller thrust and reduced the airplane's airspeed. The pilot did not obtain adequate airspeed (by lowering the nose), which led to the exceedance of the airplane's critical angle-of-attack and a subsequent stall and spin to the ground. Because the pilot only held a student pilot certificate with an unknown level of training over the previous 7 years, it is likely that he did not have sufficient experience to handle the in-flight emergency.

Factual Information

On July 6, 2013, about 1845 eastern daylight time, an unregistered JDT 1600R, amateur-built airplane impacted terrain while maneuvering near Chesaning, Michigan. The pilot was fatally injured and the airplane was destroyed by impact forces and a postimpact fire. The airplane was owned and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The flight originated from the Howard Nixon Memorial Airport, at an undetermined time. A witness reported that the airplane's engine was inordinately loud and drew her attention to the airplane. She reported seeing the airplane heading north and then it banked to the west. The witness stated that as the airplane turned to the west the wings appeared to be "fluttering" and then the airplane went into a nose dive. She stated that her view of the impact was blocked by a building and once past the building she could see the plume of smoke and the burning wreckage. Another witness reported seeing the airplane heading north when it banked to the east and then began to spin out of control. He stated that the engine sounded as if it was "cutting out" as the airplane spun to the ground. The witness stated that the airplane struck the ground and immediately caught fire. The pilot had been issued a student pilot certificate on March 21, 2006. He was also issued a third class medical certificate on that same date. No pilot flight logbooks were recovered during the investigation, so it was not possible to determine what level of training the pilot had achieved. The airplane was a single-seat monoplane with a fixed conventional (tail wheel) landing gear configuration. The airplane was constructed predominately of wood with a fabric covering and was powered by a two-cylinder, two-stroke Rotax engine. The exact engine model could not be determined. The engine had a gear reduction unit which reduced the engine crankshaft speed to drive the wood two-blade propeller. An examination of the airplane revealed that most of the airplane's fuselage had been consumed by fire. The inboard sections of both wings and portions of the tail surfaces exhibited extensive fire damage. All of the airplane's flight control surfaces were attached or partially attached to the airframe. A full examination of the flight control system could not be done due to the extensive fire damage; however the portions that were examined showed no preimpact anomalies. An examination of the engine showed that all of the teeth to the smaller of the two gears in the propeller gear reduction unit were broken off. Additionally, the ball retaining cage on one of the ball bearings that supported the propeller shaft had failed, and several of the balls were missing from the bearing. A sludge-like substance resembling old oil was present in the gear reduction case. No liquid oil was found. No maintenance records for the airplane were found.

Probable Cause and Findings

The failure of the propeller reduction gearbox and the pilot’s subsequent failure to maintain adequate airspeed, which led to the airplane exceeding its critical angle-of-attack and experiencing an aerodynamic stall and spin. Contributing to the accident were the inadequate maintenance of the airplane and the student pilot’s lack of experience in performing emergency procedures.

 

Source: NTSB Aviation Accident Database

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