Cessna 210-5(205) N8427Z

Summary

On 22 July 2011 at about 18:25 local time, a Cessna 210-5(205) registered N8427Z, operated by Finkle Richard G, was involved in an accident near Darby, Montana, United States. 2 people were on board and 2 had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

22 July 2011 at 18:25

Classification

Accident

Location

Darby, Montana, United States

Coordinates

45.8833, -114.2000

Aircraft

Cessna 210-5(205)

Registration

N8427Z

Category

Airplane

Engines

1

Operator

Finkle Richard G

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Salmon → Chamberlain

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR11FA348

2 people had minor injuries.

The fatigue failure of the aluminum air intake duct, which resulted in material being ingested into the engine cylinders and a subsequent loss of engine power during cruise flight.

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

Read the full NTSB narrative

The pilot reported that, while in a cruise flight, the engine began to run rough and eventually lost power. The pilot subsequently initiated a forced landing to a gravel road, and the airplane collided with a tree during the landing roll. Postaccident examination of the engine found a 4-inch by 2-inch hole and material loss on the bottom side of the aluminum air intake duct assembly. The circumference of the hole was an irregular shape with both jagged and smooth edges/fracture surfaces. The fractures were consistent with fatigue and were possibly the result of vibration. Internal borescope examination of the cylinders revealed mechanical etching to the No. 4 and No. 6 combustion chambers and associated valve heads. The corresponding spark plugs were removed and mechanical damage was noted. The ground electrodes were bent down onto the insulators and center electrodes. No other mechanical failures were noted with the engine or airframe. It is likely that the missing aluminum duct material was ingested into the cylinders, which resulted in a loss of engine power. Although there was evidence that a weld repair had been performed on the air intake duct near the area of the hole, it could not be determined if it contributed to the hole and loss of material. A review of the airplane’s maintenance records showed no recent modifications or repairs to the engine air intake duct.

Quoted verbatim from the NTSB record.