Los Banos Airport
Aircraft Accident/Incident Report

Los Banos, California 93635
Wednesday, December 18, 2002 15:21 PST

NTSB Narrative Summary Released at Completion of Accident

The pilot and aircraft maintenance technician were performing a post maintenance test flight when a vibration occurred, followed by a total loss of engine power. The commercial certificated helicopter pilot made a forced landing in a muddy field, during which the helicopter received structural damage. Post accident examination revealed a failed exhaust valve in the number 3 cylinder, and that two exhaust spring seats had been installed, one on top of the other, causing excessive spring/valve pressures. The engine had been overhauled about 1.5 service hours prior to the loss of engine power.

NTSB Probable Cause Narrative

The improper engine overhaul by other maintenance personnel, which resulted in an exhaust valve failure and a total loss of engine power while in maneuvering flight.

Event Information

Type of Event Accident
Event Date 12/18/2002
Event Day of the Week Wednesday
Time of Event 1521
Event Time Zone Pacific Standard Time
Event City Los Banos
Event State CALIFORNIA
Event Country --
Zipcode of the event site 93635
Event Date Year 2002
Event Date Month 12
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 370347N
Event Location Longitude 1205210W
Event Location Airport Los Banos
Event Location Nearest Airport ID LSN
Indicates whether the acc/inc occurred off or on an airport On Airport
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation 119
Weather Briefing Completeness Not pertinent
Investigator's weather source Weather Observation Facility
Time of the weather observation 1453 Pacific Standard Time
Direction of event from weather observation facility (degrees) 45
Weather Observation Facility ID MCE
Elevation of weather observation facility 153
Distance of event from weather observation facility (units?) 22
Time Zone of the weather observation PST
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) 3
Wind Direction (degrees magnetic) 10
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 3
Wind Velocity Indicator --
Wind Gust Indicator Unknown
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 30.21
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor --
Injury Total None 2
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 16900
NTSB Notification Source FAA
NTSB Notification Date Dec 18 2002 12:00AM
NTSB Notification Time 1656
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Dec 28 2004 12:45PM
User who most recently changed record NTSB\JOHB
Basic weather conditions Visual Meteorological Cond
FAA District Office WP-FAT-FSDO

Aircraft Involved

Aircraft #1

Aircraft Registration Number N642KC
NTSB Number LAX03LA052
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 Schweizer
Aircraft Model 269C
Aircraft Series Identifier --
Aircraft Serial Number S1682
Certified Max Gross Weight 2050
Aircraft Category Helicopter
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 2
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection 100 Hour
Date of Last Inspection Aug 23 2002 12:00AM
Airframe hours since last inspection 1.5
Airframe Hours 3784.6
ELT Installed No
ELT Activated No
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name John Raven
Aircraft Owner Street Address --
Aircraft Owner City Campbell
Aircraft Owner State CA
Aircraft Owner Country USA
Aircraft Owner Zipcode 95008
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 LSN
Departure City Los Banos
Departure State CA
Departure Country USA
Departure Time 1500
Departure Time Zone PST
Destination Same as Local Flt dest & departure same, accident can occur anywhere
Destination Airport Code --
Destination City --
Destination State --
Destination Country --
Specific Phase of Flight Landing
Report sent to ICAO? No
Evacuation occurred No
Date of most recent change to record Oct 25 2004 11:26AM
User who most recently changed record LABJ
Since inspection or accident Last Inspection
Event Location Runway Number and Location NA
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --