Sunday, March 07, 2021

Loss of Control on Ground: de Havilland Canada DHC-6-300 Twin Otter, N72GC; accident occurred March 06, 2020 at Boulder City Municipal Airport (KBVU), Clark County, Nevada

Aviation Accident Final Report - National Transportation Safety Board

Additional Participating Entity: 
Federal Aviation Administration / Flight Standards District Office; Las Vegas, Nevada

Investigation Docket - National Transportation Safety Board:

Date & Time: March 6, 2020, 11:15 Local
Registration: N72GC
Aircraft: De Havilland DHC6 
Aircraft Damage: Substantial
Defining Event: Loss of control on ground 
Injuries: 2 None
Flight Conducted Under: Part 91: General aviation - Instructional


An operator's pilot was conducting training for a newly hired pilot for a first officer position in the twin-engine airplane. After accomplishing air work, the pilots returned to the airport to practice landings and takeoffs. According to both pilots, the first approach was normal, and the airplane touched down slightly right of the runway centerline. The trainee pilot stated that, after touchdown, the airplane began drifting further right and that he was unable to correct the deviation. The trainer pilot reported that, when directional control became unstable, he told the trainee, "I have the controls." The trainer pilot saw that the trainee pilot released his hands from the engine power levers and the yoke, but the airplane continued to deviate to the right, contrary to his control inputs and his addition of asymmetric power to the engines. The trainer pilot realized that, based on his inputs, the airplane should have returned to the centerline but that it did not and that it was behaving as if the trainee pilot was applying some braking. At that point, the trainer pilot again told the trainee pilot to release the controls, and he used the brakes, which he reported applied and released normally. Subsequently, the airplane exited the right side of the runway and impacted a ditch. The airplane sustained substantial damage to the right wing. The trainer pilot and the operator reported that there were no mechanical failures or malfunctions with the airplane that would have precluded normal operation. The trainer pilot reported that he believed the trainee pilot's feet were either on the brakes or interfered with his brake and/or rudder application attempts. The trainee pilot reported that he could not recall the position of his feet after he relinquished airplane control to the trainer pilot.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The trainee pilot's loss of directional control during landing and his subsequent unintentional control interference with the brakes and/or rudder during the trainer pilot's attempted remedial action, which resulted in a runway excursion and collision with a ditch.


Aircraft Directional control - Not attained/maintained
Personnel issues Aircraft control - Student/instructed pilot
Personnel issues Use of equip/system - Student/instructed pilot
Aircraft Brake - Unintentional use/operation
Aircraft Rudder control system - Unintentional use/operation
Environmental issues Sloped/uneven terrain - Effect on operation

Factual Information

History of Flight

Landing-landing roll Loss of control on ground (Defining event)
Landing-landing roll Attempted remediation/recovery
Landing-landing roll Runway excursion
Landing-landing roll Collision with terr/obj (non-CFIT)

Flight instructor Information

Certificate: Airline transport
Age: 55, Male
Airplane Rating(s): Multi-engine land
Seat Occupied: Left
Other Aircraft Rating(s): None
Restraint Used: 4-point
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 1 With waivers/limitations
Last FAA Medical Exam: February 25, 2020
Occupational Pilot: Yes 
Last Flight Review or Equivalent: October 22, 2019
Flight Time: 23500 hours (Total, all aircraft), 20000 hours (Total, this make and model), 18500 hours (Pilot In Command, all aircraft), 75 hours (Last 90 days, all aircraft), 28 hours (Last 30 days, all aircraft), 3 hours (Last 24 hours, all aircraft)

Pilot Information

Certificate: Commercial; Private 
Age: 52, Male
Airplane Rating(s): Single-engine land; Multi-engine land
Seat Occupied: Right
Other Aircraft Rating(s): None 
Restraint Used: 4-point
Instrument Rating(s): Airplane
Second Pilot Present: Yes
Instructor Rating(s): None 
Toxicology Performed: No
Medical Certification: Class 1 With waivers/limitations
Last FAA Medical Exam: January 17, 2020
Occupational Pilot: Yes
Last Flight Review or Equivalent: September 26, 2018
Flight Time: 583 hours (Total, all aircraft), 4 hours (Total, this make and model), 539 hours (Pilot In Command, all aircraft), 8 hours (Last 90 days, all aircraft), 6 hours (Last 30 days, all aircraft), 1 hours (Last 24 hours, all aircraft)

Aircraft and Owner/Operator Information

Aircraft Make: De Havilland 
Registration: N72GC
Model/Series: DHC6 300 
Aircraft Category: Airplane
Year of Manufacture: 1969 
Amateur Built: No
Airworthiness Certificate: Normal
Serial Number: 264
Landing Gear Type: Tricycle 
Seats: 21
Date/Type of Last Inspection: September 25, 2019 Continuous airworthiness
Certified Max Gross Wt.: 12500 lbs
Time Since Last Inspection: 
Engines: 2 Turbo prop
Airframe Total Time: 50964 Hrs as of last inspection
Engine Manufacturer:
ELT: Installed, not activated 
Engine Model/Series:
Registered Owner: 
Rated Power:
Operating Certificate(s) Held: Commercial air tour (136)

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual (VMC) 
Condition of Light: Day
Observation Facility, Elevation: BVU,2200 ft msl
Distance from Accident Site: 0 Nautical Miles
Observation Time: 11:15 Local
Direction from Accident Site:
Lowest Cloud Condition: Clear 
Visibility 10 miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 5 knots /
Turbulence Type Forecast/Actual:  /
Wind Direction: 
Turbulence Severity Forecast/Actual:  /
Altimeter Setting: 30.07 inches Hg
Temperature/Dew Point: 21°C / -1°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Boulder City, NV (BVU) 
Type of Flight Plan Filed: Company VFR
Destination: Boulder City, NV (BVU) 
Type of Clearance: None
Departure Time: 10:05 Local
Type of Airspace: Class E

Airport Information

Airport: Boulder City BVU
Runway Surface Type: Asphalt
Airport Elevation: 2200 ft msl 
Runway Surface Condition: Dry
Runway Used: 27
IFR Approach: None
Runway Length/Width: 4803 ft / 75 ft 
VFR Approach/Landing: Traffic pattern

Wreckage and Impact Information

Crew Injuries: 2 None 
Aircraft Damage: Substantial
Passenger Injuries:
Aircraft Fire: None
Ground Injuries: N/A 
Aircraft Explosion: None
Total Injuries: 2 None 
Latitude, Longitude: 35.947223,-114.864723(est)

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