# NTSB WPR11LA352: Eurocopter AS 350 B3, N808LF, Troutdale, OR, July 27, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 27, 2011, 15:40 local (22:40 UTC) - Place: Troutdale, OR - Coordinates: 45.549167, -122.399169 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=45.5492&lon=-122.3992&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) - Highest injury: No injuries - Injuries: 4 uninjured - Status: Completed, report April 20, 2012 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 81284 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR11LA352 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/81284/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=81284 - Page: https://openairdocs.org/ntsb/WPR11LA352 ## Probable cause The in-flight separation of the tail rotor drive shaft cover as a result of maintenance personnel not ensuring that it was secured after a maintenance inspection; also causal was the pilot’s inadequate preflight inspection of the helicopter. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Maintenance: scheduled/routine maintenance](https://openairdocs.org/ntsb-findings/02062010): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Eurocopter AS 350 B3, 2 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md?model=8680954), [All aircraft, 320 cases](https://openairdocs.org/ntsb-findings/02062010/cases.md) - [Inspection: preflight inspection](https://openairdocs.org/ntsb-findings/02061510): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Eurocopter AS 350 B3, 2 cases](https://openairdocs.org/ntsb-findings/02061510/cases.md?model=8680954), [All aircraft, 551 cases](https://openairdocs.org/ntsb-findings/02061510/cases.md) - [Fuselage: aerodynamic fairings structure](https://openairdocs.org/ntsb-findings/01035350): Aircraft › Aircraft structures · Incorrect service/maintenance (probable cause); cases with it: [Eurocopter AS 350 B3, 1 case](https://openairdocs.org/ntsb-findings/01035350/cases.md?model=8680954), [All aircraft, 5 cases](https://openairdocs.org/ntsb-findings/01035350/cases.md) - [Action: lack of action](https://openairdocs.org/ntsb-findings/02041030): Personnel issues › Action/decision · Maintenance personnel (probable cause); cases with it: [Eurocopter AS 350 B3, 3 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md?model=8680954), [All aircraft, 792 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft maintenance event](https://openairdocs.org/ntsb-events/040); cases with it: [Eurocopter AS 350 B3, 3 cases](https://openairdocs.org/ntsb-events/040/sequence.md?model=8680954), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md) - [Prior to flight: Aircraft inspection event](https://openairdocs.org/ntsb-events/050); cases with it: [Eurocopter AS 350 B3, 2 cases](https://openairdocs.org/ntsb-events/050/sequence.md?model=8680954), [All aircraft, 229 cases](https://openairdocs.org/ntsb-events/050/sequence.md) - [Enroute: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) (defining event); cases with it: [Eurocopter AS 350 B3, 2 cases](https://openairdocs.org/ntsb-events/338/sequence.md?model=8680954), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) ## Analysis The pilot reported that, about 12 minutes into a repositioning flight following a maintenance task performed by a company mechanic, he felt something that he described as similar to a bird strike. The pilot subsequently elected to make a precautionary landing in order to assess the situation. During an examination of the helicopter after the uneventful landing, the pilot discovered that a portion of the tail rotor drive shaft cover was missing and that one main rotor blade and two tail rotor blades had been damaged. Postaccident discussions with the company’s director of maintenance determined that the maintenance staff (who had recently performed a maintenance inspection) and the pilot likely looked at the tail rotor drive shaft cover prior to the accident flight and presumed that it was secure or had been secured by someone else; however, it was not secure and came off during flight. Following the accident, the company implemented a primary mechanic position into its Field Mechanic Procedures in order to mitigate a similar occurrence. ## Factual narrative On July 27, 2011, about 1540 Pacific daylight time, a Eurocopter AS 350 B3 helicopter, N808LF, sustained substantial damage after being struck by an object in cruise flight near Troutdale, Oregon. The commercial pilot and his five passengers were not injured. The helicopter was being operated by Air Methods Corporation of Englewood, Colorado. Visual meteorological conditions prevailed for the repositioning flight, which was being operated in accordance with 14 Code of Federal Regulations Part 91, and a flight plan was not filed. The flight departed the Aurora State Airport (UAO), Aurora, Oregon, about 1528, with Dallesport Airport (DLS), Dallesport, Washington, as its destination. In a report submitted to the National Transportation Safety Board investigator-in-charge (NTSB IIC), the Air Methods’ Aviation Compliance Manager stated that the aircraft departed from its maintenance facility at UAO to its normal base of operations located at DLS. The manager further stated that about 12 minutes into the flight the pilot reported that he felt something, like a bird strike, and elected to make a precautionary landing at TTD to inspect the helicopter for possible damage. Subsequent to an uneventful landing the pilot performed a walk-around inspection of the helicopter, during which it was discovered that a portion of the tail rotor drive shaft covering was missing. Upon further inspection of the helicopter, it was revealed that a single main rotor blade and two tail rotor blades had been damaged. In a statement provided to the IIC, the Air Methods’ Director of Maintenance (DOM) reported that as a result of his review of the maintenance that was performed on the helicopter prior to the accident flight, that all of the procedures for the 100-hour maintenance task were complied with, which included proper documentation of the work performed, including the required “Confirm Your Aircraft” (CYA) procedure, which was documented in the aircraft maintenance logbook. As provided to the IIC by Air Methods, the CYA requirements are as follows: • Any maintenance performed must be entered in the Air Methods’ Record of Maintenance. For all routine maintenance performed in the field by a company mechanic, a “Confirm Your Aircraft (CYA)” check will be performed. Whenever possible, a mechanic who did not sign off the maintenance action will perform the CYA. If a second mechanic is not available, a pilot will perform the check. • The CYA will include a thorough face-to-face briefing between the person who performed the work and the person performing the CYA. The person performing the CYA is required to do a general overview of the area in which the maintenance was performed. The person should look for disconnected lines, proper safeties (including safety wire, cotter pins, and lock tabs), oil or fuel, any cowlings/panels that were opened/removed, and any components/lines that were repositioned or removed in order to facilitate maintenance. • The CYA check shall beperformed before the aircraft is returned to service and will include at a minimum, a general overview for the following: o Loose or missing hardware in the area of maintenance. o Obvious defects in the area of maintenance. o Loose hardware or foreign objects left on the aircraft. The DOM reported that during post-accident discussions with the maintenance staff and the pilot, both felt that the [tail rotor drive shaft] cowling was secured. The DOM further reported that a possible scenario was that the maintenance staff and the pilot looked at the cowling prior to the ground runs and the accident flight and presumed that it was secure and that the work had been reviewed by someone else. The DOM revealed that in order to improve their Air Methods’ operations, the company had implemented a new policy designating a Primary Mechanic when more than one mechanic is working on a maintenance task. ## Aircraft - Registration: [N808LF](https://openairdocs.org/aircraft/N808LF), registered now, S/N 4983, built 2010 (OpenAirDocs) - Reported make and model: EUROCOPTER AS 350 B3 - Registry model: [Eurocopter AS 350 B3](https://openairdocs.org/model/eurocopter-as-350-b3) (registry code 8680954) (OpenAirDocs) - Registry engine: [Turbomeca ARRIEL-2B1](https://openairdocs.org/engine/turbomeca-arriel-2b1) (registry code 60056, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 4983 - Airframe hours: 282 - Engines: Turbomeca Arriel 2B1 653 horsepower turbo shaft - Damage: Substantial damage - Flight: Positioning, Part 91 - Operator: Air Methods - Registered owner: PNC Band NA Trustee - Airworthiness certificate: Standard, Normal - Last inspection: AAIP, July 27, 2011, 0 hours before - Departed: UAO, Aurora, OR - Destination: DLS, Dallesport, WA - Flight plan: Company VFR - Airport: TTD, Portland-Troutdale ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 38; injuries: none; commercial; instrument ratings: helicopter; medical: class 2, without waivers/limitations; last flight review January 24, 2011; seat: right; flight hours: 2,650 total, 339 in this make and model, 2,600 as pilot in command, 47 in the last 90 days, 18 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 75 °F, dew point 52 °F - Altimeter: 30.09 inHg - Observed at: TTD ## 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 20110727014929A](https://openairdocs.org/incident/20110727014929A), Jul 27, 2011: Eurocopter AS 350 B3, Troutdale, OR, Substantial damage. Aircraft departed aurora in route to the dalles approx. 15 minutes into flight the pilot heard a thump and aircraft started vibrating. The pilot decided a… ## Other investigations on N808LF (2) 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 WPR22LA154](https://openairdocs.org/ntsb/WPR22LA154), Apr 17, 2022: Eurocopter AS 350 B3 (N808LF), Deer Valley, AZ, substantial damage. Probable cause: The fuelers improper action during the refueling process. - [NTSB CEN14IA329](https://openairdocs.org/ntsb/CEN14IA329), Jun 26, 2014: Eurocopter AS 350 B3 (N808LF), Temple, TX, incident, minor damage. Probable cause: The pilot’s failure to reposition the yaw servo hydraulic switch to the “on” position during the pretakeoff hydraulic system check, which resulted in a complete lack of hydraulic boost to the tail… ## Docket (3 files) The files NTSB released with the investigation on March 15, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=81284. 1.6 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40363646&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Weather Data (item 2, .PDF, 60 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40363647&FileExtension=.PDF&FileName=Weather%20Data-Master.PDF - CYA Check Memo (item 3, .PDF, 161 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40364434&FileExtension=.PDF&FileName=CYA%20Check%20Memo-Redacted.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.