Saturday, November 27, 2021

Low Altitude Operation/Event: Robinson R44, N775AK; accident occurred August 04, 2021 in Waukon, Allamakee County, Iowa

Aviation Accident Final Report - National Transportation Safety Board

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

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Ankeny, Iowa

Investigation Docket - National Transportation Safety Board:

Location: Waukon, Iowa 
Accident Number: CEN21LA350
Date and Time: August 4, 2021, 08:15 Local
Registration: N775AK
Aircraft Damage: Substantial
Defining Event: Low altitude operation/event 
Injuries: 1 Minor
Flight Conducted Under: Part 137: Agricultural


The pilot was conducting an agricultural application pass when the helicopter struck a powerline crossing the cornfield being sprayed. He did not see the line until exiting the helicopter after the accident. Earlier in the morning he had surveyed the area for obstacles but did not observe any lines crossing the field. The pilot commented that his initial survey pass was completed toward the east with the sun “low in the sky and in [his] eyes.” He noted that there were no issues with the helicopter before contacting with the power line. The helicopter sustained substantial damage to the main rotor system, the fuselage, and the empennage.

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 from a powerline during an agricultural application pass.


Environmental issues Wire - Awareness of condition
Aircraft Altitude - Not attained/maintained
Personnel issues Monitoring environment - Pilot

Factual Information

History of Flight

Maneuvering-low-alt flying Low altitude operation/event (Defining event)

Pilot Information

Certificate: Commercial 
Age: 66, Male
Airplane Rating(s): Single-engine land; Single-engine sea
Seat Occupied: Right
Other Aircraft Rating(s): Helicopter 
Restraint Used: 3-point
Instrument Rating(s): Airplane 
Second Pilot Present: No
Instructor Rating(s): None 
Toxicology Performed:
Medical Certification: Class 2 With waivers/limitations 
Last FAA Medical Exam: September 24, 2020
Occupational Pilot: Yes 
Last Flight Review or Equivalent: March 15, 2021
Flight Time: 27652 hours (Total, all aircraft), 3015 hours (Total, this make and model)

Aircraft and Owner/Operator Information

Registration: N775AK
Model/Series: R44 
Aircraft Category: Helicopter
Year of Manufacture: 2008
Amateur Built:
Airworthiness Certificate: Restricted (Special) 
Serial Number: 1875
Landing Gear Type: Skid 
Seats: 4
Date/Type of Last Inspection: March 10, 2021 Annual 
Certified Max Gross Wt.: 2400 lbs
Time Since Last Inspection: 187.9 Hrs
Engines: 1 Reciprocating
Airframe Total Time: 1973.5 Hrs at time of accident
Engine Manufacturer: Lycoming
ELT: Not installed 
Engine Model/Series: O-540-F1B5
Registered Owner:
Rated Power: 260 Horsepower
Operating Certificate(s) Held: Agricultural aircraft (137)

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual (VMC)
Condition of Light: Day
Observation Facility, Elevation: DEH,1158 ft msl 
Distance from Accident Site: 16 Nautical Miles
Observation Time: 07:55 Local 
Direction from Accident Site: 273°
Lowest Cloud Condition: Clear
Visibility: 7 miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 0 knots / 0 knots 
Turbulence Type Forecast/Actual:  /
Wind Direction: 
Turbulence Severity Forecast/Actual:  /
Altimeter Setting: 30.14 inches Hg 
Temperature/Dew Point: 16°C / 16°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point:
Type of Flight Plan Filed: None
Destination: Waukon, IA
Type of Clearance: None
Departure Time: 
Type of Airspace: Class G

Wreckage and Impact Information

Crew Injuries: 1 Minor
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A 
Aircraft Explosion: None
Total Injuries: 1 Minor
Latitude, Longitude: 43.261185,-91.375664

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