Individually Owned: 150,657
Corporate Owned: 137,281
Aircraft Accident/Incident Report
Chicago, Illinois 60601
Friday, June 30, 2006 12:00 CDT
NTSB Narrative Summary Released at Completion of Accident
The public-use helicopter was responding to an emergency when it had a vibration and yawed to the right during cruise flight. It subsequently had a loss of tail rotor thrust. The pilot reduced engine power and made an autorotation to a park along the lakeshore. During landing flare, the helicopter yawed left as the pilot increased collective prior to touchdown. He stated that the touchdown "seemed smooth" and was made on the aft-portion of the skids, but as the helicopter slowed the left yaw tendency increased. The helicopter rolled over and came to rest inverted at the completion of the run-on landing. Examination of the helicopter revealed that the number-one tail rotor driveshaft hanger assembly had separated, resulting in a discontinuity of the tail rotor driveshaft. The machine bolt that held the assembly together was not installed with the required cotter pin. Further examination of the hanger assembly revealed that the splined areas did not contain grease. The remaining tail rotor driveshaft hanger bearings were properly greased and assembled. The mechanic who worked on the helicopter reported that due to other workload items, the previous tail rotor driveshaft inspection was interrupted several times before he was able to complete all of the required tasks. To avoid inter-mixing the driveshaft components, he temporarily reassembled the hanger assemblies before working on other projects. His intention was to disassemble each hanger bearing when he had the opportunity to complete the inspection. The mechanic stated that he must have forgotten to disassemble, inspect, and grease the number one hanger assembly. At the time of the accident, the number one hanger assembly had accumulated about 33 hours since the inspection.
NTSB Probable Cause Narrative
The in-flight separation of a tail rotor driveshaft hanger bearing due to inadequate maintenance performed by maintenance personnel. Contributing to the accident was the inability to maintain directional control due to the lack of tail rotor thrust.
Event Information
| Type of Event | Accident |
| Event Date | 6/30/2006 |
| Event Day of the Week | Friday |
| Time of Event | 1200 |
| Event Time Zone | Central Daylight Time |
| Event City | Chicago |
| Event State | ILLINOIS |
| Event Country | -- |
| Zipcode of the event site | 60601 |
| Event Date Year | 2006 |
| Event Date Month | 6 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 414977N |
| Event Location Longitude | 0873612W |
| 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 | 1153 Central Daylight Time |
| Direction of event from weather observation facility (degrees) | 248 |
| Weather Observation Facility ID | MDW |
| Elevation of weather observation facility | 620 |
| Distance of event from weather observation facility (units?) | 7 |
| Time Zone of the weather observation | CDT |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | 12000 |
| 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) | 27 |
| Dew Point at event time (in degress fahrenheit) | 13 |
| Wind Direction (degrees magnetic) | 220 |
| Variable Wind Indicator | Wind direction could be determined |
| Wind Speed (knots) | 8 |
| Wind Velocity Indicator | -- |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 30.07 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | -- |
| Event Highest Injury | Minor |
| On Ground, Fatal Injuries | -- |
| On Ground, Minor Injuries | -- |
| On Ground, Serious Injuries | -- |
| Injury Total Fatal | -- |
| Injury Total Minor | 3 |
| Injury Total None | 1 |
| Injury Total Serious | -- |
| Injury Total All | 3 |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 23149 |
| NTSB Notification Source | Chicago Fire Dept |
| NTSB Notification Date | Jun 30 2006 12:00AM |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | DMS |
| Date of most recent change to record | Mar 31 2008 11:52AM |
| User who most recently changed record | NTSB\johb |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | Federal Aviation Administration - DuPage FSDO |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N681FD |
| NTSB Number | CHI06GA174 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Public Use |
| Type of Flight Plan filed | Company VFR |
| Flight plan Was Activated? | Yes |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Bell |
| Aircraft Model | UH-1H |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 65-10101 |
| Certified Max Gross Weight | 9500 |
| 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 | 8 |
| Number of Engines | 1 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | AAIP |
| Date of Last Inspection | Jun 1 2006 12:00AM |
| Airframe hours since last inspection | 6 |
| Airframe Hours | 5278 |
| ELT Installed | Yes |
| ELT Activated | Yes |
| ELT Aided Location of Event Site | No |
| ELT Type | -- |
| Aircraft Owner Name | City of Chicago Fire Department |
| Aircraft Owner Street Address | 3954 East Foreman Drive |
| Aircraft Owner City | Chicago |
| Aircraft Owner State | IL |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 60617 |
| 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 | Yes |
| Departure Point Same as Event | Yes |
| Departure Airport Code | LL35 |
| Departure City | Chicago |
| Departure State | IL |
| Departure Country | USA |
| Departure Time | 1150 |
| Departure Time Zone | CDT |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | LL35 |
| Destination City | Chicago |
| Destination State | IL |
| Destination Country | USA |
| Specific Phase of Flight | Emergency landing |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Feb 22 2008 6:05PM |
| 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 | -- |