# NTSB LAX07LA173: Westland Helicopters Wasp HAS MK1, N612VH, Ramona, CA, May 25, 2007 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: May 24, 2007, 19:50 local (May 25, 2007, 02:50 UTC) - Place: Ramona, CA - Coordinates: 33.150833, -116.938056 - Nearby events: https://openairdocs.org/map.md?lat=33.1508&lon=-116.9381&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 3 minor, 1 uninjured - Status: Completed, report September 26, 2008 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 65901 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX07LA173 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/65901/pdf - Page: https://openairdocs.org/ntsb/LAX07LA173 ## Probable cause Failure of the pilot to maintain clearance from a tree while performing a precautionary landing. Contributing to the accident was the failure of a snubber dampener that induced a severe vibration in the rotor system. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, maneuvering - rotor system,main rotor hub lead-lag stop/damper - failure (contributing factor) - precautionary landing - attempted, pilot in command - In flight collision with object, emergency descent/landing - clearance - not maintained, pilot in command (cause) - object - tree(s) ## Analysis The pilot reported that during the flight a severe vibration began throughout the helicopter. The pilot was attempting to make a precautionary landing when the tail rotor stuck a tree. Maintenance personnel for the operator indicated that the vibration was due to a failure of one of the snubber dampeners on a main rotor blade. ## Factual narrative On May 24, 2007, about 1950 Pacific daylight time, the tail rotor of a Westland Helicopters Wasp HAS MK1, N612VH, struck a tree during a precautionary landing in a dirt field near Ramona, California. Classic Rotors Museum was operating the helicopter under the provisions of 14 Code of Federal Regulations (CFR) Part 91. The private pilot was not injured, and three passengers sustained minor injuries. The helicopter sustained substantial damage. The local personal flight departed Ramona Airport (RMN) about 1830. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot reported that during the flight he felt a severe vibration, and thought there might have been a hydraulic failure. He descended to a lower altitude and was attempting to land in a clearing. During the final portion of the landing, the controls were becoming harder to operate when the tail rotor struck the top of a tree. During the crash sequence, the tail rotor gearbox and tailboom departed the helicopter. After the helicopter was recovered, the National Transportation Safety Board investigator-in-charge (IIC) interviewed the pilot/mechanic for Classic Rotors Museum. He stated that although the damage to the rotor head and associated components were substantially destroyed during the accident sequence, he believes that one of the snubber dampners failed during the flight. He contacted maintenance personnel who were familiar with the accident make and model of helicopter, and they explained that if the snubber dampners failed it would result in the cyclic stirring. The pilot had experienced this prior to impacting the trees. ## Aircraft - Registration: [N612VH](https://openairdocs.org/aircraft/N612VH), registered now, S/N F87411, built 1969 (OpenAirDocs) - Reported make and model: Westland Helicopters Wasp HAS MK1 - Registry model: [Westland WASP HAS MK1](https://openairdocs.org/model/westland-wasp-has-mk1) (registry code 9640102) (OpenAirDocs) - Category: Helicopter - Serial number: F8-7411 - Airframe hours: 2911 - Engines: Rolls-Royce Nimbus 103 950 horsepower turbo shaft - Damage: Substantial damage - Flight: Flight test, Part 91 - Registered owner: Classic Rotors Museum - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Continuous airworthiness, September 1, 2006, 10 hours before - Departed: L39, RAMONA, CA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 50; injuries: none; private; medical: class 3, without waivers/limitations; last flight review June 1, 2006; seat: right; flight hours: 1,021 total, 11 in this make and model, 916 as pilot in command, 9 in the last 90 days, 7 in the last 30 days ## Weather - Conditions: Visual (VMC) - Wind: 250° at 6 knots - Visibility: 8 statute miles - Lowest ceiling: 1,200 ft overcast - Temperature: 61 °F, dew point 52 °F - Altimeter: 29.94 inHg - Observed at: CRQ, 17 nm away ## 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 20070524012969A](https://openairdocs.org/incident/20070524012969A), May 24, 2007: Westld WASPHASMK1, Ramona, CA, Substantial damage. (-23) The pilot stated that during cruise flight at about 200 feet and 100 knots, the cyclic control started to oscillate and became hard to operate. A… 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.