Aircraft Accident/Incident Report

Bullhead City, Arizona 86430
Sunday, April 25, 1993 17:40 MST

NTSB Narrative Summary Released at Completion of Accident

The aircraft was in cruise flight at 7,500 feet when the pilot heard five loud bangs after which the engine seized. The pilot attempted an emergency landing in a farm field and collided with rough terrain and a fence. Examination of the maintenance records revealed that the engine had been in service for about 35 years and had been majored twice during 2,000 total operating hours. The most recent major overhaul occurred 13 years and 344 hours prior to the accident. Internal examination of the engine disclosed that the crankshaft had failed in fatigue at the number two main journal. Detailed metallurgical examination revealed that the number one bearing insert had been mispositioned during assembly of the crankcase causing a localized oil flow restriction to the main bearings and an eventual fatigue failure of the crankshaft.

NTSB Probable Cause Narrative

a fatigue failure of the crankshaft due to improper assembly of the engine during the major overhaul.

Event Information

Type of Event Accident
Event Date 4/25/1993
Event Day of the Week Sunday
Time of Event 1740
Event Time Zone Mountain Standard Time
Event City BULLHEAD CITY
Event State ARIZONA
Event Country --
Zipcode of the event site 86430
Event Date Year 1993
Event Date Month 4
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 0
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) 40
Air Temperature at event time (in degrees celsius) 26
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 3
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 876
NTSB Notification Source --
NTSB Notification Date Apr 27 1993 12:00AM
NTSB Notification Time 2015
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 11 2000 1:14PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N6698A
NTSB Number LAX93FA190
Missing Aircraft Indicator N
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 172
Aircraft Series Identifier 172
Aircraft Serial Number 172 28798
Certified Max Gross Weight 2200
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 1 1993 12:00AM
Airframe hours since last inspection 15
Airframe Hours 3600
ELT Installed Yes
ELT Activated No
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name ROBERT J. THOMAS
Aircraft Owner Street Address 42236 N. 7TH ST.
Aircraft Owner City PHOENIX
Aircraft Owner State AZ
Aircraft Owner Country
Aircraft Owner Zipcode 85027
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
Owner has at least one certificate None
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
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 0L9
Departure City OVERTON
Departure State NV
Departure Country
Departure Time 0
Departure Time Zone
Destination Same as Local Flt --
Destination Airport Code DVT
Destination City PHOENIX
Destination State AZ
Destination Country
Specific Phase of Flight Cruise
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:34AM
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 --