Stilwell/Cherokee Nation Airport
Aircraft Accident/Incident Report

Stilwell, Oklahoma 74960
Thursday, March 20, 1997 17:35 CST

NTSB Narrative Summary Released at Completion of Accident

The pilot (plt) departed Cookson, OK, in a homebuilt aircraft (acft) for an approximate 30 minute flight to Stilwell, OK. Witnesses at Stilwell said he made a low pass on a northerly heading (about 50 ft off the ground) at a high rate of speed. One witness estimated the acft was traveling faster than 200 mph, when he saw the acft's right wing skin separate from the acft. The right wing then came off. The acft was observed to roll several times & travel about 1100 ft before it impacted the ground. Postimpact examination of the wreckage revealed a fracture in the wing spar about 18 inches in from the right wing tip. There was a discoloration in the fracture, which had the appearance of a varnish like substance. An FAA inspector reported that 'there were different color glue joints in the wing construction indicating that there were different kinds of glue used.' Also, the failure mode differed; the dark glue joints failed in the wooden structure, where as, the other glue joints failed in the bond. Some of the wing joints that had failed had discoloration between the rib & the wooden skin. The inspector suggested that 'either improper clamping during construction, prevarnishing of the contact surfaces, or bond separation followed by moisture weathering could have caused this.' The plt had purchased the homebuilt acft on 10/1/96. It had been originally certificated for flight on 10/27/72. On 2/11/73, it had been damaged during a takeoff mishap, & 'new wing construction' had been performed.

NTSB Probable Cause Narrative

failure of the right wing spar and/or debonding of the right wing skin, which resulted in separation of the wing skin and a portion of the right wing, during high speed flight. Factors related to the accident were: previous wing damage and inadequate maintenance by other (unknown) personnel.

Event Information

Type of Event Accident
Event Date 3/20/1997
Event Day of the Week Thursday
Time of Event 1735
Event Time Zone Central Standard Time
Event State OKLAHOMA
Event Country --
Zipcode of the event site 74960
Event Date Year 1997
Event Date Month 3
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Nearest Airport ID O11
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 --
Weather Briefing Completeness Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 1653 Central Standard Time
Direction of event from weather observation facility (degrees) 155
Weather Observation Facility ID FSM
Elevation of weather observation facility 469
Distance of event from weather observation facility (units?) 25
Time Zone of the weather observation CST
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) 10
Air Temperature at event time (in degrees celsius) 22
Dew Point at event time (in degress fahrenheit) 7
Wind Direction (degrees magnetic) 270
Variable Wind Indicator Unknown
Wind Speed (knots) 10
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 1
Injury Total Minor --
Injury Total None --
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 557
NTSB Notification Source --
NTSB Notification Date Mar 24 1997 12:00AM
NTSB Notification Time 746
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 8 2000 12:09PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N86T
NTSB Number FTW97FA135
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 None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Teschendorf
Aircraft Model CASSUTT SPORT
Aircraft Series Identifier CASSUTT SP
Aircraft Serial Number T1
Certified Max Gross Weight 929
Aircraft Category Airplane
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? Yes
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 Unknown
Date of Last Inspection --
Airframe hours since last inspection --
Airframe Hours --
ELT Installed No
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name DANIEL K. STONE
Aircraft Owner Street Address HC 73, BOX 56-1A
Aircraft Owner City PARK HILL
Aircraft Owner State OK
Aircraft Owner Country
Aircraft Owner Zipcode 74451
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 44M
Departure City COOKSON
Departure State OK
Departure Country
Departure Time 1705
Departure Time Zone CST
Destination Same as Local Flt crash at destination city
Destination Airport Code 011
Destination City
Destination State OK
Destination Country
Specific Phase of Flight Maneuvering
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 --