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Location:
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Wichita Falls, Texas
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Accident Number:
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WPR19LA019
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Date & Time:
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November 2, 2018, 11:30 Local
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Registration:
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N1159W
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Aircraft:
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Bell 47G
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Aircraft Damage:
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Destroyed
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Defining Event:
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Loss of engine power (total)
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Injuries:
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1 Serious, 1 Minor
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Flight Conducted Under: Part 91: General aviation - Instructional
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.
Probable Cause and Findings
The National Transportation Safety Board determines the probable cause(s) of this accident to be: A total loss of engine power for reasons that could not be determined based on the available information.
Findings
Not determined: (general) - Unknown/Not determined
Aircraft: Not specified
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Factual Information
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.
History of Flight
Autorotation: Loss of engine power (total) (Defining event)
Autorotation: Collision with terr/obj (non-CFIT)
Autorotation: Hard landing
Flight instructor Information
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Certificate:
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Commercial; Flight instructor
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Age:
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83,Male
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Airplane Rating(s):
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Single-engine land
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Seat Occupied:
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Right
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Other Aircraft Rating(s):
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Helicopter
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Restraint Used:
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Lap only
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Instrument Rating(s):
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Airplane; Helicopter
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Second Pilot Present:
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Yes
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Instructor Rating(s):
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Helicopter
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Toxicology Performed:
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No
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Medical Certification:
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BasicMed With waivers/limitations
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Last FAA Medical Exam:
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November 28, 2017
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Occupational Pilot:
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No
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Last Flight Review or Equivalent:
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Flight Time:
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Pilot Information
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Certificate:
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Airline transport; Commercial; Flight engineer
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Age:
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60,Male
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Airplane Rating(s):
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Single-engine land; Multi-engine land
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Seat Occupied:
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Left
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Other Aircraft Rating(s):
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Helicopter
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Restraint Used:
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Lap only
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Instrument Rating(s):
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Airplane
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Second Pilot Present:
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Yes
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Instructor Rating(s):
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None
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Toxicology Performed:
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No
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Medical Certification:
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Class 1 With waivers/limitations
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Last FAA Medical Exam:
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June 26, 2018
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Occupational Pilot:
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Yes
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Last Flight Review or Equivalent:
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May 19, 2018
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Flight Time:
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14961 hours (Total, all aircraft), 69 hours (Total, this make and model), 3000 hours (Pilot In Command, all aircraft), 57 hours (Last 90 days, all aircraft), 2 hours (Last 30 days, all aircraft), 0 hours (Last 24 hours, all aircraft)
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Aircraft and Owner/Operator Information
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Aircraft Make:
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Bell
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Registration:
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N1159W
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Model/Series:
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47G 3B1
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Aircraft Category:
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Helicopter
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Year of Manufacture:
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1964
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Amateur Built:
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Airworthiness Certificate:
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Normal
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Serial Number:
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2941
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Landing Gear Type:
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Skid
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Seats:
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3
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Date/Type of Last Inspection:
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May 1, 2018 Annual
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Certified Max Gross Wt.:
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2850 lbs
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Time Since Last Inspection:
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27 Hrs
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Engines:
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1 Reciprocating
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Airframe Total Time:
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6895 Hrs at time of accident
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Engine Manufacturer:
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Lycoming
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ELT:
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Not installed
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Engine Model/Series:
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TV0-435 SERIE
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Registered Owner:
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Rated Power:
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270 Horsepower
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Operator:
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On file
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Operating Certificate(s) Held:
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None
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Meteorological Information and Flight Plan
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Conditions at Accident Site:
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Visual (VMC)
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Condition of Light:
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Day
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Observation Facility, Elevation:
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SPS,1019 ft msl
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Distance from Accident Site:
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7 Nautical Miles
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Observation Time:
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10:52 Local
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Direction from Accident Site:
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69°
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Lowest Cloud Condition:
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Clear
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Visibility
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10 miles
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Lowest Ceiling:
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None
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Visibility (RVR):
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Wind Speed/Gusts:
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11 knots /
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Turbulence Type Forecast/Actual:
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None / None
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Wind Direction:
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270°
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Turbulence Severity Forecast/Actual:
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N/A / N/A
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Altimeter Setting:
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30.05 inches Hg
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Temperature/Dew Point:
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14°C / 5°C
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Precipitation and Obscuration:
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No Obscuration; No Precipitation
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Departure Point:
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Wichita Falls, TX (F14 )
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Type of Flight Plan Filed:
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None
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Destination:
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Wichita Falls, TX (F14 )
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Type of Clearance:
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None
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Departure Time:
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11:05 Local
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Type of Airspace:
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Unknown
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Airport Information
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Airport:
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Wichita Valley
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Airport
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F14
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Runway Surface Type:
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Asphalt
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Airport Elevation:
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1005 ft msl
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Runway Surface Condition:
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Dry;Vegetation
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Runway Used:
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31
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IFR Approach:
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None
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Runway Length/Width:
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3320 ft / 40 ft
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VFR Approach/Landing:
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Forced landing;Simulated forced landing;Straight-in
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Wreckage and Impact Information
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Crew Injuries:
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1 Serious, 1 Minor
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Aircraft Damage:
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Destroyed
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Passenger Injuries:
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Aircraft Fire:
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None
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Ground Injuries:
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N/A
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Aircraft Explosion:
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None
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Total Injuries:
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1 Serious, 1 Minor
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Latitude, Longitude:
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33.941944,-98.602218(est)
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Administrative Information
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Investigator In Charge (IIC):
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Link, Samantha
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Additional Participating Persons:
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William J Fitzgerald; Federal Aviation Administration; Lubbock, TX
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Original Publish Date:
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October 20, 2021 Investigation Class:
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3
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Note:
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The NTSB did not travel to the scene of this accident.
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Investigation Docket:
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https://data.ntsb.gov/Docket?ProjectID=98599
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