# NTSB WPR10LA336: Johnson Helicycle, N62AJ, Arlington, WA, July 8, 2010 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: July 8, 2010, 13:05 local (20:05 UTC) - Place: Arlington, WA - Coordinates: 48.160556, -122.158889 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=48.1606&lon=-122.1589&mi=10 - Phase of flight: [Emergency descent](https://openairdocs.org/ntsb-phases/600) (OpenAirDocs' grouping) - Defining event: [Autorotation: Hard landing](https://openairdocs.org/ntsb-events/092) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report May 11, 2011 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 76553 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR10LA336 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/76553/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=76553 - Page: https://openairdocs.org/ntsb/WPR10LA336 ## Probable cause An undetermined airframe vibration which led to precautionary autorotation and hard landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Johnson Alden B HELICYCLE, 1 case](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=05621CW), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR pattern downwind: Miscellaneous/other](https://openairdocs.org/ntsb-events/900); cases with it: [Johnson Alden B HELICYCLE, 1 case](https://openairdocs.org/ntsb-events/900/sequence.md?model=05621CW), [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md) - [Autorotation: Hard landing](https://openairdocs.org/ntsb-events/092) (defining event); cases with it: [Johnson Alden B HELICYCLE, 1 case](https://openairdocs.org/ntsb-events/092/sequence.md?model=05621CW), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis The pilot reported that after an uneventful flight, he entered a left downwind traffic pattern for his intended landing area. As he lowered the collective to initiate a descent, he immediately experienced a severe vibration. The pilot stated that the vibration was so violent that it was impossible to read the cockpit instruments. He raised and lowered the collective and noted no change in the vibration. The pilot then initiated an autorotation to an open field adjacent to his intended landing area. The helicopter landed hard and came to rest upright. A postaccident examination of the helicopter revealed that the tail rotor was separated from the tail boom with additional damage observed to the fuselage and main rotor blades. Flight control continuity was established throughout the helicopter's flight control system. The source of the vibration could not be determined. ## Factual narrative On July 8, 2010, about 1305 Pacific daylight time, an amateur built experimental Johnson Helicycle helicopter, N62AJ, sustained substantial damage during a precautionary landing following an in-flight vibration while in the landing pattern at the Arlington Municipal Airport (AWO), Arlington, Washington. The helicopter was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91. The private pilot, sole occupant of the helicopter, sustained minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the local personal flight. The flight originated from AWO about 5 minutes prior to the accident. The pilot reported in a written statement that after an uneventful flight, he entered a left downwind for his intended landing area at AWO. As the pilot lowered the collective to initiate a descent, he immediately experienced a "severe violent" vibration. The pilot stated that the vibration seemed to be "consistent with a once-per-main-rotor-revolution vibration. The entire aircraft was shaking so violently that it was impossible to read any instruments." The pilot reported that he raised and lowered the collective and noted no change in the vibration. He initiated an auto rotation to an open field adjacent to his intended landing area. Subsequently, the helicopter landed hard and came to rest upright. Examination of the helicopter by the Safety Board investigator-in-charge revealed that the tail rotor was separated from the tail boom. Additional damage was observed to the fuselage, tail boom, and main rotor blades. Flight control was obtained throughout the helicopters flight control systems. The source of the vibration was undetermined. ## Aircraft - Registration: [N62AJ](https://openairdocs.org/aircraft/N62AJ), registered now, S/N 3-24 (OpenAirDocs) - Reported make and model: JOHNSON HELICYCLE - Registry model: [Johnson Alden B HELICYCLE](https://openairdocs.org/model/johnson-alden-b-helicycle) (registry code 05621CW) (OpenAirDocs) - Category: Helicopter, amateur-built - Serial number: 3-24 - Airframe hours: 123 - Engines: Solar T62 90 horsepower turbo shaft - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Johnson Alden B - Registered owner: Johnson Alden B - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Continuous airworthiness, June 4, 2010, 1 hours before - Departed: AWO, Arlington, WA - Destination: AWO, Arlington, WA - Airport: AWO, Arlington Municipal, runway 29, 3,498 × 75 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 68; injuries: minor; private; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 3, with waivers/limitations; last flight review April 21, 2009; seat: center; flight hours: 1,183 total, 109 in this make and model, 1,047 as pilot in command, 7 in the last 90 days, 4 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 290° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 84 °F - Observed at: AWO ## 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 20100708037459A](https://openairdocs.org/incident/20100708037459A), Jul 8, 2010: Johnson Ald HELICYCLE, Arlington, WA, Destroyed. On approch to land pilot experienced vibration in the seat, attempted to auto rotate, contacted the ground very hard, acusing the landing skids to fail. ## Docket (3 files) The files NTSB released with the investigation on January 14, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=76553. 1.3 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 340 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40341479&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 2, .PDF, 550 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40341482&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Redacted.PDF - Wreckage Examination Memo - Contains 1 Embedded Photo (item 3, .PDF, 425 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40341802&FileExtension=.PDF&FileName=Wreckage%20Examination%20Memo%20-%20Contains%201%20Embedded%20Photo-Master.PDF 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.