The National Transportation Safety Board did not travel to the scene of this accident.
Additional Participating Entity:
Aviation Accident Final Report - National Transportation Safety Board
Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Little Rock, Arkansas
Federal Aviation Administration / Flight Standards District Office; North Texas
Investigation Docket - National Transportation Safety Board:
Arkansas Children's Hospital
Location: Texarkana, Arkansas
Accident Number: CEN22LA147
Date and Time: March 12, 2022, 18:45 Local
Registration: N761AF
Aircraft: SIKORSKY AIRCRAFT CORP S-76D
Aircraft Damage: Substantial
Defining Event: Collision with terr/obj (non-CFIT)
Injuries: 3 None
Flight Conducted Under: Part 135: Air taxi & commuter - Non-scheduled - Air Medical (Discretionary)
Analysis
The pilot reported that he was on approach to a hospital rooftop helipad that he had never landed at before. About 30 ft above ground level, he felt a “thump” in the pedals; the helicopter vibrated, pitched forward, rolled left, then yawed right. The pilot landed the helicopter on the helipad. After the accident the pilot discovered that the tail rotor had contacted the building.
The helicopter sustained substantial damage to the tail rotor, tail rotor drivetrain, and tail pylon. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation.
Probable Cause and Findings
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The pilot’s failure to maintain adequate clearance during landing on a rooftop helipad.
Findings
Personnel issues Total experience - Pilot
Factual Information
History of Flight
Maneuvering-hover Collision with terr/obj (non-CFIT) (Defining event)
Pilot Information
Certificate: Commercial
Age: 54, Male
Airplane Rating(s): None
Seat Occupied: Right
Other Aircraft Rating(s):
Helicopter Restraint Used: 5-point
Instrument Rating(s): Helicopter
Second Pilot Present: No
Instructor Rating(s): Helicopter; Instrument helicopter
Toxicology Performed:
Medical Certification: Class 1 Without waivers/limitations
Last FAA Medical Exam: November 16, 2021
Occupational Pilot: Yes
Last Flight Review or Equivalent: December 30, 2021
Flight Time: (Estimated) 3211 hours (Total, all aircraft), 173 hours (Total, this make and model), 1879 hours (Pilot In Command, all aircraft), 128 hours (Last 90 days, all aircraft), 32 hours (Last 30 days, all aircraft), 2 hours (Last 24 hours, all aircraft)
Aircraft and Owner/Operator Information
Aircraft Make: SIKORSKY AIRCRAFT CORP
Registration: N761AF
Model/Series: S-76D
Aircraft Category: Helicopter
Year of Manufacture: 2013
Amateur Built:
Airworthiness Certificate: Transport
Serial Number: 761039
Landing Gear Type: Retractable - Tricycle; Skid
Seats: 6
Date/Type of Last Inspection: February 20, 2022 Continuous airworthiness
Certified Max Gross Wt.: 11875 lbs
Time Since Last Inspection:
Engines: 2 Turbo shaft
Airframe Total Time: 4747.7 Hrs at time of accident
Engine Manufacturer: Pratt and Whitney Canada
ELT: C126 installed, not activated
Engine Model/Series: PW210S
Registered Owner:
Rated Power: 1123 Lbs thrust
Operator:
Operating Certificate(s) Held: On-demand air taxi (135)
Meteorological Information and Flight Plan
Conditions at Accident Site: Visual (VMC)
Condition of Light: Day
Observation Facility, Elevation: KTXK,389 ft msl
Distance from Accident Site: 3.2 Nautical Miles
Observation Time: 19:15 Local
Direction from Accident Site: 242°
Lowest Cloud Condition: Clear / 0 ft AGL
Visibility 10 miles
Lowest Ceiling: None / 0 ft AGL
Visibility (RVR):
Wind Speed/Gusts: /
Turbulence Type Forecast/Actual: None / None
Wind Direction:
Turbulence Severity Forecast/Actual: N/A / N/A
Altimeter Setting: 30.34 inches Hg
Temperature/Dew Point: 9°C / -10°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Little Rock, AR (AR62)
Type of Flight Plan Filed: Company VFR
Destination: Texarkana, AR
Type of Clearance: VFR;Traffic advisory; VFR flight following
Departure Time: 17:34 Local
Type of Airspace: Class D
Airport Information
Airport: Heliport Texarkana Wadley Regional Medical Center 64XS
Runway Surface Type:
Airport Elevation: 347 ft msl
Runway Surface Condition: Dry
Runway Used:
IFR Approach: None
Runway Length/Width:
VFR Approach/Landing: Forced landing; Full stop; Straight-in
Wreckage and Impact Information
Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: 2 None
Aircraft Fire: None
Ground Injuries:
Aircraft Explosion: None
Total Injuries: 3 None
Latitude, Longitude: 33.428844,-94.047933(est)
Location: Texarkana, Arkansas
Accident Number: CEN22LA147
Date and Time: March 12, 2022, 18:45 Local
Registration: N761AF
Aircraft: SIKORSKY AIRCRAFT CORP S-76D
Injuries: 1 None
Flight Conducted Under: Part 135: Air taxi and commuter - Non-scheduled - Air Medical (Discretionary)
Aircraft and Owner/Operator Information
Aircraft Make: SIKORSKY AIRCRAFT CORP
Registration: N761AF
Model/Series: S-76D Aircraft Category: Helicopter
Amateur Built:
Operator:
Operating Certificate(s) Held: On-demand air taxi (135)
Operator Designator Code:
Meteorological Information and Flight Plan
Conditions at Accident Site:
Condition of Light:
Observation Facility, Elevation:
Observation Time:
Distance from Accident Site:
Temperature/Dew Point:
Lowest Cloud Condition:
Wind Speed/Gusts, Direction: / ,
Lowest Ceiling:
Visibility:
Altimeter Setting:
Type of Flight Plan Filed:
Departure Point:
Destination:
Wreckage and Impact Information
Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries:
Aircraft Explosion: None
Total Injuries: 1 None
Latitude, Longitude: 33.428844,-94.047933 (est)
The National Transportation Safety Board did not travel to the scene of this accident.
Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Little Rock, Arkansas
Investigation Docket - National Transportation Safety Board:
Arkansas Children's Hospital
Location: Morrilton, ArkansasAccident Number: CEN19LA146
Date and Time: May 15, 2019, 18:33 Local
Registration: N761AF
Aircraft: Sikorsky S76
Aircraft Damage: Substantial
Defining Event: Powerplant sys/comp malf/fail
Injuries: 6 None
Flight Conducted Under: Part 135: Air taxi and commuter - Non-scheduled - Air Medical (Unspecified)
Analysis
The pilot of the helicopter air ambulance flight reported that he experienced fumes in the cockpit while enroute, and shortly thereafter, received visual and aural warnings of smoke in the aft baggage compartment. The pilot initiated an emergency descent into an alternate airport, declared an emergency with air traffic control, and landed uneventfully.
Examination of the helicopter revealed that the No. 2 engine exhaust duct was disconnected and unseated, which resulted in engine exhaust entering the compartment containing the tail rotor drive shaft and substantial heat damage to the drive shaft and surrounding areas. Examination of the No. 1 engine exhaust duct revealed that its attach bolts were not tightened to the specified torque value. Additionally, examination of the operator’s other helicopter revealed that the bolts securing both of its two exhaust ducts were not tightened to the specified torque value. The maintenance history of these components was not determined, but given the available information, it is likely that they were improperly secured, which resulted in their loosening and subsequently allowed the exhaust duct to become unseated.
Probable Cause and Findings
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The improper securing of the exhaust duct bolts, which resulted in the duct becoming unseated and substantial heat damage to the tail rotor drive shaft.
Findings
Aircraft Fasteners - Incorrect service/maintenance
Aircraft (general) - Incorrect service/maintenance
Personnel issues (general) - Maintenance personnel
Factual Information
On May 15, 2019, about 1833 central daylight time, a Sikorsky S-76D helicopter, N761AF, sustained substantial damage while in cruise flight near Morrilton, Arkansas. The pilot, 2 crewmembers, and 3 passengers were not injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 135 on-demand air medical flight.
The pilot reported that, 43 minutes into the flight, he experienced fumes in the cockpit. He turned the environmental control system off and immediately descended. Within seconds, he received visual and aural warnings of smoke in the aft baggage compartment. He initiated an emergency descent and declared an emergency with air traffic control and subsequently landed without further incident.
A postaccident examination of the helicopter by a Federal Aviation Administration inspector revealed that the exhaust duct from the No. 2 engine was disconnected and not in its seated position. Exhaust from the No. 2 engine entered the compartment containing the tail rotor drive shaft and resulted in heat damage to drive shaft and surrounding areas. The exhaust ducts are attached using two bolts secured at 110 ft-lbs of pressure. Upon inspection of the No. 1 engine, as well as the operator’s second helicopter, all bolts were found partially disengaged and not tightened to the specified torque value.
History of Flight
Enroute-cruise Powerplant sys/comp malf/fail (Defining event)
Pilot Information
Certificate: Airline transport; Commercial
Age: 50,Male
Airplane Rating(s): Single-engine land; Multi-engine sea
Seat Occupied: Right
Other Aircraft Rating(s): Helicopter
Restraint Used: 5-point
Instrument Rating(s): Airplane; Helicopter
Second Pilot Present: No
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 1 Without waivers/limitations
Last FAA Medical Exam: April 29, 2019
Occupational Pilot: Yes
Last Flight Review or Equivalent: March 28, 2019
Flight Time: 6518 hours (Total, all aircraft), 431 hours (Total, this make and model), 5165 hours (Pilot In Command, all aircraft), 32 hours (Last 90 days, all aircraft), 13 hours (Last 30 days, all aircraft), 4 hours (Last 24 hours, all aircraft)
Other flight crew Information
Certificate: None
Age: Male
Airplane Rating(s): None
Seat Occupied: Rear
Other Aircraft Rating(s): None
Restraint Used: 4-point
Instrument Rating(s): None
Second Pilot Present: No
Instructor Rating(s): None
Toxicology Performed:
Medical Certification: None
Last FAA Medical Exam:
Occupational Pilot: No
Last Flight Review or Equivalent:
Flight Time:
Other flight crew Information
Certificate: None
Age: Male
Airplane Rating(s): None
Seat Occupied: Rear
Other Aircraft Rating(s): None
Restraint Used: 4-point
Instrument Rating(s): None
Second Pilot Present: No
Instructor Rating(s): None
Toxicology Performed:
Medical Certification: None
Last FAA Medical Exam:
Occupational Pilot: No
Last Flight Review or Equivalent:
Flight Time:
Passenger Information
Certificate:
Age:
Airplane Rating(s):
Seat Occupied: Center
Other Aircraft Rating(s):
Restraint Used: 4-point
Instrument Rating(s):
Second Pilot Present: No
Instructor Rating(s):
Toxicology Performed:
Medical Certification:
Last FAA Medical Exam:
Occupational Pilot:
Last Flight Review or Equivalent:
Flight Time:
Passenger Information
Certificate:
Age: Female
Airplane Rating(s):
Seat Occupied: Right
Other Aircraft Rating(s):
Restraint Used: 4-point
Instrument Rating(s):
Second Pilot Present: No
Instructor Rating(s):
Toxicology Performed:
Medical Certification:
Last FAA Medical Exam:
Occupational Pilot:
Last Flight Review or Equivalent:
Flight Time:
Passenger Information
Certificate:
Age: Male
Airplane Rating(s):
Seat Occupied: Right
Other Aircraft Rating(s):
Restraint Used: 4-point
Instrument Rating(s):
Second Pilot Present: No
Instructor Rating(s):
Toxicology Performed:
Medical Certification:
Last FAA Medical Exam:
Occupational Pilot:
Last Flight Review or Equivalent:
Flight Time:
Aircraft and Owner/Operator Information
Aircraft Make: Sikorsky
Registration: N761AF
Model/Series: S76
Aircraft Category: Helicopter
Year of Manufacture: 2013
Amateur Built:
Airworthiness Certificate: Transport
Serial Number: 761039
Landing Gear Type: Tricycle
Seats: 6
Date/Type of Last Inspection: March 13, 2019 Continuous airworthiness
Certified Max Gross Wt.: 11875 lbs
Time Since Last Inspection: 205 Hrs
Engines: 2 Turbo shaft
Airframe Total Time: 2488 Hrs as of last inspection
Engine Manufacturer: Pratt and Whitney
ELT: C126 installed, not activated
Engine Model/Series: PW210S
Registered Owner:
Rated Power: 1248 Horsepower
Operator:
Operating Certificate(s) Held: On-demand air taxi (135)
Meteorological Information and Flight Plan
Conditions at Accident Site: Visual (VMC)
Condition of Light: Day
Observation Facility, Elevation: KRUE, 403 ft msl
Distance from Accident Site: 25 Nautical Miles
Observation Time: 18:53 Local
Direction from Accident Site: 285°
Lowest Cloud Condition: Clear
Visibility 10 miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 4 knots /
Turbulence Type Forecast/Actual: /
Wind Direction: 300°
Turbulence Severity Forecast/Actual: /
Altimeter Setting: 29.9 inches Hg
Temperature/Dew Point: 29°C / 18°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Springdale, AR (14AR)
Type of Flight Plan Filed: Company VFR
Destination: Little Rock, AR (AR62)
Type of Clearance: VFR flight following
Departure Time: 17:50 Local
Type of Airspace: Class E
Airport Information
Airport: MORRILTON MUNI BDQ
Runway Surface Type: Asphalt
Airport Elevation: 321 ft msl
Runway Surface Condition: Dry
Runway Used: 09/27
IFR Approach: None
Runway Length/Width: 4000 ft / 75 ft
VFR Approach/Landing: None
Wreckage and Impact Information
Crew Injuries: 3 None
Aircraft Damage: Substantial
Passenger Injuries: 3 None
Aircraft Fire: None
Ground Injuries:
Aircraft Explosion: None
Total Injuries: 6 None
Latitude, Longitude: 35.1018,-92.7652 (est)
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