Aircraft Accident/Incident Report

Oak Shores, California 93446
Saturday, April 27, 2002 17:45 PDT

NTSB Narrative Summary Released at Completion of Accident

The airplane collided with trees following a loss of engine power. A passenger heard a "roar" through the four-way intercom. The certified flight instructor (CFI) and the student pilot checked the oil pressure and fuel pressure; both were "good." The CFI pointed to the left and directed the student toward a private strip. During or immediately following the left turn, the CFI said, "I've got it." The student looked back at the two passengers, and motioned with his right hand that they were going to land at the strip. The last thing that the passenger remembered was contact with the trees and coming to rest. The airplane cleared a ridge top, but collided with trees about 1/4 mile from the landing strip. The spark plug for cylinder no. 1 sustained mechanical damage and contained metallic debris. The head of the cylinder no. 1 exhaust valve was missing, and the top of the piston exhibited mechanical damage across its entire surface. Metallurgists examined the valve and cylinder. The valve stem was broken and remained in the valve guide. The stem fractured and there were numerous secondary cracks below the fracture surface. The areas around the valve seats were severely damaged. The fracture surface condition was such that the fracture mechanism could not be determined. The secondary cracks were only in a local area where the material was severely battered and deformed. Many of the cracks were slightly curved and/or did not appear to be perpendicular to the outer or inner surface. These types of cracks are most likely to occur where surfaces have overlapped, or are the result of the excessive local strains in the area. There were no material or dimensional abnormalities that would suggest fatigue. The manufacturer issued maintenance instructions describing methods for determining exhaust valve and guide condition. This maintenance function was optional for the operator, and maintenance records indicated that this had not been done. Although the diameter of the exhaust valve stem was slightly below the specified diameter, this would have a small affect on overall stresses. However, a small change in diameter of the valve stem significantly changes the amount of clearance between the exhaust valve stem and the exhaust valve guide. Excessive clearance can lead to exhaust valve sticking, which can lead to overstress fracture. The engine total time was 2,079 hours, and it had not been overhauled since it was new in 1975. The manufacturer recommended overhaul at 2,000 hours or after 12 years of service life. Given the high hours on this engine and the number of years since overhaul, it was likely that the failure was due to exhaust valve sticking.

NTSB Probable Cause Narrative

the number 1 cylinder exhaust valve fractured and separated resulting in a loss of engine power and an off airport forced landing. A finding in the accident was the owner's failure to maintain the engine in accordance with the manufacturer's recommendations.

Event Information

Type of Event Accident
Event Date 4/27/2002
Event Day of the Week Saturday
Time of Event 1745
Event Time Zone Pacific Daylight Time
Event Country --
Zipcode of the event site 93446
Event Date Year 2002
Event Date Month 4
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 354727N
Event Location Longitude 1205937W
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 Not pertinent
Investigator's weather source Weather Observation Facility
Time of the weather observation 1753 Pacific Daylight Time
Direction of event from weather observation facility (degrees) 95
Weather Observation Facility ID PRB
Elevation of weather observation facility 836
Distance of event from weather observation facility (units?) 21
Time Zone of the weather observation PDT
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) 10
Air Temperature at event time (in degrees celsius) 12
Dew Point at event time (in degress fahrenheit) 4
Wind Direction (degrees magnetic) --
Variable Wind Indicator Variable
Wind Speed (knots) 4
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 30.01
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 3
Injury Total Minor --
Injury Total None --
Injury Total Serious 1
Injury Total All 4
Investigating Agency NTSB
NTSB Docket Number (internal use) 16304
NTSB Notification Source FAA
NTSB Notification Date Apr 28 2002 12:00AM
NTSB Notification Time 720
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Sep 29 2004 1:02PM
User who most recently changed record NTSB\MONR
Basic weather conditions Visual Meteorological Cond
FAA District Office WP-SJC-FSDO

Aircraft Involved

Aircraft #1

Aircraft Registration Number N9180S
NTSB Number LAX02FA148
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? No
Damage Destroyed
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Beech
Aircraft Model C23
Aircraft Series Identifier --
Aircraft Serial Number M-1801
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 Apr 6 2001 12:00AM
Airframe hours since last inspection 118
Airframe Hours 2097
ELT Installed Yes
ELT Activated Yes
ELT Aided Location of Event Site Yes
ELT Type --
Aircraft Owner Name Stephen W. Meester
Aircraft Owner Street Address On File
Aircraft Owner City Oakdale
Aircraft Owner State CA
Aircraft Owner Country USA
Aircraft Owner Zipcode 95364
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) Instructional
Second Pilot on Board Yes
Departure Point Same as Event No
Departure Airport Code L52
Departure City SAN LUIS OBISPO
Departure State CA
Departure Country USA
Departure Time 1630
Departure Time Zone PDT
Destination Same as Local Flt --
Destination Airport Code 3O8
Destination City HARRIS RANCH
Destination State CA
Destination Country USA
Specific Phase of Flight Maneuvering - turn to landing area (emergency)
Report sent to ICAO? No
Evacuation occurred No
Date of most recent change to record Aug 11 2004 6:18PM
User who most recently changed record COOS
Since inspection or accident Time of Accident
Event Location Runway Number and Location NA
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --