Saturday, February 02, 2019

Flight Control System Malfunction/Failure: Robinson R44 Raven II, N484AB; accident occurred January 08, 2019 near Garner Field Airport (KUVA), Uvalde, Texas

The National Transportation Safety Board did not travel to the scene of this accident.

Additional Participating Entity: 

Federal Aviation Administration / Flight Standards District Office; San Antonio, Texas

Aviation Accident Factual Report - National Transportation Safety Board: https://app.ntsb.gov/pdf


Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms 

https://registry.faa.gov/N484AB

Location: Uvalde, TX
Accident Number: CEN19LA065
Date & Time: 01/08/2019, 1000 CST
Registration: N484AB
Aircraft: Robinson R44
Aircraft Damage: Substantial
Defining Event: Flight control sys malf/fail
Injuries: 1 Minor, 1 None
Flight Conducted Under: Part 91: General Aviation - Instructional 

On January 8, 2019, about 1000 central standard time, a Robinson R44 II helicopter, N484AB, experienced a hard landing during an autorotation shortly after takeoff from Garner Field Airport, Uvalde, Texas. The flight instructor sustained minor injuries, the student pilot was not injured, and the helicopter sustained substantial damage. The helicopter was registered to and operated by a private individual as a Title 14 Code of Federal Regulations Part 91 instructional flight. Visual meteorological conditions prevailed at the time of the accident, and a flight plan was not filed. The local flight was originating at the time of the accident.

According to the flight instructor, all pre-takeoff checks were normal with no anomalies noted. Once the helicopter was through effective translational lift and about 40 knots airspeed, the collective was raised to increase the available power to takeoff power setting. Shortly thereafter, a loud pop/bang was heard followed by an uncommanded right yaw and severe vibrations. Due to the low altitude and airspeed, the flight instructor immediately initiated an autorotation. Upon touchdown, the helicopter tilted forward with the main rotor blades about 6 inches from contacting the ground. The flight instructor applied aft cyclic to correct, and the main rotor blades contacted the tailboom.

Postaccident examination of the helicopter revealed the tailboom was partially separated, and the tail rotor driveshaft system was damaged. During the examination, the clutch assembly lubricant was drained and an unusual amount of metallic debris was noted in the strainer. The clutch assembly was removed and sent to Robinson Helicopter Company for further examination.

Examination and disassembly of the clutch assembly revealed galling of the sprags and the corresponding sprag contact surfaces on the shaft and hub.

According to the Robinson R44 maintenance manual, the clutch assemblies are to be inspected for metallic flakes every 500 hours. The most recent inspection on the clutch assembly was completed on April 18, 2018, about 245 hours prior to the accident.

Flight Instructor Information

Certificate: Flight Instructor; Commercial
Age: 30, Male
Airplane Rating(s):None 
Seat Occupied:Left 
Other Aircraft Rating(s): Helicopter
Restraint Used: 3-point
Instrument Rating(s): Helicopter
Second Pilot Present: Yes
Instructor Rating(s): Helicopter; Instrument Helicopter
Toxicology Performed: No
Medical Certification: Class 1 With Waivers/Limitations
Last FAA Medical Exam: 09/18/2018
Occupational Pilot: Yes
Last Flight Review or Equivalent: 08/15/2018
Flight Time:  2650 hours (Total, all aircraft), 1200 hours (Total, this make and model), 2600 hours (Pilot In Command, all aircraft), 250 hours (Last 90 days, all aircraft), 150 hours (Last 30 days, all aircraft), 5 hours (Last 24 hours, all aircraft)

Student Pilot Information

Certificate: Private
Age: 39, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Right
Other Aircraft Rating(s): None
Restraint Used: 3-point
Instrument Rating(s): None
Second Pilot Present:Yes 
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 2 Without Waivers/Limitations
Last FAA Medical Exam: 04/04/2018
Occupational Pilot: No
Last Flight Review or Equivalent:
Flight Time:   400 hours (Total, all aircraft), 20 hours (Total, this make and model), 320 hours (Pilot In Command, all aircraft), 25 hours (Last 90 days, all aircraft), 10 hours (Last 30 days, all aircraft), 1 hours (Last 24 hours, all aircraft)

Aircraft and Owner/Operator Information

Aircraft Make: Robinson
Registration: N484AB
Model/Series: R44 II
Aircraft Category: Helicopter
Year of Manufacture: 2006
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 11390
Landing Gear Type: Skid;
Seats: 4
Date/Type of Last Inspection: 11/07/2018, Annual
Certified Max Gross Wt.: 2500 lbs
Time Since Last Inspection: 245 Hours
Engines: 1 Reciprocating
Airframe Total Time: 1680.9 Hours at time of accident
Engine Manufacturer: Lycoming
ELT: Not installed
Engine Model/Series: IO-540-AE1A5
Registered Owner: Bodie Nunn
Rated Power: 205 hp
Operator: On file
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation:
Distance from Accident Site:
Observation Time: 0930 CST
Direction from Accident Site: 
Lowest Cloud Condition: Clear
Visibility:  10 Miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: Calm /
Turbulence Type Forecast/Actual: None / None
Wind Direction:  
Turbulence Severity Forecast/Actual: N/A / N/A
Altimeter Setting: 29.95 inches Hg
Temperature/Dew Point: 25°C / 15°C
Precipitation and Obscuration: No Precipitation
Departure Point: Uvalde, TX (UVA)
Type of Flight Plan Filed: None
Destination: Uvalde, TX (UVA)
Type of Clearance: None
Departure Time: 1000 CST
Type of Airspace: Class G

Airport Information

Airport: Garner Field (UVA)
Runway Surface Type: N/A
Airport Elevation: 941 ft
Runway Surface Condition: Dry
Runway Used: N/A
IFR Approach: None
Runway Length/Width:
VFR Approach/Landing: Forced Landing 

Wreckage and Impact Information

Crew Injuries: 1 Minor, 1 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 Minor, 1 None

Latitude, Longitude: 29.210278, -99.743056 (est)

Location: Uvalde, TX
Accident Number: CEN19LA065
Date & Time: 01/08/2019, 1000 CST
Registration: N484AB
Aircraft: Robinson R44
Injuries: 1 Minor, 1 None
Flight Conducted Under: Part 91: General Aviation - Instructional 

On January 8, 2019, about 1000 central standard time, a Robinson R44 II helicopter, experienced a hard landing during an autorotation following a loss of tail rotor effectiveness while maneuvering shortly after takeoff from Garner Field Airport, Uvalde, Texas. The flight instructor sustained minor injuries, the student pilot was not injured, and the helicopter sustained substantial damage. The helicopter was registered to and operated by a private individual as a Title 14 Code of Federal Regulations Part 91 instructional flight. Visual meteorological conditions prevailed at the time of the accident, and a flight plan was not filed. The local flight was originating at the time of the accident.

According to the flight instructor, all pre-takeoff checks were normal with no anomalies noted. Once the helicopter was through effective translational lift and about 40 knots airspeed, the collective was raised to increase the available power to takeoff power setting. Shortly thereafter, a loud pop/bang was heard with an uncommanded right yaw and severe vibrations. Due to the low altitude and airspeed, the flight instructor immediately initiated an autorotation. Upon touchdown, the helicopter titled forward with the main rotor blades about 6 inches from contacting the ground. The flight instructor applied aft cyclic to correct, and the main rotor blades contacted the tailboom.

Postaccident examination of the helicopter revealed the tailboom was partially separated, and the tail rotor driveshaft system was damaged. The helicopter was recovered to a helicopter maintenance facility. During the examination, the clutch lubricant was drained and an unusual amount of metallic debris was noted in the strainer. The clutch was removed and sent to Robinson Helicopter Company for further examination.

Aircraft and Owner/Operator Information

Aircraft Make: Robinson
Registration: N484AB
Model/Series: R44 II
Aircraft Category: Helicopter
Amateur Built: No
Operator: On file
Operating Certificate(s) Held: None 

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation:
Observation Time: 0930 CST
Distance from Accident Site:
Temperature/Dew Point: 25°C / 15°C
Lowest Cloud Condition: Clear
Wind Speed/Gusts, Direction: Calm / ,
Lowest Ceiling: None
Visibility:  10 Miles
Altimeter Setting: 29.95 inches Hg
Type of Flight Plan Filed: None
Departure Point: Uvalde, TX (UVA)
Destination: Uvalde, TX (UVA) 

Wreckage and Impact Information

Crew Injuries: 1 Minor, 1 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 Minor, 1 None
Latitude, Longitude: 29.210278, -99.743056 (est)

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