# NTSB DFW06CA055: Bell 47-B3, N1575, Dennison, TX, January 13, 2006 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: January 13, 2006, 11:45 local (17:45 UTC) - Place: Dennison, TX - Coordinates: 33.71389, -96.674163 - Nearby events: https://openairdocs.org/map.md?lat=33.7139&lon=-96.6742&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report May 30, 2006 - Report: Approved by Office Director - Parties: Dallas Flight Standards District Office - NTSB case key (mKey): 63101 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DFW06CA055 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/63101/pdf - Page: https://openairdocs.org/ntsb/DFW06CA055 ## Probable cause The in-flight separation of the stabilizer bar tube. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Rotor failure/malfunction, maneuvering - rotor system,stabilizer bar - failure,partial - rotor system,stabilizer bar - separation (cause) - Forced landing, emergency descent/landing - autorotation - performed, pilot in command - On ground/water encounter with terrain/water, emergency landing - terrain condition - ground ## Analysis The 4,900-hour commercial pilot was maneuvering the single engine helicopter during a photo mission at approximately 1,500 feet mean sea level (MSL) at about 45 knots when he reported hearing a loud bang and a nearly simultaneous erratic movement of the cyclic control. The pilot immediately started looking for a place to land the helicopter. The pilot increased the airspeed and headed for a suitable landing area. On final approach to a vacant football field, the helicopter began to spin as the airspeed began to decay. The pilot then elected to enter an autorotation and landed upright with no further damage. The pilot and his passenger were not injured. An FAA inspector that traveled to the accident site reported that one stabilizer tube from the mast control stabilizer bar assembly had separated from the main rotor system and made the tail rotor assembly after it separated from the helicopter. Approximately 3 inches of one tail rotor blade was found fractured and the 90 degree tail rotor gear box separated from the tail rotor drive shaft. At the time of the accident the winds were reported from 360 degrees at 22 knots, gusting to 29 knots. ## Factual narrative The 4,900-hour commercial pilot was maneuvering the single engine helicopter during a photo mission at approximately 1,500 feet mean sea level (MSL) at about 45 knots when he reported hearing a loud bang and a nearly simultaneous erratic movement of the cyclic control. The pilot immediately started looking for a place to land the helicopter. The pilot increased the airspeed and headed for a suitable landing area. On final approach to a vacant football field, the helicopter began to spin as the airspeed began to decay. The pilot then elected to enter an autorotation and landed upright with no further damage. The pilot and his passenger were not injured. An FAA inspector that traveled to the accident site reported that one stabilizer tube from the mast control stabilizer bar assembly had separated from the main rotor system and made the tail rotor assembly after it separated from the helicopter. Approximately 3 inches of one tail rotor blade was found fractured and the 90 degree tail rotor gear box separated from the tail rotor drive shaft. At the time of the accident the winds were reported from 360 degrees at 22 knots, gusting to 29 knots. ## Aircraft - Registration: [N1575](https://openairdocs.org/deregistered/N1575-2018-02-08), registration cancelled 2018-02-08, S/N 57 (OpenAirDocs) - Reported make and model: Bell 47-B3 - Registry model: [Bell 47B3](https://openairdocs.org/model/bell-47b3) (registry code 1180606) (OpenAirDocs) - Registry engine: [Lycoming TVO-435-GIA](https://openairdocs.org/engine/lycoming-tvo-435-gia) (registry code 41526, turbo-prop) (OpenAirDocs) - Category: Helicopter - Serial number: 57 - Airframe hours: 11899 - Engines: Lycoming TVO-435 280 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Versatile Aviation - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, October 1, 2005, 20 hours before - Departed: GYI, Ardmore, OK - Destination: 1FO, Ardmore, OK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 52; injuries: none; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: airplane, helicopter; medical: class 2, without waivers/limitations; last flight review July 1, 2004; seat: left; flight hours: 4,900 total, 3,000 in this make and model, 4,800 as pilot in command, 150 in the last 90 days, 40 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 360° at 22 knots, gusting 29 - Visibility: 25 statute miles - Lowest ceiling: none - Temperature: 70 °F, dew point 10 °F - Altimeter: 30.02 inHg ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20060113000989A](https://openairdocs.org/incident/20060113000989A), Jan 13, 2006: Bell 47B3, Denison, TX, Substantial damage. (-23) Inspector [privacy data omitted] and I responded to an accident involving N1575, a Bell 47 helicopter in Denison Texas. We arrived to the scene at… ## Other investigations on N1575 (4) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB FTW01LA087](https://openairdocs.org/ntsb/FTW01LA087), Mar 22, 2001: Bell 47G2 (N1575), Ardmore, OK, substantial damage. Probable cause: the loss of tail rotor control during maneuvering resultant from the failure of the tail rotor drive shaft coupling due to a stripped thread which allowed the grease lubricating the shaft to leak… - [NTSB FTW98LA400](https://openairdocs.org/ntsb/FTW98LA400), Sep 17, 1998: Bell 47-G-2 (N1575), Ardmore, OK, substantial damage. Probable cause: The pilots failure to maintain clearance with terrain and the ensuing loss of control. - [NTSB CHI77FEC47](https://openairdocs.org/ntsb/CHI77FEC47), Sep 18, 1977: Bell 47B3 (N1575), Lake Orion, MI, substantial damage - [NTSB CHI70FDW10](https://openairdocs.org/ntsb/CHI70FDW10), Mar 27, 1970: Bell 47G (N1575), Port Huron, MI, substantial damage From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.