Aircraft Accident/Incident Report

Boulder, Colorado 80301
Friday, July 16, 1993 13:30 MDT

NTSB Narrative Summary Released at Completion of Accident

ACCORDING TO THE PILOT, DURING INITIAL CLIMB FOLLOWING TAKEOFF, WHILE UNDER TOW ON A GLIDER FLIGHT, THE SPOILERS DEPLOYED AND COULD NOT BE RETRACTED. THE PILOT RELEASED FROM THE TOW AND ATTEMPTED TO RETURN TO THE AIRPORT. THE GLIDER IMPACTED IN A FIELD APPROXIMATELY 1/2 MILE SHORT OF THE RUNWAY. THE PILOT STATED THAT THE SPOILERS HAD BEEN MISRIGGED.

NTSB Probable Cause Narrative

IMPROPER RIGGING OF THE SPOILER SYSTEM BY MAINTENANCE PERSONNEL, WHICH CAUSED AN UNCOMMANDED SPOILER DEPLOYMENT AND PREVENTED SPOILER RETRACTION BY THE PILOT. A FACTOR WAS UNSUITABLE TERRAIN FOR A FORCED LANDING

Event Information

Type of Event Accident
Event Date 7/16/1993
Event Day of the Week Friday
Time of Event 1330
Event Time Zone Mountain Daylight Time
Event City BOULDER
Event State COLORADO
Event Country --
Zipcode of the event site 80301
Event Date Year 1993
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 Not pertinent
Investigator's weather source Weather Observation Facility
Time of the weather observation 1252 Mountain Daylight Time
Direction of event from weather observation facility (degrees) 150
Weather Observation Facility ID BJC
Elevation of weather observation facility 5657
Distance of event from weather observation facility (units?) 10
Time Zone of the weather observation MDT
Lighting Conditions Day
Lowest Ceiling Height 20000
Lowest Non-Ceiling Height 8000
Sky/Lowest/Cloud Conditions Scattered
Sky Condition for Lowest Ceiling Broken
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 75
Air Temperature at event time (in degrees celsius) 29
Dew Point at event time (in degress fahrenheit) 14
Wind Direction (degrees magnetic) 10
Variable Wind Indicator Unknown
Wind Speed (knots) 6
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29
Density Altitude (feet) 8500
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Minor
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor 1
Injury Total None --
Injury Total Serious --
Injury Total All 1
Investigating Agency NTSB
NTSB Docket Number (internal use) 979
NTSB Notification Source --
NTSB Notification Date Jul 16 1993 12:00AM
NTSB Notification Time 1816
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Dec 11 2000 1:28PM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N4362
NTSB Number DEN93LA080
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name GLASFLUGEL
Aircraft Model STANDARD LIBELL
Aircraft Series Identifier STANDARD L
Aircraft Serial Number 216
Certified Max Gross Weight --
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 --
Number of Engines 0
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Apr 16 1993 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 VALAS, HARRY R.
Aircraft Owner Street Address 122 S. JERSEY STREET
Aircraft Owner City DENVER
Aircraft Owner State CO
Aircraft Owner Country
Aircraft Owner Zipcode 80226
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
Departure City
Departure State
Departure Country
Departure Time 1330
Departure Time Zone MDT
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 Takeoff
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 --