Saturday, December 07, 2019

Powerplant System/Component Malfunction/Failure: Safari 400, N326RW; accident occurred July 02, 2018 in Aguilares, Webb County, Texas

Tail Boom and Tail Rotor 
Federal Aviation Administration

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:

Investigation Docket - National Transportation Safety Board:

Main Rotors 
Federal Aviation Administration

Location: Aguilares, TX
Accident Number: CEN18LA247
Date & Time: 07/02/2018, 1130 CDT
Registration: N326RW
Aircraft:SAFARI 400
Aircraft Damage: Substantial
Defining Event: Powerplant sys/comp malf/fail
Injuries: 1 Serious
Flight Conducted Under: Part 91: General Aviation - Personal

On July 2, 2018, about 1130 central daylight time, an amateur-built Safari Helicopters 400 helicopter, N326RW, impacted the ground following a loss of control near Aguilares, Texas. The private pilot sustained serious injuries, and the helicopter sustained substantial damage. The helicopter was owned by Panda Ventures, LLC, and was operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no Federal Aviation Administration (FAA) flight plan had been filed for the flight. The personal flight departed Slator Ranch, near Aguilares, Texas, about 1000.

According to a statement given to the responding FAA inspector, the pilot was working on the Phase I flight test requirements following the experimental certification of his helicopter. The helicopter had about 25 hours total time since it was built from a commercial kit. The helicopter was in straight and level flight, between 20 and 30 ft above ground level when it started to shudder. The pilot started to look for a place to land; he then heard a "pop" and the helicopter immediately lost tail rotor authority. The helicopter started to rotate counterclockwise, and the pilot attempted to stop the rotation without success. The helicopter impacted the ground and rolled onto its left side. The fuselage was crushed and buckled, and both main rotor blades were substantially damaged.

A teardown and examination of the transmission revealed that the tail rotor pinion had failed. The tail rotor pinion was located inside of the transmission. The exterior of the transmission exhibited impact damage at the mast but was otherwise unremarkable. There was no damage to the tail rotor blades or the tail rotor driveshaft. There were no other mechanical anomalies noted with the helicopter or its systems that would have precluded normal operations.

The tail rotor pinion was shipped to the National Transportation Safety Board's Materials Laboratory for further examination. Examination revealed that the tail rotor pinion shaft fractured between the portion carrying a beveled gear and that containing a helical gear. Both halves of the pinion shaft fracture surface exhibited mechanical damage by recontact resulting in rubbing of the fracture surfaces. No evidence of a preexisting crack was observed. The overall fracture macro-morphology was consistent with bending overstress. Microhardness measurement values were consistent with the specifications for the pinion shaft. Details of this examination are contained in a specialist report in the public docket for this accident.

According to a representative with Safari Helicopters, prior to the accident, Safari Helicopters found that a batch of pinions and gears were not hardened properly. The pinion in the accident helicopter was not part of the batch with the hardening issue.

Federal Aviation Administration

Pilot Information

Certificate: Private
Age:57, Male 
Airplane Rating(s): Multi-engine Land; Single-engine Land; Single-engine Sea
Seat Occupied: Left
Other Aircraft Rating(s): Helicopter
Restraint Used:
Instrument Rating(s): None
Second Pilot Present:No 
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 3 With Waivers/Limitations
Last FAA Medical Exam:04/25/2017 
Occupational Pilot: No
Last Flight Review or Equivalent: 12/05/2017
Flight Time: 13425 hours (Total, all aircraft), 27 hours (Total, this make and model), 35 hours (Last 90 days, all aircraft), 10 hours (Last 30 days, all aircraft)

Lower Fuselage and Skids 
Federal Aviation Administration

Aircraft and Owner/Operator Information

Aircraft Make: SAFARI
Registration: N326RW
Model/Series: 400
Aircraft Category: Helicopter
Year of Manufacture: 2018
Amateur Built: Yes
Airworthiness Certificate: Experimental
Serial Number: 6686
Landing Gear Type: High Skid; Skid
Seats: 2
Date/Type of Last Inspection: 05/15/2018, Condition
Certified Max Gross Wt.: 1650 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time: 24.33 Hours at time of accident
Engine Manufacturer: Aero Sport Power Ltd.
ELT: Not installed
Engine Model/Series: O-360-C2A
Registered Owner: On file
Rated Power: 185 hp
Operator: On file
Operating Certificate(s) Held:None  

Landing Skids and Engine 
Federal Aviation Administration

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: KLRD, 508 ft msl
Distance from Accident Site: 23 Nautical Miles
Observation Time: 1656 UTC
Direction from Accident Site: 320°
Lowest Cloud Condition: Clear
Visibility:  10 Miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 11 knots / 16 knots
Turbulence Type Forecast/Actual: None / None
Wind Direction:140° 
Turbulence Severity Forecast/Actual: N/A / N/A
Altimeter Setting: 29.97 inches Hg
Temperature/Dew Point: 34°C / 22°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Slator Ranch, TX
Type of Flight Plan Filed: None
Destination: Slator Ranch, TX
Type of Clearance: None
Departure Time: 1000
Type of Airspace: Class G


Federal Aviation Administration

Wreckage and Impact Information

Crew Injuries: 1 Serious
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 Serious
Latitude, Longitude: 27.150000, -99.110000 (est)

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