# NTSB LAX02LA228: Schweizer 269C-1, N20256, Concord, CA, July 15, 2002 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 15, 2002, 14:57 local (21:57 UTC) - Place: Concord, CA - Coordinates: 37.989723, -122.056945 - Nearby events: https://openairdocs.org/map.md?lat=37.9897&lon=-122.0569&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report March 2, 2004 - Report: Approved by Office Director - Parties: Helicopter Adventures, Inc., Federal Aviation Administration, Schweizer Aircraft Corp. - NTSB case key (mKey): 55217 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX02LA228 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/55217/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=55217 - Page: https://openairdocs.org/ntsb/LAX02LA228 ## Probable cause The main rotor mast support tube failure as a result of fatigue. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, cruise - normal - rotor drive system,main rotor mast(drive shaft) - corroded (cause) - rotor drive system,main rotor mast(drive shaft) - fatigue (cause) - Forced landing, emergency descent/landing - autorotation - performed, pilot in command(cfi) ## Analysis The helicopter sustained an in-flight fracture and separation of the center aft mast support tube. While en route to the practice area, a slight vibration was felt through the airframe. Moments later, the vibration level became severe. The certified flight instructor (CFI) entered an autorotation, and during the descent, he looked back and found the tail rotor was disabled. The autorotation was completed to a field. Post accident metallurgical examination revealed a fracture surface consistent with fatigue. ## Factual narrative On July 15, 2002, at 1457 Pacific daylight time, a Schweizer 269C-1, N20256, sustained an in-flight fracture and separation of the center aft mast support tube about 10 miles east of Concord, California. The certified flight instructor (CFI) and the dual primary student were not injured; the helicopter sustained substantial damage. The helicopter was owned and operated by Helicopter Adventures, Inc., for a local area dual instructional flight under the provisions of 14 CFR Part 91. Visual meteorological conditions prevailed and no flight plan had been filed. In a written statement, the flight instructor reported that they were in level cruise flight en route to the practice area when a slight but unusual vibration was felt through the airframe. As he was reaching for the controls, the vibration level suddenly became severe. The left door departed the helicopter and the flight instructor entered an autorotation. During the descent, he looked back and found the tail rotor was disabled. The autorotation was completed to a field. A Federal Aviation Administration (FAA) airworthiness inspector examined the helicopter. He observed that the aft center mast support tube (p/n 269A2172-5) had fractured. He noted that a dark corrosion like appearance was present over a large part of the center of the fracture face. The part was painted with an epoxy coating and the inspector opined that this would have hindered visual detection of any crack in the underlying metal. He also reported that the tail rotor drive shaft had separated just aft of the oil cooler, and stated his belief that this was a secondary event to the vibration. The main rotor mast support tube was sent to the National Transportation Safety Board Materials Laboratory Division, Washington, D.C., for examination. The complete metallurgical examination report is in the docket for this accident. The examination revealed a fracture surface, relatively smooth and flat, in a plane perpendicular to the longitudinal axis. A region of the fracture had a reddish brown corrosion layer with smooth curving boundaries; a feature consistent with fatigue. Closer examination using scanning electron microscopy (SEM) of the fracture surface origin area, revealed three crack arrest lines and further corrosion. Scratches were also observed on the left side of the aft support tube in the paint at the lower edge and near the origin of the fracture surface. ## Aircraft - Registration: [N20256](https://openairdocs.org/deregistered/N20256-2013-10-29), registration cancelled 2013-10-29, S/N 0099, built 1999 (OpenAirDocs) - Reported make and model: Schweizer 269C-1 - Registry model: [Schweizer 269C-1](https://openairdocs.org/model/schweizer-269c-1) (registry code 8059504) (OpenAirDocs) - Registry engine: [Lycoming HO-360 series](https://openairdocs.org/engine/lycoming-ho-360-series) (registry code 41513, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 0099 - Airframe hours: 1609.6 - Engines: Textron Lycoming HO-360-CIA 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Registered owner: Helicopter Adventures, Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, June 19, 2002, 19.9 hours before - Departed: CCR, Concord, CA - Destination: CCR, Concord, CA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 23; injuries: none; commercial, flight instructor; instrument ratings: helicopter; medical: class 2, valid medical--w/ waivers/lim; last flight review March 16, 2002; seat: left; flight hours: 470 total, 420 in this make and model, 407 as pilot in command, 200 in the last 90 days, 50 in the last 30 days, 6 in the last 24 hours - Student pilot; injuries: none; seat: right; flight hours: 19 total ## Weather - Conditions: Visual (VMC), Day - Wind: 200° at 15 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 75 °F, dew point 32 °F - Altimeter: 29.90 inHg - Observed at: CCR, 10 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 20020715015649A](https://openairdocs.org/incident/20020715015649A), Jul 15, 2002: Hughes 269C1, Clayton, CA, No damage. (-23) Pilot russel reported in an interview the following events resulting in the forced emergency landing. On the day and time referenced, Mr. Russel as… ## Docket (8 files) The files NTSB released with the investigation on December 12, 2003, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=55217. 2.8 MB in all. - Materials Laboratory 15 - Factual Report 03-017 (item 1, .PDF, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40176240&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%2003-017-Master.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 2, .PDF, 500 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40461735&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Record of Conv FAA (item 3, .PDF, 20 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40187076&FileExtension=.PDF&FileName=Record%20of%20Conv%20FAA-Master.PDF - Record of Conv Pilot (item 4, .PDF, 29 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40187077&FileExtension=.PDF&FileName=Record%20of%20Conv%20Pilot-Master.PDF - Schwiezer Service Bulletin (item 5, .PDF, 93 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40187082&FileExtension=.PDF&FileName=Schwiezer%20Service%20Bulletin-Master.PDF - Schwiezer Failure Analysis (item 6, .PDF, 747 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40187084&FileExtension=.PDF&FileName=Schwiezer%20Failure%20Analysis-Master.PDF - Specialty Testing and Equipment Report (item 7, .PDF, 199 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40461736&FileExtension=.PDF&FileName=Specialty%20Testing%20and%20Equipment%20Report-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 8, .PDF, 53 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40461737&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-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.