# NTSB CEN14TA020: Bell OH-58A, N283MP, Jefferson City, MO, October 26, 2013 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Final report - Date: October 26, 2013, 13:00 local (18:00 UTC) - Place: Jefferson City, MO - Coordinates: 38.59111, -92.156112 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=38.5911&lon=-92.1561&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern downwind: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: Minor injuries - Injuries: 1 minor, 1 uninjured - Status: Completed, report April 23, 2014 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Bell Helicopter, Rolls-Royce Engines, Missouri State Highway Patrol - NTSB case key (mKey): 88320 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN14TA020 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/88320/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=88320 - Page: https://openairdocs.org/ntsb/CEN14TA020 ## Probable cause The loss of engine power for reasons that could not be determined because postaccident examinations of the engine did not reveal any anomalies that would have precluded normal operation. ## 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 OH-58A, 8 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=1181579), [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: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Bell OH-58A, 4 cases](https://openairdocs.org/ntsb-events/342/sequence.md?model=1181579), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Autorotation: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Bell OH-58A, 8 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=1181579), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis The pilot receiving instruction reported that the purpose of the flight was to remain in the airport traffic pattern while practicing autorotation landings. He stated that, after about 45 minutes of flight training, the engine began to fluctuate between full and half power while the helicopter was climbing on a downwind leg. The helicopter also experienced an uncommanded yaw with each engine power fluctuation. The flight instructor took control of the helicopter and entered a straight-in autorotation toward a nearby field. The helicopter touched down with a slight forward ground run, during which the left skid dug into the soft soil, which caused the helicopter to rotate 180 degrees before it stopped. The main rotor blades severed the tail boom from the fuselage during the forced landing. A postaccident examination revealed no airframe anomalies that would have prevented normal operation of the helicopter. During a test run, the accident engine demonstrated normal operation at all power settings and was capable of producing maximum takeoff horsepower. Uncontaminated fuel was found onboard the helicopter. The reason for the reported loss of engine power could not be determined. ## Factual narrative On October 26, 2013, at 1300 central daylight time, a Bell OH-58A helicopter, N283MP, was substantially damaged during a forced landing near the Jefferson City Memorial Airport (JEF), Jefferson City, Missouri. The pilot receiving instruction sustained minor injuries. The flight instructor was not injured. The public-use helicopter was registered to and operated by the Missouri State Highway Patrol, under the provisions of 14 Code of Federal Regulations Part 91, without a flight plan. Day visual meteorological conditions prevailed for the local area training flight that had departed JEF at 1215. The pilot receiving instruction reported that the purpose of the flight was to remain in the traffic pattern for runway 30 while practicing autorotation landings. He stated that after approximately 45 minutes of flight training, the engine began to fluctuate between full and half power while the helicopter was climbing on a downwind leg. The helicopter also experienced an uncommanded yaw with each engine power fluctuation. The flight instructor took control of the helicopter and entered a straight-in autorotation from an altitude of less than 1,000 feet above the ground. The pilot receiving instruction reported that the gas generator speed was less than 50 percent, the turbine temperature was about 300 degrees Celsius, and the main rotor speed was at 100 percent during the autorotation. The flight instructor began the landing flare about 50 above the ground and the helicopter touched down in a level attitude. However, shortly after touchdown, the helicopter rotated to the left after a landing skid dug into the soft terrain. The flight instructor reported that the helicopter experienced an intermittent left yawing motion that he associated with an interruption in engine power. Believing that a total loss of engine power was imminent, he took control of the helicopter and entered a straight-in autorotation toward a nearby open field. He stated that the helicopter touched down with a slight forward ground run, during which the left skid dug into the soft soil causing the helicopter to rotate 180-degrees before it came to a stop. The main rotor blades severed the tail boom from the fuselage during the forced landing. At 1253, the JEF automated surface observing system reported: wind from 270 degrees at 13 knots, gusting 17 knots, visibility 10 miles, sky clear, temperature 16 degrees Celsius, dew point 4 degrees Celsius, and an altimeter setting of 30.08 inches-of-mercury. A postaccident examination revealed no airframe or engine anomalies that would have prevented normal operation of the helicopter. The helicopter fuel system contained about 350 pounds of Jet-A fuel that was free of water and particulate contamination. The airframe fuel filter element was free of any particulate contamination. With electrical power applied, the airframe fuel boost pump functioned as designed and no leaks were identified throughout the fuel system. Engine control continuitywas established from the cockpit controls to the respective engine components. The engine magnetic chip detectors were clear of any metallic debris. No anomalies were identified with the engine's external air, fuel, and oil line connections. The engine fuel nozzle produced a normal spray pattern as the engine was rotated by the starter motor. The engine was removed from the airframe and shipped to the manufacturer for an operational test run. Before the engine test run, the pneumatic system was pressurized with shop air and no leaks were detected. The accident engine, a Rolls-Royce model T63-A-720, serial number AE 405896, was tested in accordance with the manufacturer's production specification. The engine demonstrated normal operation at all power settings and was capable of producing maximum takeoff horsepower. ## Aircraft - Registration: [N283MP](https://openairdocs.org/aircraft/N283MP), registered now, S/N 68-16918 (OpenAirDocs) - Reported make and model: BELL OH-58A - Registry model: [Bell OH-58A](https://openairdocs.org/model/bell-oh-58a) (registry code 1181579) (OpenAirDocs) - Category: Helicopter - Serial number: 68-16918 - Airframe hours: 5683 - Engines: Rolls-Royce T63-A-720 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Public aircraft - state, Public use - Operator: Missouri State Highway Patrol - Registered owner: Missouri State Highway Patrol - Airworthiness certificate: None - Last inspection: 100 hour, June 14, 2012, 80 hours before - Departed: JEF, Jefferson City, MO - Destination: JEF, Jefferson City, MO - Airport: JEF, Jefferson City Memorial ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 42; injuries: none; commercial, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review April 24, 2013; seat: left; restraint: 4-point; flight hours: 1,446 total, 96 in this make and model, 1,313 as pilot in command, 109 in the last 90 days, 30 in the last 30 days, 2 in the last 24 hours - Pilot; age 46; injuries: minor; flight instructor, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review July 26, 2013; seat: right; restraint: 4-point; flight hours: 5,403 total, 330 in this make and model, 5,233 as pilot in command, 66 in the last 90 days, 17 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 270° at 13 knots, gusting 17 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 61 °F, dew point 39 °F - Altimeter: 30.07 inHg - Turbulence: Unknown - Observed at: JEF, 1 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 20131026021419A](https://openairdocs.org/incident/20131026021419A), Oct 26, 2013: Bell OH-58A, Jefferson City, MO, Substantial damage. While climbing out on the downwind leg of runway 30, the engine began to surge. The instructor pilot immediately lowered the collective, rolled the throttle to… ## Docket (4 files) The files NTSB released with the investigation on January 31, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=88320. 1.4 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 256 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40408016&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Rolls-Royce Investigation Summary Report (item 2, .PDF, 77 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40408017&FileExtension=.PDF&FileName=Rolls-Royce%20Investigation%20Summary%20Report-Redacted.PDF - Statement of Party Representatives to NTSB Investigation (item 3, .PDF, 694 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40408018&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.PDF - Wreckage Release Documentation (item 4, .PDF, 406 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40408019&FileExtension=.PDF&FileName=Wreckage%20Release%20Documentation-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.