Individually Owned: 150,657
Corporate Owned: 137,281
N/A Airport
Aircraft Accident/Incident Report
Avalon, Texas 76623
Tuesady, August 7, 2012 8:45 CDT
NTSB Narrative Summary Released at Completion of Accident
The helicopter was on its third test flight when the tail rotor 90-degree gearbox broke in two and separated from the helicopter. The crew conducted an autorotation to a field, and the helicopter came to rest on its side. Examination of the helicopter and components revealed that one of the tail rotor’s two counterweight bellcranks and associated hardware were missing. Impact marks consistent with a counterweight bellcrank were found at the base of its associated tail rotor blade and on the aft right side of the helicopter. The remaining counterweight bellcrank was in place; however, the cotter pin for the castellated nut was missing. A review of the aircraft maintenance records revealed that the tail rotor assembly had been removed and reinstalled after the installation of test instrumentation. The maintenance records lacked specific details on whether the unit and its components were previously handled as a subassembly or as individual components when the tail rotor assembly was initially removed. Because the records did not indicate whether the unit should be handled as individual parts, the tail rotor was reinstalled as a complete subassembly, meaning that individual components, such as the nut and cotter pin, were not individually inspected before or after reinstallation on the helicopter. Reinstalling the tail rotor assembly in this manner led to the counterweight bellcrank retaining nut not being properly torqued and secured with a cotter pin.
NTSB Probable Cause Narrative
Maintenance personnel’s failure to properly torque the retaining nut and install the cotter pin that secured the helicopter’s tail rotor counterweight bellcrank. Contributing to the accident was the lack of detailed maintenance records that documented previous maintenance actions.
Event Information
| Type of Event | Accident |
| Event Date | 8/7/2012 |
| Event Day of the Week | Tuesday |
| Time of Event | 845 |
| Event Time Zone | Central Daylight Time |
| Event City | Avalon |
| Event State | TEXAS |
| Event Country | -- |
| Zipcode of the event site | 76623 |
| Event Date Year | 2012 |
| Event Date Month | 8 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | 321626N |
| Event Location Longitude | 0964557W |
| Event Location Airport | N/A |
| 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 | Unknown |
| Time of the weather observation | 853 Central Standard Time |
| Direction of event from weather observation facility (degrees) | -- |
| Weather Observation Facility ID | KGKY |
| Elevation of weather observation facility | -- |
| Distance of event from weather observation facility (units?) | -- |
| Time Zone of the weather observation | CST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | -- |
| Lowest Non-Ceiling Height | -- |
| Sky/Lowest/Cloud Conditions | Clear |
| Sky Condition for Lowest Ceiling | -- |
| Visibility Runway Visual Range (Feet) | -- |
| Visibility Runway Visual Value (Statute Miles) | -- |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | 29 |
| Dew Point at event time (in degress fahrenheit) | 19 |
| Wind Direction (degrees magnetic) | -- |
| Variable Wind Indicator | Variable |
| Wind Speed (knots) | -- |
| Wind Velocity Indicator | Light and Variable |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | -- |
| Altimeter Setting at event time (in. Hg) | 29.97 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | -- |
| METAR weather report | KGKY 071353Z 00000KT 10SM CLR 29/19 A2997 RMK AO2 |
| 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 |
| NTSB Docket Number (internal use) | 32358 |
| NTSB Notification Source | ROC |
| NTSB Notification Date | -- |
| NTSB Notification Time | -- |
| Fiche Number and/or location -used to find docket information | -- |
| Date of most recent change to record | Jan 13 2014 12:35PM |
| User who most recently changed record | hatc |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N409SB |
| NTSB Number | CEN12LA525 |
| Missing Aircraft Indicator | -- |
| Federal Aviation Reg. Part | Part 91: General Aviation |
| Type of Flight Plan filed | Company VFR |
| Flight plan Was Activated? | -- |
| Damage | Substantial |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | BELL |
| Aircraft Model | 214ST |
| Aircraft Series Identifier | -- |
| Aircraft Serial Number | 28199 |
| Certified Max Gross Weight | -- |
| 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 | 18 |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Fixed |
| Aircraft, Type of Last Inspection | -- |
| Date of Last Inspection | -- |
| Airframe hours since last inspection | -- |
| Airframe Hours | -- |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | BELL HELICOPTER TEXTRON INC |
| Aircraft Owner Street Address | PO BOX 482 |
| Aircraft Owner City | FORT WORTH |
| Aircraft Owner State | TX |
| Aircraft Owner Country | USA |
| Aircraft Owner Zipcode | 76101-0482 |
| Operator is an individual? | No |
| Operator Name | BELL HELICOPTER TEXTRON INC |
| Operator Same as Owner? | Yes |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | Yes |
| Operator Street Address | PO BOX 482 |
| Operator City | FORT WORTH |
| Operator State | TX |
| Operator Country | USA |
| Operator Zip code | 76101-0482 |
| 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) | Flight Test |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | No |
| Departure Airport Code | KGKY |
| Departure City | Arlington Muni |
| Departure State | TX |
| Departure Country | USA |
| Departure Time | 815 |
| Departure Time Zone | CDT |
| Destination Same as Local Flt | dest & departure same, accident can occur anywhere |
| Destination Airport Code | KGKY |
| Destination City | Arlington Muni |
| Destination State | TX |
| Destination Country | USA |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Jan 13 2014 11:59AM |
| User who most recently changed record | hatc |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | N/A |
| Runway Length | -- |
| Runway Width | -- |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |