Aircraft Accident/Incident Report

Eustis, Florida 32726
Saturday, July 12, 1997 15:15 EDT

NTSB Narrative Summary Released at Completion of Accident

The flight was tracking northward, when the pilot said he experienced 'minimal lift' at an altitude of about 4,000 feet mean sea level (msl). A ground witness said there was a cumulus cloud in the vicinity just before the accident. The pilot said that when he got near the cloud the lift increased, at first to about 300 feet per minute (fpm), then to about 600 fpm. As the glider passed 4,000 feet msl, there was a rapid rate of increase to over 1,000 fpm. The pilot estimated that the glider climbed from 4,000 feet msl to about 6,200 feet msl in about 20 seconds. At peak altitude the right wing separated from the glider, at the root. The pilot said he believed the wing separated upward, and made contact with the top of the canopy. He attempted numerous combinations of control imputes. The glider yawed, rolled and pitched with little response to the controls, and finally became upright in a high yaw rate condition. The glider impacted in a thick stand of 80-to 100-foot tall pine trees. The reported cloud bases at the time of the accident were reported to be 4,300 feet msl. The floor of the Class B airspace was 3,000 feet msl at the location of the accident, and the aircraft was operating at the time of the accident without gyro instruments. A section of the right wing front spar was sent to the NTSB Materials Laboratory, Washington, DC, for examination. The examination revealed that the fracture features and deformations were all consistent with 'overstress separations.' No evidence of fatigue or any type of cracking was found.

NTSB Probable Cause Narrative

an in-flight separation of the right wing, and subsequent impact with trees. Factors in this accident were thermal lift and turbulence in clouds.

Event Information

Type of Event Accident
Event Date 7/12/1997
Event Day of the Week Saturday
Time of Event 1515
Event Time Zone Eastern Daylight Time
Event City EUSTIS
Event State FLORIDA
Event Country --
Zipcode of the event site 32726
Event Date Year 1997
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 4300
Sky/Lowest/Cloud Conditions Scattered
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) 34
Dew Point at event time (in degress fahrenheit) --
Wind Direction (degrees magnetic) 220
Variable Wind Indicator Unknown
Wind Speed (knots) 5
Wind Velocity Indicator Unknown
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) 598
NTSB Notification Source --
NTSB Notification Date Jul 12 1997 12:00AM
NTSB Notification Time 1600
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 8 2000 12:25PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N9927J
NTSB Number MIA97LA211
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 Schweizer
Aircraft Model SGS-1-26B
Aircraft Series Identifier SGS-1-26B
Aircraft Serial Number 346
Certified Max Gross Weight 600
Aircraft Category Glider
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 --
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Dec 1 1996 12:00AM
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 DIANE C. BLAKE
Aircraft Owner Street Address 529 BRYN MAWR ST.
Aircraft Owner City ORLANDO
Aircraft Owner State FL
Aircraft Owner Country
Aircraft Owner Zipcode 32804
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 Yes
Departure Airport Code X55
Departure City
Departure State
Departure Country
Departure Time 1345
Departure Time Zone EDT
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 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 --