Aircraft Accident/Incident Report

Suring, Wisconsin 54174
Thursday, July 16, 2009 6:40 CDT

NTSB Narrative Summary Released at Completion of Accident

The pilot reported that the engine began to run very rough during a turn at low altitude. The engine suddenly seized so he made an emergency landing to a wheat field. During the landing, the left main gear collapsed and the left wing and nose of the aircraft dug into the soft soil, sustaining substantial damage. A teardown inspection of the engine revealed fretting wear scars on the crankcase backbone between the number two and three main bearing supports, and the number one, two, and three camshaft journal supports. The number one, two, three, four, and five main crankshaft main bearing supports exhibited fretting wear scars, and the number two and three supports exhibited mechanical damage from bearing shift and rotation. Additionally, the number two intermediate crankshaft main bearings had extruded from their crankshaft positions in the left and right case halves. An unapproved red sealant had been applied to the crankcase backbone. The above signatures are all consistent with an engine crankcase assembly that had lost its through-bolt torque. The crankshaft was fractured through at the number four short cheek between the number two main bearing journal and the number three connecting rod journal. A metallurgical examination of the fracture surface revealed crack arrest marks, which were indicative of a fatigue fracture which emanated from the surface of the number two main bearing journal. The heat treatment of the crankshaft met the manufacturer’s specifications. An examination of the engine logbooks revealed that the engine’s total time was about 1,778 hours and it had about 500 hours since the last major overhaul. The engine’s last overhaul was conducted on September 30, 1986, almost 23 years since the last major overhaul. The engine manufacturer recommends that when the aircraft is used in aerial spraying, the engine be overhauled after an accumulation of 1,200 hours or twelve (12) years, whichever occurs first.

NTSB Probable Cause Narrative

A loss of engine power resulting from the fatigue failure of the crankshaft due to the loss of engine case through-bolt torque. Contributing to the engine failure was the operator's failure to overhaul the engine in accordance with the manufacturer's recommended guidelines.

Event Information

Type of Event Accident
Event Date 7/16/2009
Event Day of the Week Thursday
Time of Event 640
Event Time Zone Central Daylight Time
Event City Suring
Event State WISCONSIN
Event Country --
Zipcode of the event site 54174
Event Date Year 2009
Event Date Month 7
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 445303N
Event Location Longitude 0882729W
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 --
Investigator's weather source Weather Observation Facility
Time of the weather observation 610 Central Daylight Time
Direction of event from weather observation facility (degrees) 160
Weather Observation Facility ID GRB
Elevation of weather observation facility 695
Distance of event from weather observation facility (units?) 30
Time Zone of the weather observation CDT
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) 13
Dew Point at event time (in degress fahrenheit) 11
Wind Direction (degrees magnetic) 260
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 5
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 29.87
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 1
Injury Total Serious --
Injury Total All --
Investigating Agency NTSB
NTSB Docket Number (internal use) 26682
NTSB Notification Source FAA-AGL-ROC
NTSB Notification Date --
NTSB Notification Time --
Fiche Number and/or location -used to find docket information --
Date of most recent change to record Apr 16 2010 4:15PM
User who most recently changed record johb
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N9747G
NTSB Number CEN09LA447
Missing Aircraft Indicator --
Federal Aviation Reg. Part Part 137: Agricultural
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 A188B
Aircraft Series Identifier --
Aircraft Serial Number 18801587T
Certified Max Gross Weight 4200
Aircraft Category Airplane
Aircraft Registration Class --
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 Oct 23 2008 12:00AM
Airframe hours since last inspection --
Airframe Hours 2211
ELT Installed No
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name NICOLET AIR LLC
Aircraft Owner Street Address 11008 HWY 64E
Aircraft Owner City SURING
Aircraft Owner State WI
Aircraft Owner Country USA
Aircraft Owner Zipcode 54174
Operator is an individual? No
Operator Name NICOLET AIR LLC
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address 11008 HWY 64E
Operator City SURING
Operator State WI
Operator Country USA
Operator Zip code 54174
Operator Code 3WAG
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 --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Aerial Application
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code --
Departure City Suring
Departure State WI
Departure Country USA
Departure Time 620
Departure Time Zone CDT
Destination Same as Local Flt --
Destination Airport Code --
Destination City Private Field
Destination State WI
Destination Country USA
Specific Phase of Flight --
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Feb 25 2010 9:59AM
User who most recently changed record silj
Since inspection or accident Last Inspection
Event Location Runway Number and Location N/A
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --