# NTSB CEN11LA356: Bell 206, N1815, Walton, KS, May 26, 2011 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: May 26, 2011, 14:23 local (19:23 UTC) - Place: Walton, KS - Coordinates: 38.153888, -97.285278 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.1539&lon=-97.2853&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-flare/touchdown: Abnormal runway contact](https://openairdocs.org/ntsb-events/090) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed, report February 12, 2013 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Rolls-Royce Corporation, FAA Wichita FSDO - NTSB case key (mKey): 79228 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN11LA356 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/79228/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=79228 - Page: https://openairdocs.org/ntsb/CEN11LA356 ## Probable cause A loss of engine power for undetermined reasons because postaccident examination of the airframe and engine revealed no anomalies. ## 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: [Bell Helicopter Textron 206L-1, 4 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=1182107), [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. - [Maneuvering: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342); cases with it: [Bell Helicopter Textron 206L-1, 3 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=1182107), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Autorotation: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Bell Helicopter Textron 206L-1, 2 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=1182107), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) - [Autorotation: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Bell Helicopter Textron 206L-1, 6 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=1182107), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-flare/touchdown: Abnormal runway contact](https://openairdocs.org/ntsb-events/090) (defining event); cases with it: [Bell Helicopter Textron 206L-1, 2 cases](https://openairdocs.org/ntsb-events/090/sequence.md?model=1182107), [All aircraft, 1,506 cases](https://openairdocs.org/ntsb-events/090/sequence.md) - [Landing-flare/touchdown: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Bell Helicopter Textron 206L-1, 1 case](https://openairdocs.org/ntsb-events/096/sequence.md?model=1182107), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md) - [Landing-flare/touchdown: Roll over](https://openairdocs.org/ntsb-events/097); cases with it: [Bell Helicopter Textron 206L-1, 3 cases](https://openairdocs.org/ntsb-events/097/sequence.md?model=1182107), [All aircraft, 261 cases](https://openairdocs.org/ntsb-events/097/sequence.md) - [Landing-flare/touchdown: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338); cases with it: [Bell Helicopter Textron 206L-1, 3 cases](https://openairdocs.org/ntsb-events/338/sequence.md?model=1182107), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) - [Post-impact: Evacuation](https://openairdocs.org/ntsb-events/460); cases with it: [Bell Helicopter Textron 206L-1, 1 case](https://openairdocs.org/ntsb-events/460/sequence.md?model=1182107), [All aircraft, 103 cases](https://openairdocs.org/ntsb-events/460/sequence.md) ## Analysis The pilot and flight mechanic were on a maintenance flight and had entered an autorotation to check the flat-pitch rotor speed, which was satisfactory. During recovery, about 500 feet above ground level, the pilot applied the throttle but the engine did not respond. The autorotational descent continued and the pilot executed a power-off running landing to a wheat field. As the helicopter touched down, a main rotor blade struck the tail boom, separating the tail boom at its attach point. Both main rotor blades impacted terrain and the helicopter came to rest on its right side. The pilot and flight mechanic were uncertain as to whether the engine had stopped running during the autorotation recovery or whether it was only operating at idle rpm. No preimpact anomalies were discovered that would have prevented normal operation. The engine was removed and run in a test cell, and the engine met specification power. The reason for the loss of engine power could not be determined. ## Factual narrative On May 26, 2011, at 1423 central daylight time, a Bell 206L-1, helicopter, N1815, was substantially damaged when it impacted terrain near Walton, Kansas. The helicopter was registered to GM Leasing Co., LLC, and operated by Air MD, LLC. Visual meteorological conditions prevailed and a company flight plan had been filed for the 14 Code of Federal Regulations Part 91 maintenance flight. The pilot and flight mechanic sustained minor injuries. The flight had originated from Newton City/County Airport (EWK), Newton, Kansas, at 1412 for a local flight. The pilot had entered an autorotation to check the flat-pitch rotor speed which was satisfactory. During recovery at about 500 feet above ground level (agl) the pilot rolled the throttle on but the engine did not respond. The autorotational descent continued and the helicopter was about 300 agl when the pilot heard a low rotor warning and observed the rotor rpm was about 80 percent. The pilot lowered the nose and executed a power-off running landing to a wheat field. As the helicopter touched down a main rotor blade struck the tail boom and the tail boom separated aft of the tail boom attach point. Both main rotor blades impacted terrain and the helicopter came to rest on its right side. The pilot and flight mechanic both reported that they were uncertain whether the engine had stopped running during the autorotation recovery or if it was only operating at idle rpm. Neither one of them remembered looking at the engine rpm gauge during the event nor did the pilot notice any annunciators other than the low rotor rpm annunciator. An examination of the helicopter found sufficient fuel on-board. Maintenance records did not show that any recent maintenance had been performed on the engine. No preimpact anomalies were discovered that would have prevented normal operation. The engine was removed and examined separately. The engine was placed in a test cell and two test runs were conducted. During the first test run the engine failed to meet specifications for take-off power by 2.4 percent and the engine anti ice valve was discovered stuck in the ON position. During the second test run the engine anti ice valve was removed and the engine met specification power for all test points. The reason for the loss of engine power could not be determined. ## Aircraft - Registration: [N1815](https://openairdocs.org/deregistered/N1815-2011-12-16), registration cancelled 2011-12-16, S/N 45299 (OpenAirDocs) - Reported make and model: BELL 206 (L1) - Registry model: [Bell Helicopter Textron 206L-1](https://openairdocs.org/model/bell-helicopter-textron-206l-1) (registry code 1182107) (OpenAirDocs) - Category: Helicopter - Serial number: 45299 - Airframe hours: 25443 - Engines: ALLISON 250 600 horsepower turbo shaft - Damage: Substantial damage - Flight: Other work use, Part 91 - Operator: Air Md LLC, doing business as Lifeteam - Registered owner: Gm Leasing Co LLC - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, May 15, 2011, 98 hours before - Departed: EWO, Newton, KS - Destination: EWO, Newton, KS - Flight plan: Company VFR - Airport: EWK, Newton City-County Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 60; injuries: minor; airline transport, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: helicopter, airplane; medical: class 1, with waivers/limitations; last flight review May 3, 2011; seat: right; flight hours: 16,365 total, 428 in this make and model, 13,233 as pilot in command, 34 in the last 90 days, 16 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 30° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 68 °F, dew point 43 °F - Altimeter: 30.01 inHg - Observed at: KEWK, 6 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 20110526013449A](https://openairdocs.org/incident/20110526013449A), May 26, 2011: Bell Helicopter Textron 206L-1, Walton, KS, Substantial damage. On may 26th, 2011, at approximately 1445 local time (1945 UTC), an airline transport pilot was involved in an aircraft accident while attempting to conduct a… ## Docket (10 files) The files NTSB released with the investigation on December 12, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=79228. 5.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 856 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383060&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - GPS 18 - Specialist's Factual Report of Investigation GPS (item 2, .PDF, 31 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383275&FileExtension=.PDF&FileName=GPS%2018%20-%20Specialist%27s%20Factual%20Report%20of%20Investigation%20GPS-Master.PDF - Maps (item 3, .PDF, 216 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383054&FileExtension=.PDF&FileName=Maps-Master.PDF - Weather Summary (item 4, .PDF, 29 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383055&FileExtension=.PDF&FileName=Weather%20Summary-Master.PDF - Photo 1 - View of Wreckage Looking Northwest (FAA Photo) (item 5, .PDF, 235 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383056&FileExtension=.PDF&FileName=Photo%201%20-%20View%20of%20Wreckage%20Looking%20Northwest%20%20(FAA%20Photo)-Master.PDF - Photo 2 - Wreckage As Viewed From The Front (FAA Photo) (item 6, .PDF, 340 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383057&FileExtension=.PDF&FileName=Photo%202%20-%20Wreckage%20As%20Viewed%20From%20The%20Front%20%20(FAA%20Photo)-Master.PDF - Photo 3 - Wreckage As Viewed From The Rear (FAA Photo) (item 7, .PDF, 642 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383058&FileExtension=.PDF&FileName=Photo%203%20-%20Wreckage%20As%20Viewed%20From%20The%20Rear%20%20(FAA%20Photo)-Master.PDF - Photo 4 - Detached Tail Boom and Tail Rotor Blades (FAA Photo) (item 8, .PDF, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383059&FileExtension=.PDF&FileName=Photo%204%20-%20Detached%20Tail%20Boom%20and%20Tail%20Rotor%20Blades%20%20(FAA%20Photo)-Master.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 9, .PDF, 228 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383061&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-Redacted.PDF - Reports from Parties to the Investigation - Rolls-Royce Engine Investigation Report (item 10, .PDF, 14 photos, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40383062&FileExtension=.PDF&FileName=Reports%20from%20Parties%20to%20the%20Investigation%20-%20Rolls-Royce%20Engine%20Investigation%20Report-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.