# NTSB CEN13LA378: Bell 206B, N297CA, St Louis, MO, May 24, 2013 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 23, 2013, 21:00 local (May 24, 2013, 02:00 UTC) - Place: St Louis, MO - Coordinates: 38.75111, -90.371391 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.7511&lon=-90.3714&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering: Uncontained engine failure](https://openairdocs.org/ntsb-events/343) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report December 15, 2014 - Report: Approved by Office Director - NTSB office: Central Region - Parties: NTSB - Materials Lab, NTSB - Engineering, FAA FSDO - NTSB case key (mKey): 86992 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN13LA378 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/86992/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=86992 - Page: https://openairdocs.org/ntsb/CEN13LA378 ## Probable cause The loss of engine power due to the separation of compressor blades, which resulted from fatigue cracking. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (turbine/turboprop): compressor section](https://openairdocs.org/ntsb-findings/01057230): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Bell 206B, 2 cases](https://openairdocs.org/ntsb-findings/01057230/cases.md?model=1181511), [All aircraft, 53 cases](https://openairdocs.org/ntsb-findings/01057230/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering: Uncontained engine failure](https://openairdocs.org/ntsb-events/343) (defining event); cases with it: [Bell 206B, 1 case](https://openairdocs.org/ntsb-events/343/sequence.md?model=1181511), [All aircraft, 47 cases](https://openairdocs.org/ntsb-events/343/sequence.md) - [Maneuvering: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341); cases with it: [Bell 206B, 17 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=1181511), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Maneuvering: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Bell 206B, 21 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=1181511), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis The flight instructor reported that, shortly after he and the pilot-rated student departed on a night training flight in the turbine-powered helicopter, they heard a loud bang, and the helicopter yawed left. The flight instructor chose to perform an autorotation with forward airspeed onto the airport's taxiway. Examination of the turbine engine revealed several holes in the compressor case, consistent with engine blades exiting the engine. Further examination revealed that the stages 3 through 6 compressor blades had separated at the roots. Examination also revealed that the 3rd-stage wheel blade root had fractured due to progressive cracking, consistent with fatigue; 54 percent of the fracture surface exhibited fatigue features. However, the fracture initiation surface was destroyed, so it was not possible to determine the cause of the fatigue failure. Indications of fatigue were also found on the stages 3 through 6 blades' fracture surfaces. The engine's compressor had 13,874 hours time since new (TSN) and the compressor rotor stages 1 through 6 wheels had 1,185.3 hours TSN and were Parts Manufacturer Approval replacement parts. ## Factual narrative On May 23, 2013, about 2100 central daylight time, a Bell 206B helicopter, N297CA performed an autorotation to a forced landing at the Spirit of St. Louis Airport (KSUS), St. Louis, Missouri. The flight instructor and commercial rated pilot were not injured and the helicopter was substantially damaged. The helicopter was registered to GM Leasing Co., LLC and operated by Air-Evac Lifeteam, O'Fallon, Missouri, under the provisions of 14 Code of Federal Regulations Part 91 as a training flight. Night visual meteorological conditions prevailed for the flight that operated on a company flight plan. The flight instructor reported that he was demonstrating a normal takeoff. As the helicopter accelerated to about 50 knots and was 20 feet in altitude, there was a loud bang. The helicopter yawed left, and then the instructor elected to perform an autorotation landing with forward airspeed on the taxiway. During an initial visual inspection of the airframe, no observable damage was noted. Inspection of the engine, revealed a case breach on the axial compressor. Further examination of the helicopter's airframe revealed substantial damage to the aft fuselage and main rotor system.A review of the helicopter's Rolls-Royce 250-C20B engine maintenance records, revealed that the engine had 15,179.6 hours TSN (time since new) and 4,948 cycles TSN. The engine's compressor had 13,874 hours (TSN) and the compressor rotor stage 1-6 wheels had 1,185.3 hours (TSN) and were Parts Manufacturer Approval (PMA) replacement parts. The examination of the engine revealed several areas where the compressor case had been breached by fragments exiting the engine. Further examination of the stage 1 compressor blades revealed the blades were in place and in good condition. The stage two blades were present, but exhibited varying degrees of trailing edge damage. All stage 3 through 6 blades had separated at the blade root. The 3, 4, and 6 compressor stator vanes were completely separated and ingested. Stage 2 and 5 vanes were present, but bent and/or torn in the direction of rotation. The compressor impeller was intact, but had leading edge damage 360-degrees around the disk. Several impeller blades exhibited blade tip bending, consistent with debris ingestion. The axial compressor rotor and stator was sent to the National Transportation Safety Board (NTSB) materials lab, in Washington, D.C. Examination of the 3rd stage wheel found a blade root that had about a 54% progressive cracking area, consistent with fatigue. The examination also found indications of fatigue on stage 3 through 6 blades. ## Aircraft - Registration: [N297CA](https://openairdocs.org/aircraft/N297CA), registered now, S/N 1453, built 1974 (OpenAirDocs) - Reported make and model: BELL 206B - Registry model: [Bell 206B](https://openairdocs.org/model/bell-206b) (registry code 1181511) (OpenAirDocs) - Registry engine: [Rolls-Royce 250-C20B](https://openairdocs.org/engine/rolls-royce-250-c20b) (registry code 54385, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 1453 - Airframe hours: 15025 - Engines: ROLLS-ROYCE 250-C20B 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Air-Evac Lifeteam - Registered owner: Gm Leasing Co LLC - Airworthiness certificate: Unknown - Last inspection: Annual, May 14, 2013 - Departed: KSUS, St Louis, MO - Destination: KSUS, St Louis, MO - Flight plan: Company VFR - Airport: KSUS, Spirit of St. Louis Airport ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 51; injuries: none; commercial; airplane ratings: single-engine land; instrument ratings: helicopter; medical: class 2, without waivers/limitations; last flight review November 2, 2012; seat: right; restraint: 3-point; flight hours: 6,895 total, 5,536 in this make and model, 6,744 as pilot in command, 63 in the last 90 days, 18 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Night - Wind: 80° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 57 °F, dew point 52 °F - Altimeter: 30.21 inHg - Observed at: KSUS ## 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 20130523011509A](https://openairdocs.org/incident/20130523011509A), May 23, 2013: Bell 206B, Chesterfield, MO, Substantial damage. On may 23, 2013 at approximately 2100 hrs. The flight instructor was acting as the pilot in command of helicopter N297CA, a Bell helicopter BHT-206B, s/n 1453.… ## Other investigations on N297CA (1) 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 CEN26LA264](https://openairdocs.org/ntsb/CEN26LA264), Jul 17, 2026: Bell 206B (N297CA), Saint Joseph, IL, substantial damage, investigation ongoing ## Docket (4 files) The files NTSB released with the investigation on November 10, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=86992. 47.4 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 857 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418797&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Materials Lab Factual Report (item 2, .PDF, 46.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418799&FileExtension=.PDF&FileName=Materials%20Lab%20Factual%20Report-Master.PDF - Weather Report (item 3, .PDF, 13 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418800&FileExtension=.PDF&FileName=Weather%20Report-Master.PDF - Release of Aircraft Wreckage, NTSB Form 6120.15 (item 4, .PDF, 152 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40418798&FileExtension=.PDF&FileName=Release%20of%20Aircraft%20Wreckage,%20NTSB%20Form%206120.15-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.