Zivko Aeronautics EDGE 540 N9ND

Summary

On 19 February 1999 at about 00:40 local time, a Zivko Aeronautics EDGE 540 registered N9ND was involved in an accident near Livermore, California, United States. One person was on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

19 February 1999 at 00:40

Classification

Accident

Location

Livermore, California, United States

Coordinates

37.6808, -121.7503

Aircraft

Zivko Aeronautics EDGE 540

Registration

N9ND

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Tracy → San Carlos

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

LAX99LA103

Nobody was injured.

The manufacturer's inadequate quality control procedures, which allowed an improperly manufactured crankshaft to be shipped, resulting in the separation of one counterweight from the crankshaft lug and the subsequent catastrophic internal failure of the engine.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The pilot said he was in normal cruise flight when the 200-hour since new Lycoming AEIO-540 engine began to over speed. The pilot said a roughness, which progressively worsened, was associated with the onset of the over speed event. He stated that he was unsuccessful in regaining control of the engine and initiated a power-off forced landing to a clear area next to a highway. The aircraft touched down in soft, muddy soil and the landing gear was torn out of the structure. Cracks were found across the rear of the engine case between the Nos. 5 and 6 cylinders. Disassembly of the engine revealed that one of the two counterweight rollers had become dislodged from the corresponding counterweight crankshaft lug bore and precipitated a catastrophic internal failure of the No. 6 connecting rod. Detailed examination of the separated counterweight crankshaft lug bore revealed rotational scoring around the inside diameter of the hole, while the roller bushing was broken in two pieces and displayed rotational scoring marks around the outside diameter. The designed bushing to bore clearance provides for an interference fit. The problematic lug bore was measured for circularity, position, and diameter with respect to design specifications. The lug bore was found outside of acceptable tolerances in all areas. According to Textron Lycoming and the FAA, a small number of crankshafts by serial number where produced with the lug bore(s) misreamed to an out of round condition during that stage of the manufacturing process. The accident crankshaft by serial number was outside of the believed problem range.

Quoted verbatim from the NTSB record.