Aircraft Accident/Incident Report

Boulder, Colorado 80301
Saturday, November 2, 1996 13:44 MST

NTSB Narrative Summary Released at Completion of Accident

A witness observe the glider to come from behind the mountains in a wings level attitude, traveling in a northeast direction. She said the glider made a complete 360-degree roll to the right about its longitudibal axis. The glider rolled out on a more easterly heading, then began losing altitude in an increasingly nose down attitude and entered either a spin or spiral. She then observed the wings to fail and fold aft along the fuselage. According to NTSB's metallurgist's report, 'all fractures in both wing sections were typical of overstress separations. No evidence of fatigue or other types of preexisting cracking was found.'

NTSB Probable Cause Narrative

The pilot exceeding the design stress limits of the aircraft by performing an aerobatic maneuver, resulting in total failure of the wing spar.

Event Information

Type of Event Accident
Event Date 11/2/1996
Event Day of the Week Saturday
Time of Event 1344
Event Time Zone Mountain Standard Time
Event City BOULDER
Event State COLORADO
Event Country --
Zipcode of the event site 80301
Event Date Year 1996
Event Date Month 11
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 Not pertinent
Investigator's weather source Weather Observation Facility
Time of the weather observation 1345 Mountain Standard Time
Direction of event from weather observation facility (degrees) 130
Weather Observation Facility ID BJC
Elevation of weather observation facility 5671
Distance of event from weather observation facility (units?) 13
Time Zone of the weather observation MST
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) 70
Air Temperature at event time (in degrees celsius) 15
Dew Point at event time (in degress fahrenheit) -3
Wind Direction (degrees magnetic) 0
Variable Wind Indicator Unknown
Wind Speed (knots) 0
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 30
Density Altitude (feet) 6592
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) 1534
NTSB Notification Source --
NTSB Notification Date Nov 2 1996 12:00AM
NTSB Notification Time 1418
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 8 2000 10:27AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N3616Z
NTSB Number FTW97FA033
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 1-36
Aircraft Series Identifier SGS 1-36
Aircraft Serial Number 9
Certified Max Gross Weight 710
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 Aug 1 1995 12:00AM
Airframe hours since last inspection 44
Airframe Hours 1742
ELT Installed No
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name RICHARD URBAN
Aircraft Owner Street Address 4143 SUNRISE CT.
Aircraft Owner City BOULDER
Aircraft Owner State CO
Aircraft Owner Country
Aircraft Owner Zipcode 80304
Operator is an individual? --
Operator Name THE CLOUD BASE
Operator Same as Owner? No
Operator Is Doing Business As --
Operator Address Same as Owner? No
Operator Street Address 5117 INDEPENDENCE RD.
Operator City BOULDER
Operator State CO
Operator Country
Operator Zip code 80301
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 1V5
Departure City
Departure State CO
Departure Country
Departure Time 1300
Departure Time Zone MST
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 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 --