Pierre Municipal Airport
Aircraft Accident/Incident Report

Pierre, South Dakota 57501
Wednesday, September 25, 1991 13:30 CDT

NTSB Narrative Summary Released at Completion of Accident

THE ACCIDENT AIRPLANE WAS OBSERVED TO SUDDENLY ROLL INVERTED DURING FINAL APPROACH AND DESCEND INTO THE GROUND. INVESTIGATION OF THE WRECKAGE SHOWED A BENDING OVERLOAD FAILURE OF THE EXTERNAL THREADED STEM TYPE ROD END BEARING ATTACHED TO THE PISTON OF EACH WING FLAP HYDRAULIC ACTUATOR. THE EXPERIMENTAL RACING AIRPLANE WAS ORIGINALLY BUILT AND FLOWN WITHOUT WING FLAPS. THE WING FLAPS WERE ADDED BY THE PILOT/OPERATOR AT A LATER DATE.

NTSB Probable Cause Narrative

A BENDING OVERLOAD FAILURE OF THE WING FLAP CONTROL RODS AND REMEDIAL ACTION BY THE PILOT WAS NOT POSSIBLE. FACTORS IN THE ACCIDENT ARE THE INADEQUATE DESIGN OF THE WING FLAP SYSTEM BY THE PILOT/OPERATOR MANUFACTURER AND HIS LACK OF TOTAL EXPERIENCE IN TYPE OF AIRCRAFT.

Event Information

Type of Event Accident
Event Date 9/25/1991
Event Day of the Week Wednesday
Time of Event 1330
Event Time Zone Central Daylight Time
Event City PIERRE
Event State SOUTH DAKOTA
Event Country --
Zipcode of the event site 57501
Event Date Year 1991
Event Date Month 9
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude
Event Location Longitude
Event Location Airport PIERRE MUNICIPAL
Event Location Nearest Airport ID PIR
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 1742
Weather Briefing Completeness Unknown
Investigator's weather source Weather Observation Facility
Time of the weather observation 1332 Central Daylight Time
Direction of event from weather observation facility (degrees) 130
Weather Observation Facility ID PIR
Elevation of weather observation facility 1742
Distance of event from weather observation facility (units?) 1
Time Zone of the weather observation CDT
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 25000
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) 45
Air Temperature at event time (in degrees celsius) 20
Dew Point at event time (in degress fahrenheit) -2
Wind Direction (degrees magnetic) 310
Variable Wind Indicator Unknown
Wind Speed (knots) 20
Wind Velocity Indicator Unknown
Wind Gust Indicator Unknown
Wind Gust (knots) 28
Altimeter Setting at event time (in. Hg) 30
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 FAA
NTSB Docket Number (internal use) 2108
NTSB Notification Source --
NTSB Notification Date --
NTSB Notification Time 0
Fiche Number and/or location -used to find docket information 46798
Date of most recent change to record Dec 12 2000 10:44AM
User who most recently changed record dbo
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number NX39JR
NTSB Number CHI91DTK04
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 BOLAND/POE
Aircraft Model TSUNAMI
Aircraft Series Identifier TSUNAMI
Aircraft Serial Number 001
Certified Max Gross Weight 7500
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 Retractable
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Jan 2 2000 12:00AM
Airframe hours since last inspection --
Airframe Hours 200
ELT Installed No
ELT Activated Unknown
ELT Aided Location of Event Site Unknown
ELT Type --
Aircraft Owner Name JOHN RICHARD SANDBERG
Aircraft Owner Street Address 5475 N HWY 169
Aircraft Owner City PLYMOUTH
Aircraft Owner State MN
Aircraft Owner Country
Aircraft Owner Zipcode 55442
Operator is an individual? --
Operator Name JOHN RICHARD SANDBERG
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address 5475 N HWY 169
Operator City PLYMOUTH
Operator State MN
Operator Country
Operator Zip code 55442
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 CPR
Departure City CASPER
Departure State WY
Departure Country
Departure Time 1115
Departure Time Zone MDT
Destination Same as Local Flt crash at destination city
Destination Airport Code
Destination City
Destination State
Destination Country
Specific Phase of Flight Approach
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jan 2 2001 10:35AM
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 --