# NTSB WPR19LA019: Bell 47G, N1159W, Wichita Falls, TX, November 2, 2018 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Class 3 · Limited · Final report - Date: November 2, 2018, 11:30 local (16:30 UTC) - Place: Wichita Falls, TX - Coordinates: 33.941944, -98.602218 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.9419&lon=-98.6022&mi=10 - Phase of flight: [Emergency descent](https://openairdocs.org/ntsb-phases/600) (OpenAirDocs' grouping) - Defining event: [Autorotation: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Serious injuries - Injuries: 1 serious, 1 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 98599 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR19LA019 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/98599/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=98599 - Page: https://openairdocs.org/ntsb/WPR19LA019 ## Probable cause A total loss of engine power for reasons that could not be determined based on the available information. ## 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 47G-3B-1, 3 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=1181028), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) - [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Not specified (probable cause); cases with it: [Bell 47G-3B-1, 1 case](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=1181028), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Autorotation: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Bell 47G-3B-1, 5 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=1181028), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Autorotation: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Bell 47G-3B-1, 10 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=1181028), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Autorotation: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Bell 47G-3B-1, 2 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=1181028), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis The pilot reported that the purpose of the flight was to practice emergency procedures with a certified flight instructor (CFI). After completing four uneventful autorotations, they climbed the helicopter to an altitude of about 1,500 mean sea level and turned onto the final approach leg of the traffic pattern to conduct a ‘hydraulics off’ approach. Once established on final approach, the CFI reached down to turn off the hydraulic switch, and the engine lost complete power. The pilot immediately gave the flight controls to the CFI, and he prepared for an autorotation in a nearby field. During the descent, the helicopter impacted powerlines before it landed hard. The main rotor blade severed the tailboom, and the helicopter spun before it came to rest on its side. The CFI confirmed that when he reached down to turn off the hydraulic switch, the engine lost complete power. He mentioned that the hydraulic switch is on the lower console, and he was unaware of any nearby switches that would have turned off the engine. During a postaccident examination no anomalies were noted with the engine that would have precluded normal operations. The instrument panel was removed; the electrical wires were examined, and no abnormalities were noted. At the accident site, the ignition switch was found in the BOTH position. The ignition switch positions (RIGHT, LEFT, and BOTH) were tested and functioned normally. However, when the key was in the LEFT or RIGHT position, movement of the key would temporarily ground the switch. It was noted that a long keychain attached to the key extended over the hydraulics switch when the key was in the ignition. It is possible that the CFI moved the keychain away from the hydraulic switch and, in doing so, could have caused the ignition switch to temporarily ground. Subsequently, the engine would lose complete power with no warning. However, this scenario would require the ignition switch to be either in the LEFT or RIGHT position because moving the ignition key while in the BOTH position did not cause the switch to temporarily ground. Since there is no evidence of the switch being in a position other than BOTH, the investigation was unable to determine the reason for the total loss of engine power. ## Factual narrative On November 2, 2018, about 1130 central daylight time, a Bell 47G-3B-1, N1159W, was destroyed when it was involved in an accident in Wichita Falls, Texas. The pilot sustained minor injuries and the certified flight instructor sustained serious injuries. The helicopter was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. The pilot reported that the purpose of the flight was to practice emergency procedures with a certified flight instructor (CFI). After completing four uneventful autorotations, they climbed the helicopter to an altitude of about 1,500 mean sea level and turned onto the final approach leg of the traffic pattern to conduct a ‘hydraulics off’ approach. Once established on final approach, the CFI reached down to turn off the hydraulic switch and the engine lost complete power. The pilot immediately gave the flight controls to the CFI, and he prepared for an autorotation in a nearby field. During the descent, the helicopter impacted powerlines before it landed hard. The main rotor blade severed the tailboom, and the helicopter spun before it came to rest on its side. The CFI confirmed that when he reached down to turn off the hydraulic switch the engine lost complete power. There were no abnormal noises, nor were there any indications of an impending engine failure. The CFI mentioned that the hydraulic switch is on the lower console, and he was unaware of any nearby switches that would have turned off the engine. During a postaccident examination by a mechanic and a Federal Aviation Administration inspector, no anomalies were noted with the engine that would have precluded normal operations. The spark plugs were removed and consistent with normal operations. The engine rotated smoothly; the valves moved freely and evenly, thumb compression was established, and spark was obtained from the magnetos. The engine controls remained attached to the carburetor, the mixture was locked to the full rich position and the carburetor heat was in the OFF position. The carburetor was disassembled, and no anomalies were noted with the internal components. The fuel strainer was removed from the engine and the screen/bowl were clear of debris. The oil filter was also removed from the engine and was clear of debris. At the accident site, the ignition switch was found in the BOTH position. The instrument panel was removed, the electrical wires were examined, and no abnormalities were noted. The ignition switch positions (RIGHT, LEFT, and BOTH) were tested and functioned normally. However, when the key was in the LEFT or RIGHT position, a movement of the key would temporarily ground the switch. It was noted that a long keychain attached to the key extended over the hydraulics switch when the key was in the ignition. ## Aircraft - Registration: [N1159W](https://openairdocs.org/deregistered/N1159W-2021-12-04), registration cancelled 2021-12-04, S/N 2941, built 1964 (OpenAirDocs) - Reported make and model: Bell 47G (3B1) - Registry model: [Bell 47G-3B-1](https://openairdocs.org/model/bell-47g-3b-1) (registry code 1181028) (OpenAirDocs) - Registry engine: [Lycoming TVO-435-GIA](https://openairdocs.org/engine/lycoming-tvo-435-gia) (registry code 41526, turbo-prop) (OpenAirDocs) - Category: Helicopter - Serial number: 2941 - Year built: 1964 - Airframe hours: 6895 - Engines: Lycoming TV0-435 SERIE 270 horsepower reciprocating - Damage: Destroyed - Flight: Instructional, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 1, 2018, 27 hours before - Departed: F14, Wichita Falls, TX - Destination: F14, Wichita Falls, TX - Airport: F14, Wichita Valley Airport, runway 31, 3,320 × 40 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 83; injuries: serious; commercial, flight instructor; airplane ratings: single-engine land; instrument ratings: airplane, helicopter; medical: basicmed, with waivers/limitations; seat: right; restraint: lap only - Pilot; age 60; injuries: serious; flight engineer, commercial, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations; last flight review May 19, 2018; seat: left; restraint: lap only; flight hours: 14,961 total, 69 in this make and model, 3,000 as pilot in command, 57 in the last 90 days, 2 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 270° at 11 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 57 °F, dew point 41 °F - Altimeter: 30.05 inHg - Observed at: SPS, 7 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 20181102023229A](https://openairdocs.org/incident/20181102023229A), Nov 2, 2018: Bell 47G-3B-1, Iowa Park, TX, Destroyed. The pilot preflighted the helicopter on Friday morning before flying it 65 NM from his home to F14, about a 20 minute flight. He landed and meet with his CFI.… ## Other investigations on N1159W (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 MIA86LA152](https://openairdocs.org/ntsb/MIA86LA152), May 9, 1986: Bell 47G-3B-1 (N1159W), Panama City, FL, substantial damage - [NTSB ATL80DLA09](https://openairdocs.org/ntsb/ATL80DLA09), Aug 16, 1980: Bell 47G (N1159W), Blakely, GA, substantial damage ## Docket (5 files) The files NTSB released with the investigation on October 18, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=98599. 5.6 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 254 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=10061894&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Record of conversation - certified flight instructor (item 2, PDF, 1 page, 60 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=10067129&FileExtension=pdf&FileName=ROC%20CFI-Rel.pdf - Record of conversation - FAA inspector regarding airframe and engine examination (item 3, PDF, 5 pages, 626 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=11486587&FileExtension=pdf&FileName=ROC%20Examination-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 4, PDF, 1 page, 255 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=10062538&FileExtension=pdf&FileName=N1159W%20Wreckage%20Release%20signed_Redacted-Rel.pdf - On scene photos (item 5, PDF, 4 pages, 4.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=10067961&FileExtension=pdf&FileName=on%20scene%20photos-Rel.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.