Grand Forks Intl Airport
Aircraft Accident/Incident Report

Grand Forks, North Dakota 58201
Friday, June 16, 2006 19:30 CDT

NTSB Narrative Summary Released at Completion of Accident

The helicopter was substantially damaged when the tail rotor struck the taxiway during recovery from an intentional autorotation. The flight instructor and commercial pilot (dual student) were not injured. The flight instructor stated that the instructional flight included 180-degree autorotations, which were terminated into a hover with the addition of engine power. He reported that on the first autorotation the dual student flared high and during the recovery the rotor speed decayed requiring a landing on the taxiway. He noted that the dual student was subsequently instructed to increase engine power as collective was increased during the recovery in order to maintain rotor speed. On the second autorotation, he stated that the dual student flared lower and a "little more aggressively." He noted that as the dual student increased the collective, the rotor speed again decayed. The flight instructor stated that "as the collective continued upward the engine and rotor [speed] decreased." He "intervened on the controls and continued to increase the collective and throttle and level the aircraft, [when] the tail struck the taxiway." The flight instructor subsequently landed the helicopter after noting an airframe vibration. The flight instructor reported no malfunctions or failures prior to the accident.

NTSB Probable Cause Narrative

The dual student's failure to maintain rotor speed during the recovery from the intentional autorotation and the flight instructor's delayed remedial action. Contributing factors were the flight crew's intentional autorotation and dual student's misjudged flare.

Event Information

Type of Event Accident
Event Date 6/16/2006
Event Day of the Week Friday
Time of Event 1930
Event Time Zone Central Daylight Time
Event City Grand Forks
Event Country --
Zipcode of the event site 58201
Event Date Year 2006
Event Date Month 6
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 475700N
Event Location Longitude 0971100W
Event Location Airport Grand Forks Intl
Event Location Nearest Airport ID GFK
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 --
Investigator's weather source Weather Observation Facility
Time of the weather observation 1953 Central Daylight Time
Direction of event from weather observation facility (degrees) --
Weather Observation Facility ID GFK
Elevation of weather observation facility 845
Distance of event from weather observation facility (units?) 0
Time Zone of the weather observation CDT
Lighting Conditions Day
Lowest Ceiling Height --
Lowest Non-Ceiling Height 25000
Sky/Lowest/Cloud Conditions Few
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 21
Dew Point at event time (in degress fahrenheit) 7
Wind Direction (degrees magnetic) 290
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) --
Wind Velocity Indicator --
Wind Gust Indicator Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 29.91
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report METAR KGFK 170053Z 29003KT 10SM FEW250 21/07 A2991
Event Highest Injury None
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor --
Injury Total None 2
Injury Total Serious --
Injury Total All --
Investigating Agency --
NTSB Docket Number (internal use) 20413
NTSB Notification Source FAA
NTSB Notification Date Jun 19 2006 12:00AM
NTSB Notification Time --
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Oct 3 2006 2:46PM
User who most recently changed record NTSB\JOHB
Basic weather conditions Visual Meteorological Cond
FAA District Office FAA-Fargo FSDO

Aircraft Involved

Aircraft #1

Aircraft Registration Number N1675U
NTSB Number CHI06CA168
Missing Aircraft Indicator --
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 Schweizer
Aircraft Model 269C
Aircraft Series Identifier --
Aircraft Serial Number S1878
Certified Max Gross Weight 2050
Aircraft Category Helicopter
Aircraft Registration Class --
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 2
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection May 1 2006 12:00AM
Airframe hours since last inspection --
Airframe Hours 480
ELT Installed No
ELT Activated No
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name Univ of North Dakota
Aircraft Owner Street Address --
Aircraft Owner City Grand Forks
Aircraft Owner State ND
Aircraft Owner Country USA
Aircraft Owner Zipcode --
Operator is an individual? Yes
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? --
Certified for Part 133 or 137 Operation --
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) Instructional
Second Pilot on Board Yes
Departure Point Same as Event Yes
Departure Airport Code GFK
Departure City Grand Forks
Departure State ND
Departure Country USA
Departure Time 1800
Departure Time Zone CDT
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 Landing - flare/touchdown
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Jul 21 2006 5:17PM
User who most recently changed record DINC
Since inspection or accident Time of Accident
Event Location Runway Number and Location NA
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --