Aircraft Accident/Incident Report

Miles City, Montana 59301
Sunday, November 4, 2001 18:15 MST

NTSB Narrative Summary Released at Completion of Accident

During en route cruise, the number four cylinder exhaust valve guide separated from its associated cylinder head. When the aircraft was approximately 12 miles from the airport, the head of the number four cylinder exhaust valve separated from the valve stem. The exhaust valve head then dropped into the number four cylinder where it repeatedly impacted the piston dome and the cylinder head ceiling. This was followed by approximately 30 percent of the piston dome failing inward, resulting in the pressurization of the crankcase through the open exhaust valve port. As a result of the pressurization of the case, one of the number six cylinder pushrod-to-crankcase seals was forced off of its crankcase mounting surface, allowing the majority of the oil to escape from the engine. Soon thereafter, due to thermal stress, the number one connecting rod separated from the crankshaft and punched holes in the crankcase near the number one and number two crankshaft journals. After experiencing a total loss of power, the pilot attempted to land on the uneven rolling terrain, but due to the darkness of the night collided with the terrain.

NTSB Probable Cause Narrative

The separation of the number four cylinder exhaust valve guide from the cylinder head, leading to the failure of the exhaust valve stem and the catastrophic failure of the engine while in cruise flight. Factors include the necessity of attempting a forced landing in rolling/hilly terrain on a very dark night.

Event Information

Type of Event Accident
Event Date 11/4/2001
Event Day of the Week Sunday
Time of Event 1815
Event Time Zone Mountain Standard Time
Event City Miles City
Event State MONTANA
Event Country --
Zipcode of the event site 59301
Event Date Year 2001
Event Date Month 11
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude --
Event Location Longitude --
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 Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 1753 Mountain Standard Time
Direction of event from weather observation facility (degrees) 270
Weather Observation Facility ID KMLS
Elevation of weather observation facility 2628
Distance of event from weather observation facility (units?) 12
Time Zone of the weather observation MST
Lighting Conditions Night/Dark
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) 20
Air Temperature at event time (in degrees celsius) 13
Dew Point at event time (in degress fahrenheit) -6
Wind Direction (degrees magnetic) 130
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 6
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 30.03
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury Fatal
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal 1
Injury Total Minor --
Injury Total None --
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 12375
NTSB Notification Source FAA Operation Center
NTSB Notification Date Nov 4 2001 12:00AM
NTSB Notification Time 1830
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Oct 24 2002 3:20PM
User who most recently changed record NTSB\MONR
Basic weather conditions Visual Meteorological Cond
FAA District Office Helena FSDO

Aircraft Involved

Aircraft #1

Aircraft Registration Number N8347T
NTSB Number SEA02FA009
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? No
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Cessna
Aircraft Model 175C
Aircraft Series Identifier --
Aircraft Serial Number 17557047
Certified Max Gross Weight 2450
Aircraft Category Airplane
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 4
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Dec 30 2000 12:00AM
Airframe hours since last inspection 84
Airframe Hours 2450
ELT Installed Yes
ELT Activated Yes
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name Terry I. Stubblefield
Aircraft Owner Street Address On File
Aircraft Owner City Miles City
Aircraft Owner State MT
Aircraft Owner Country USA
Aircraft Owner Zipcode 59301
Operator is an individual? No
Operator Name --
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address --
Operator City --
Operator State --
Operator Country --
Operator Zip code --
Operator Code --
Owner has at least one certificate None
Other Operator of large aircraft? --
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 9D2
Departure City Buffalo
Departure State SD
Departure Country USA
Departure Time 1700
Departure Time Zone MST
Destination Same as Local Flt --
Destination Airport Code MLS
Destination City Miles City
Destination State MT
Destination Country USA
Specific Phase of Flight Cruise
Report sent to ICAO? No
Evacuation occurred No
Date of most recent change to record Jul 15 2002 12:01PM
User who most recently changed record STAM
Since inspection or accident --
Event Location Runway Number and Location --
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --