# NTSB FTW01LA214: Bell 206L-1, N1067D, W Cameron 168, September 26, 2001 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: September 26, 2001, 12:39 local (17:39 UTC) - Place: W Cameron 168 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report July 1, 2002 - Report: Approved by Office Director - Parties: Federal Aviation Administration, Air Logistics LLC - NTSB case key (mKey): 53544 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW01LA214 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/53544/pdf - Page: https://openairdocs.org/ntsb/FTW01LA214 ## Probable cause the failure of the rotor tachometer generator, which resulted in a precautionary landing in the Gulf of Mexico. A contributing factor to the accident was the rough water condition. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, approach - vfr pattern - base leg/base to final - misc rotorcraft,dual tachometer - failure,partial (cause) - precautionary landing - performed, pilot in command - On ground/water encounter with terrain/water, standing - terrain condition - water,rough (contributing factor) - rotor system,tail rotor - blade strike - rotor drive system,tail rotor drive shaft - separation ## Analysis The helicopter was on approach to an offshore platform, turning from base to final at 300 feet, when the pilot heard the low rotor rpm audio warning, and then noticed that the low rotor rpm warning light was illuminated. He initiated an autorotation and observed that the rotor rpm needle had dropped to zero. The pilot stated that as the helicopter was descending, he noticed feedback in the flight controls and decided that a precautionary landing was necessary. Subsequently, the pilot landed the helicopter in the water and shut down the engine. During the main rotor coast down, the tail rotor contacted a five foot wave, resulting in separation of the tail rotor drive shaft. The internal splines of the shaft and sleeve assembly of the rotor tachometer generator (part number 206-076-373-001) were found to be worn and not engaging. The failure of the rotor tachometer generator splines resulted in a loss of hydraulic pressure to the helicopter flight controls, since the hydraulic pump is driven by the rotor tachometer generator. ## Factual narrative On September 26, 2001, at 1239 central daylight time, a Bell 206L-1 helicopter, N1067D, was substantially damaged when its tail rotor contacted water while standing during main rotor coast down, following a precautionary landing in the Gulf of Mexico. The helicopter was owned and operated by Air Logistics LLC, of New Iberia, Louisiana. The commercial pilot and his two passengers were not injured. Visual meteorological conditions prevailed and a company visual flight rules flight plan was filed for the 14 Code of Federal Regulations Part 135 on-demand air taxi flight. The flight originated from Creole, Louisiana, at 1222, and was destined for West Cameron 168, an off-shore platform in the Gulf of Mexico. According to the pilot, the helicopter was approximately 100 feet from the destination platform, turning from base to final at 300 feet, when he heard the low rotor rpm audio warning, and then noticed that the low rotor rpm light was illuminated. He initiated an autorotation and observed that the rotor needle had dropped to zero. The pilot stated that as the helicopter was descending, he noticed "feedback" in the flight controls and "decided that a precautionary landing was necessary." Subsequently, the pilot landed the helicopter in the water and shut down the engine. According to the operator, "the #5 tail rotor drive shaft was broken during rotor coast down due to the tail rotor contacting a 5-foot wave on shut down." The pilot and two passengers were then rescued by emergency crews. Subsequently, the helicopter,. which remained afloat, was recovered and transported to the operator's maintenance facility for further examination. An FAA inspector and representatives from Air Logistics LLC examined the helicopter. They confirmed that the tail rotor drive shaft was separated. They discovered that the internal splines on the shaft and sleeve assembly of the Rotor Tachometer Generator (Globe Industries part number 206-076-373-001) were worn and not engaging. According to the FAA inspector, the output shaft from the main transmission oil pump drives the rotor tachometer generator, and the hydraulic pump is driven from the rotor tachometer generator. Therefore, if the rotor tachometer generator fails, the hydraulic pump also fails. The rotor tachometer generator is not time life limited, nor is there an inspection required for the unit. ## Aircraft - Registration: N1067D (not matched to a registry record) - Reported make and model: Bell 206L-1 - Category: Helicopter - Serial number: 45435 - Airframe hours: 22337.9 - Engines: Allison 250-C28B 395 horsepower turbo shaft - Damage: Substantial damage - Flight: Part 135 - Registered owner: Air Logistics LLC - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, August 18, 2001, 129.1 hours before - Departed: NONE, Creole, LA - Destination: W Cameron 168, GM - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 36; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: helicopter; medical: class 2, valid medical--no waivers/lim.; last flight review July 23, 2001; seat: right; flight hours: 3,117 total, 450 in this make and model, 1,901 as pilot in command, 268 in the last 90 days, 77 in the last 30 days, 4 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 75 °F ## 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 20010926033489A](https://openairdocs.org/incident/20010926033489A), Sep 26, 2001: Bell 206L1, Creole, LA, No damage. (-23) Following a successful auto rotation to the water due to nr low warning, the helicopter's tail rotor contacted the water before rotors could be stopped… 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.