Aircraft Accident/Incident Report

Tracy, California 95376
Monday, July 29, 1996 6:15 PDT

NTSB Narrative Summary Released at Completion of Accident

The pilot reported that the engine quit while he was en route to a job and he landed in an alfalfa field. The aircraft collided with a ditch which was obscured by the crops. A postcrash fire erupted and consumed the aircraft. The aircraft was examined by an FAA airworthiness inspector. He reported that the engine crankshaft would rotate; however, no corresponding valve action was noted on any cylinder. The inspector observed a disassembly of the engine and reported that the eight screws which secure the crankshaft hub to the crankshaft gear had sheared. The crankshaft gear rotates all accessory drive gears, including the magnetos.

NTSB Probable Cause Narrative

A loss of engine power due to the disengagement of the crankshaft gear from it's hub due to the overload shear of the eight retaining screws.

Event Information

Type of Event Accident
Event Date 7/29/1996
Event Day of the Week Monday
Time of Event 615
Event Time Zone Pacific Daylight Time
Event City TRACY
Event State CALIFORNIA
Event Country --
Zipcode of the event site 95376
Event Date Year 1996
Event Date Month 7
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 Pilot
Time of the weather observation 0
Direction of event from weather observation facility (degrees) 0
Weather Observation Facility ID
Elevation of weather observation facility 0
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 20
Air Temperature at event time (in degrees celsius) 18
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) 0
Variable Wind Indicator Unknown
Wind Speed (knots) 0
Wind Velocity Indicator Calm
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) --
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury None
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None 1
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 812
NTSB Notification Source --
NTSB Notification Date Jul 29 1996 12:00AM
NTSB Notification Time 920
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 8 2000 10:12AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N68251
NTSB Number LAX96LA291
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 137: Agricultural
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Destroyed
Aircraft Fire Ground
Aircraft Explosion None
Aircraft Manufacturer's Full Name Boeing
Aircraft Model A75N1
Aircraft Series Identifier A75-N1
Aircraft Serial Number 75-7976
Certified Max Gross Weight 3500
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 1
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Jun 26 1996 12:00AM
Airframe hours since last inspection 85
Airframe Hours 3779
ELT Installed No
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name TRINKEL & BOYS
Aircraft Owner Street Address 31244 S. HWY 33
Aircraft Owner City TRACY
Aircraft Owner State CA
Aircraft Owner Country
Aircraft Owner Zipcode 95376
Operator is an individual? --
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 MBNG
Owner has at least one certificate Yes - certificate holder
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Agriculture
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not Unknown
Indicates Domestic or International Flight Unknown
Operator carrying Pax/Cargo/Mail Unknown
Type of Flying (Per_Bus / Primary) Aerial Application
Second Pilot on Board No
Departure Point Same as Event Yes
Departure Airport Code
Departure City
Departure State
Departure Country
Departure Time 600
Departure Time Zone PDT
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 Cruise
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Dec 9 2002 10:30AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --