Aircraft Accident/Incident Report

Justice, Illinois 60458
Tuesady, July 26, 2005 10:10 CDT

NTSB Narrative Summary Released at Completion of Accident

The helicopter was destroyed when it impacted a sign, a privacy/guard fence, and the terrain adjacent to an interstate highway. The public use flight was conducted in order to survey a tollway. According to the pilot, the helicopter began, "a sudden right yaw with possibly a raising of the tail. The aircraft then yawed left, possibly in response to pedal input ... Then started what seemed to be a slower right rotation." The helicopter continued to rotate to the right, descended, and impacted the structure of an overhead road sign, a privacy/guard fence and then came to rest on the ground adjacent to the fence. The reported winds in the vicinity of the accident site were 290 degrees at 15 knots. Radar track data showed that the helicopter traveled in a northwesterly direction parallel to an interstate highway, passed a toll plaza, and then began a left turn. The radar data showed that during the left turn, the wind direction relative to the aircraft ground track entered the region defined in the Federal Aviation Administration "Rotorcraft Flying Handbook" (FAA-H-8083-21), as being conducive to weathercock instability. During this same period, the helicopter's calibrated airspeed was between 4 and 20 knots. FAA-H-8083-21 states that, "In this region, the helicopter attempts to weathervane its nose into the relative wind. Unless a resisting pedal input is made, the helicopter starts a slow, uncommanded turn either to the right or left depending upon the wind direction. If the pilot allows a right yaw rate to develop and the tail of the helicopter moves into this region, the yaw rate can accelerate rapidly." FAA-H-8083-21 also states that, "Unanticipated yaw is the occurrence of an uncommanded yaw rate that does not subside of its own accord and, which, if not corrected, can result in the loss of helicopter control. This uncommanded yaw rate is referred to as loss of tail rotor effectiveness (LTE) and occurs to the right in helicopters with a counter-clockwise rotating main rotor." No anomalies were found with respect to the helicopter.

NTSB Probable Cause Narrative

The pilot's improper in-flight decision while maneuvering which resulted in a tailwind during low airspeed helicopter flight and subsequent loss of tail rotor effectiveness. The struck sign and fence were factors in the accident.

Event Information

Type of Event Accident
Event Date 7/26/2005
Event Day of the Week Tuesday
Time of Event 1010
Event Time Zone Central Daylight Time
Event City Justice
Event State ILLINOIS
Event Country --
Zipcode of the event site 60458
Event Date Year 2005
Event Date Month 7
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude 414460N
Event Location Longitude 0875007W
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 --
Investigator's weather source Weather Observation Facility
Time of the weather observation 1453 Central Daylight Time
Direction of event from weather observation facility (degrees) 55
Weather Observation Facility ID MDW
Elevation of weather observation facility 620
Distance of event from weather observation facility (units?) 5
Time Zone of the weather observation CDT
Lighting Conditions Day
Lowest Ceiling Height 3000
Lowest Non-Ceiling Height --
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling Broken
Visibility Runway Visual Range (Feet) --
Visibility Runway Visual Value (Statute Miles) --
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 28
Dew Point at event time (in degress fahrenheit) 20
Wind Direction (degrees magnetic) 290
Variable Wind Indicator Wind direction could be determined
Wind Speed (knots) 15
Wind Velocity Indicator --
Wind Gust Indicator Not Gusting
Wind Gust (knots) --
Altimeter Setting at event time (in. Hg) 29.79
Density Altitude (feet) --
Intensity of Precipitation --
METAR weather report METAR KMDW 261353Z 27010G19KT 10SM FEW031 SCT049 B
Event Highest Injury Serious
On Ground, Fatal Injuries --
On Ground, Minor Injuries --
On Ground, Serious Injuries --
Injury Total Fatal --
Injury Total Minor 2
Injury Total None --
Injury Total Serious 2
Injury Total All 4
Investigating Agency NTSB
NTSB Docket Number (internal use) 20715
NTSB Notification Source FAA
NTSB Notification Date Jul 26 2005 12:00AM
NTSB Notification Time --
Fiche Number and/or location -used to find docket information DMS
Date of most recent change to record Dec 28 2006 9:08AM
User who most recently changed record NTSB\johb
Basic weather conditions Visual Meteorological Cond
FAA District Office Dupage FSDO

Aircraft Involved

Aircraft #1

Aircraft Registration Number N741LL
NTSB Number CHI05GA198
Missing Aircraft Indicator --
Federal Aviation Reg. Part Public Use
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Destroyed
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Bell
Aircraft Model 206L-3
Aircraft Series Identifier --
Aircraft Serial Number 51165
Certified Max Gross Weight 4150
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 6
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection May 1 2005 12:00AM
Airframe hours since last inspection 88
Airframe Hours 8026
ELT Installed Yes
ELT Activated Yes
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name Illinois Department of Transportation
Aircraft Owner Street Address 1 Lang Horne Bond Dr.
Aircraft Owner City Springfield
Aircraft Owner State IL
Aircraft Owner Country USA
Aircraft Owner Zipcode 62707
Operator is an individual? No
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) --
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code --
Departure City Downers Grove
Departure State IL
Departure Country USA
Departure Time 910
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 Maneuvering
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Oct 13 2006 11:27AM
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 --