20170219007759A

The subject aircraft departed kfrg February 19, 2017 approximately 0900 eastern standard time. During the flight while near the statue of liberty the aircraft started to develop engine power problems and was unable to maintain altitude. The pilot declared an emergency and headed towards land and made a forced landing onto a residential street. The aircraft struck several trees numerous power lines and several automobiles before coming to its final resting position.

The following was noted upon arrival at the accident scene.

The aircraft came to rest inverted and against a concrete stairway of a residential home. The left hand wing was completely separated from the aircraft and broken into several pieces, the fuel tank was completely breached and contained no fuel. The right hand wing was partially separated and remained mostly intact the fuel tank was partially breached and dripping fuel. Numerous pieces and parts from the aircraft were found scattered over the course of two blocks, the propeller showed signs of rotational damage on both blades. Approximately ten gallons of fuel was recovered from the right wing tank prior to the aircraft being moved by the recovery team, approximately five gallons of fuel was on the ground under the right wing and around the aircraft.

An interview with the pilot was conducted at a local hospital, the pilot stated that he was on a personal flight that departed from kfrg at approximately 0900 eastern standard time, he said he was approximately one hour into his flight and was heading south over the hudson river near the statue of liberty when he started to notice the aircraft was losing altitude unintentionally. The pilot stated he went through a visual check of all aircraft instrumentation and saw nothing out of the ordinary he then advanced all engine and propeller controls to full forward. The pilot stated this did not help and the aircraft was still losing altitude and the engine was losing power. He declared an emergency over the aircraft radio headed for land and picked out the closest street he could land on.

A detailed inspection of the aircraft and engine assembly was conducted with representatives from the engine manufacturer, aircraft manufacturer and the NTSB. The inspection took place at a secure recovery facility located in clayton, DE. This inspector was present and took part in the inspection.

The inspection revealed the following:

The engine was able to be rotated by turning the propeller, some compression was found present in the number one, two and four cylinders, the number three cylinder had no compression at all. Inspection of the number three cylinder revealed the intake valve had failed and had been ingested into the cylinder. A large hole approximately the size of the diameter of the valve stem was found in the cylinder head next to the intake port. The piston was severely damaged and the cylinder wall was severely scored and damaged. The intake valve stem was recovered from the oil sump and valve head was recovered from the intake manifold. Inspection of the valve stem found the tip of the stem had sheared off allowing the valve to drop into the number three cylinder. A detailed inspection of the number three cylinder intake and exhaust valve hydraulic tappet assemblies found the hydraulic tappet plunger assembly was installed backwards and not in accordance with the manufactures maintenance and overhaul manuals. The plunger assemblies consist of the hydraulic tappet plunger, plunger spring, ball check valve and cylinder. Further inspection of the remaining cylinders found all of the hydraulic tappets had the plunger assemblies installed backwards and not in accordance with the manufacturer's maintenance and overhaul manuals. A review of the aircraft maintenance records found the engine crankcase assembly was replaced thirty five (35) flight hours prior to this accident, by a certificated airframe and powerplant mechanic.