Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Darby, Montana 59829
Friday, July 22, 2011 12:25 MDT
NTSB Narrative Summary Released at Completion of Accident
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.
NTSB Probable Cause Narrative
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.
Event Information
| Type of Event | Accident |
| Event Date | 7/22/2011 |
| Event Day of the Week | Friday |
| Time of Event | 1225 |
| Event Time Zone | Mountain Daylight Time |
| Event City | Darby |
| Event State | MONTANA |
| Event Country | -- |
| Zipcode of the event site | 59829 |
| Event Date Year | 2011 |
| Event Date Month | 7 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 455300N |
| Event Location Longitude | 1141200W |
| Event Location Airport | -- |
| Event Location Nearest Airport ID | -- |
| Indicates whether the acc/inc occurred off or on an airport | Off Airport/Airstrip |
| Distance from airport in statute miles | -- |
| Degrees magnetic from airport | -- |
| Airport Elevation | -- |
| Weather Briefing Completeness | -- |
| Investigator's weather source | Pilot |
| Time of the weather observation | |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | -- |
| Elevation of weather observation facility | -- |
| Distance of event from weather observation facility (units?) | -- |
| Time Zone of the weather observation | -- |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | Clear |
| Sky Condition for Lowest Ceiling | None |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 75 |
| Air Temperature at event time (in degrees celsius) | 24 |
| Dew Point at event time (in degress fahrenheit) | 9 |
| Wind Direction (degrees magnetic) | 340 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 3 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | -- |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | Minor |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | 2 |
| Injury Total None | -- |
| Injury Total Serious | -- |
| Injury Total All | 2 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 30418 |
| NTSB Notification Source | FAA ROC Seattle |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Oct 29 2012 3:29PM |
| User who most recently changed record | snyg |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N8427Z |
| NTSB Number | WPR11FA348 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | None |
| Flight plan Was Activated? | -- |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | CESSNA |
| Aircraft Model | 210-5(205) |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 205-0427 |
| Certified Max Gross Weight | 3300 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | -- |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | 2 |
| Cabin Crew Seats | -- |
| Passenger Seats | 4 |
| Total number of seats on the aircraft | 6 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | Annual |
| Date of Last Inspection | Jan 1 2011 12:00AM |
| Airframe hours since last inspection | 56 |
| Airframe Hours | 7343 |
| ELT Installed | Yes |
| ELT Activated | Yes |
| ELT Aided Location of Event Site | No |
| ELT Type | Unknown |
| Aircraft Owner Name | FINKLE RICHARD G |
| Aircraft Owner Street Address | -- |
| Aircraft Owner City | CLAYTON |
| Aircraft Owner State | CA |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 94517-1212 |
| Operator is an individual? | No |
| Operator Name | FINKLE RICHARD G |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | -- |
| Operator City | CLAYTON |
| Operator State | CA |
| Operator Country | USA |
| Operator Zip code | 94517-1212 |
| Operator Code | -- |
| Owner has at least one certificate | None |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | -- |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | -- |
| Indicates Domestic or International Flight | -- |
| Operator carrying Pax/Cargo/Mail | -- |
| Type of Flying (Per_Bus / Primary) | Personal |
| Second Pilot on Board | No |
| Departure Point Same as Event | No |
| Departure Airport Code | KSMN |
| Departure City | Salmon |
| Departure State | ID |
| Departure Country | USA |
| Departure Time | 1155 |
| Departure Time Zone | MDT |
| Destination Same as Local Flt | -- |
| Destination Airport Code | U79 |
| Destination City | Chamberlain |
| Destination State | ID |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Jul 31 2012 8:45PM |
| User who most recently changed record | stam |
| Since inspection or accident | Time of Accident |
| Event Location Runway Number and Location | -- |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |