Aircraft Accident/Incident Report

Ettrick, Wisconsin 54627
Sunday, April 18, 1993 9:30 CDT

NTSB Narrative Summary Released at Completion of Accident

WITNESSES REPORTED THAT THE AIRPLANE FIRST SOUNDED NORMAL, AND THEN ITS ENGINE RPM INCREASED, FOLLOWED BY AN EXPLOSION & SMOKE. THREE WITNESSES OBSERVED THE AIRPLANE DURING AN UNCONTROLLED VERTICAL DESCENT. ONE STATED THE AIRPLANE EXPLODED APPROX 100 FT ABOVE THE GROUND. ANOTHER STATED HE OBSERVED THE AIRPLANE DESCENDING VERTICALLY, LOSING SIGHT OF IT JUST PRIOR TO OBSERVING FIRE AND SMOKE. THE THIRD STATED HE OBSERVED THE AIRPLANE FLYING STRAIGHT AND LEVEL, THEN SUDDENLY PITCH DOWN. DURING THE DESCENT, HE OBSERVED GREY SMOKE COMING FROM THE AIRPLANE. A CAN OF TCP FUEL TREATMENT WAS FOUND IN THE BURNT WRECKAGE. THE FILLER NECK AND CAP HAD DISTORTIONS WHICH DID NOT MATCH. TCP IS COMPRISED MAINLY OF TOLUENE, A HIGHLY VOLATILE SUBSTANCE. FUMES FROM A TOLUENE-BASED FLUID SUCH AS TCP COULD EXPLODE DURING THE LIGHTING OF A CIGARETTE. THE CAN WAS KEPT IN THE BAGGAGE COMPARTMENT BY THE OWNER. EIGHT PIECES OF WINDSHIELD PLEXIGLASS WERE FOUND AROUND THE IMPACT CRATER; THE REMAINDER OF THE WINDSHIELD WAS NOT FOUND.

NTSB Probable Cause Narrative

AN INFLIGHT EXPLOSION OF A TOLUENE-BASED FLUID INSIDE THE AIRPLANE'S COCKPIT.

Event Information

Type of Event Accident
Event Date 4/18/1993
Event Day of the Week Sunday
Time of Event 930
Event Time Zone Central Daylight Time
Event City ETTRICK
Event State WISCONSIN
Event Country --
Zipcode of the event site 54627
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 0
Degrees magnetic from airport 0
Airport Elevation --
Weather Briefing Completeness Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 945 Central Daylight Time
Direction of event from weather observation facility (degrees) 175
Weather Observation Facility ID LSE
Elevation of weather observation facility 654
Distance of event from weather observation facility (units?) 21
Time Zone of the weather observation CDT
Lighting Conditions Day
Lowest Ceiling Height 1000
Lowest Non-Ceiling Height 1000
Sky/Lowest/Cloud Conditions Unknown
Sky Condition for Lowest Ceiling Overcast
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 8
Air Temperature at event time (in degrees celsius) 11
Dew Point at event time (in degress fahrenheit) 7
Wind Direction (degrees magnetic) 180
Variable Wind Indicator Unknown
Wind Speed (knots) 13
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Fatal
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal 2
Injury Total Minor --
Injury Total None --
Injury Total Serious --
Injury Total All 2
Investigating Agency NTSB
NTSB Docket Number (internal use) 890
NTSB Notification Source --
NTSB Notification Date Apr 18 1993 12:00AM
NTSB Notification Time 1100
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 11 2000 1:13PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N8337L
NTSB Number CHI93FA139
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Destroyed
Aircraft Fire In-flight
Aircraft Explosion In-flight
Aircraft Manufacturer's Full Name CESSNA
Aircraft Model 172I
Aircraft Series Identifier 172I
Aircraft Serial Number 17256537
Certified Max Gross Weight 2300
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 Jan 6 1993 12:00AM
Airframe hours since last inspection --
Airframe Hours --
ELT Installed Yes
ELT Activated Unknown
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name LEO G. STOKES
Aircraft Owner Street Address BOX 626
Aircraft Owner City MONTICELLO
Aircraft Owner State MN
Aircraft Owner Country
Aircraft Owner Zipcode 55362
Operator is an individual? --
Operator Name LEO G. STOKES
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address BOX 626
Operator City MONTICELLO
Operator State MN
Operator Country
Operator Zip code 55362
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 20Y
Departure City MONTICELLO
Departure State MN
Departure Country
Departure Time 830
Departure Time Zone CDT
Destination Same as Local Flt --
Destination Airport Code UGN
Destination City WAUKEGAN
Destination State IL
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 --