Monday, September 06, 2021

Hard Landing: Bell 407, N489DM; accident occurred September 15, 2020 at Fort Worth Alliance Airport (KAFW), Texas

Aviation Accident Final Report - National Transportation Safety Board
Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; North Texas

Investigation Docket - National Transportation Safety Board:

Chaparral Air Group

Location: Fort Worth, Texas 
Accident Number: CEN20CA395
Date & Time: September 15, 2020, 16:53 Local 
Registration: N489DM
Aircraft: Bell 407
Aircraft Damage: Substantial
Defining Event: Hard landing
Injuries: 2 None
Flight Conducted Under: Part 91: General aviation - Instructional]


During a routine training flight, the helicopter was in the traffic pattern practicing power recovery autorotations, with the pilot under training at the flight controls. During the 5th practice auto-rotation, the flight instructor reduced the throttle, and the helicopter began a normal descent. During the deceleration flare, about 75 ft above ground level, the flight instructor heard the low rotor RPM audio tone. Using a positive transfer of control, the flight instructor quickly took the flight controls. He increased the throttle to what he believed to be the “FLY” position. The helicopter settled onto a taxiway. The main rotor blades severed the vertical fins on the horizontal stabilizer, and the tail rotor driveshaft was severed. The operator reported that the pilot did not rapidly roll the throttle to the “FLY” position during the deceleration/flare, and the helicopter contacted the ground at less than 100% rotor RPM. The operator stated that there were no mechanical anomalies with the helicopter that would have precluded normal

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The flight instructor’s delay in rolling the throttle to the fly position during a practice autorotation maneuver that resulted in a hard landing.


Personnel issues (general) - Instructor/check pilot
Aircraft Prop/rotor parameters - Related operating info
Aircraft Descent rate - Not attained/maintained

Factual Information

History of Flight

Landing-flare/touchdown Hard landing (Defining event)
Flight instructor Information
Certificate: Airline transport; Commercial; Flight instructor 
Age: 57, Male
Airplane Rating(s): Single-engine land; Multi-engine sea
Seat Occupied: Left
Other Aircraft Rating(s): Helicopter 
Restraint Used: 4-point
Instrument Rating(s): Helicopter 
Second Pilot Present: Yes
Instructor Rating(s): Helicopter; Instrument airplane 
Toxicology Performed: No
Medical Certification: Class 1 With waivers/limitations
Last FAA Medical Exam: August 31, 2020
Occupational Pilot: Yes 
Last Flight Review or Equivalent: July 28, 2020
Flight Time: 10300 hours (Total, all aircraft), 912 hours (Total, this make and model), 9290 hours (Pilot In Command, all aircraft), 145 hours (Last 90 days, all aircraft), 85 hours (Last 30 days, all aircraft), 1 hours (Last 24 hours, all aircraft)

Pilot Information

Certificate: Commercial 
Age: 41,Male
Airplane Rating(s): Single-engine sea
Seat Occupied: Right
Other Aircraft Rating(s): Helicopter
Restraint Used: 4-point
Instrument Rating(s): Airplane; Helicopter
Second Pilot Present: Yes
Instructor Rating(s): None 
Toxicology Performed:
Medical Certification: Class 2 Without waivers/limitations
Last FAA Medical Exam: June 29, 2020
Occupational Pilot: Yes
Last Flight Review or Equivalent: May 14, 2020
Flight Time: 1017 hours (Total, all aircraft), 135 hours (Total, this make and model), 878 hours (Pilot In Command, all aircraft), 129 hours (Last 90 days, all aircraft), 37 hours (Last 30 days, all aircraft), 1 hours (Last 24 hours, all aircraft)

Aircraft and Owner/Operator Information

Aircraft Make: Bell Registration: N489DM
Model/Series: 407 No Series 
Aircraft Category: Helicopter
Year of Manufacture: 2004 
Amateur Built:
Airworthiness Certificate: Normal 
Serial Number: 53619
Landing Gear Type: Ski; Skid
Seats: 6
Date/Type of Last Inspection: September 1, 2020 Annual
Certified Max Gross Wt.: 5250 lbs
Time Since Last Inspection: 36 Hrs 
Engines: 1 Turbo shaft
Airframe Total Time: 4775 Hrs at time of accident
Engine Manufacturer: Rolls-Royc
ELT: Installed, not activated 
Engine Model/Series: 250-C47B
Registered Owner: 
Rated Power: 650 Horsepower
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual (VMC)
Condition of Light: Day
Observation Facility, Elevation: AFW 
Distance from Accident Site: 1 Nautical Miles
Observation Time: 16:45 Local 
Direction from Accident Site: 80°
Lowest Cloud Condition: Clear
Visibility:  10 miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 10 knots / 
Turbulence Type Forecast/Actual: None / None
Wind Direction: 340° 
Turbulence Severity Forecast/Actual: N/A / N/A
Altimeter Setting: 29.94 inches Hg
Temperature/Dew Point: 22°C / 16°C
Precipitation and Obscuration:
Departure Point: Fort Worth, TX (AFW)
Type of Flight Plan Filed: Company VFR
Destination: Fort Worth, TX 
Type of Clearance: None
Departure Time: 15:55 Local 
Type of Airspace: Class E

Airport Information

Airport: Fort Worth AFW 
Runway Surface Type:
Airport Elevation: 723 ft msl 
Runway Surface Condition: Dry
Runway Used: 
IFR Approach: None
Runway Length/Width:
VFR Approach/Landing: Traffic pattern

Wreckage and Impact Information

Crew Injuries: 2 None
Aircraft Damage: Substantial
Passenger Injuries:
Aircraft Fire: None
Ground Injuries: 
Aircraft Explosion: None
Total Injuries: 2 None 
Latitude, Longitude: 32.5942,-97.1917

1 comment:

  1. The infamous “coffin corner” that every helicopter shares, some higher than others. While flying OH-58F Kiowas ( military version of the 407 ) in the Army, one of the things you learn is how long it takes for that Rolls Royce turbine to spool up after rotor speed decays. To low and you’re going to kiss mother earth. As an instructor at Ft Hood, my eyes were fixated on rotor speed and turbine ( NR ..NP ) below 250 feet, and it was drilled into candidates minds as well.