A challenging time for aerial applicators as they share the air with other aircraft | TheFencePost.com

A challenging time for aerial applicators as they share the air with other aircraft

Aerial applicators will soon be seen flying over farm land. With increased technology comes an increased risk of drone and aircraft collision at low altitude.
Photo courtesy Jessica Freeman

Spring is marked in farm country by field work, the movement of equipment between fields, and aerial spraying, all of which are jobs that require an eye for safety. Drones, both used by hobbyists and used commercially, often for field imaging, are a tool more producers are utilizing that also pose a risk for ag pilots.

According to Jessica Freeman, executive director of the Colorado Agricultural Aviation Association (CoAAA), 14 industries fly legally below 400 feet of altitude and neither ag pilots, nor drone pilots want the two to collide.

In the eyes of the Federal Aviation Administration, it is the responsibility of the UAS, or drone, operator to see and avoid manned aircraft, leaving the UAS operator “an unknown liability if there is an accident.” In 2014, there were multiple close calls reported, most of which the FAA said resulted from a lack of knowledge rather than malicious intent on the part of the UAS operator. There were close calls between UAS and agricultural aircraft, a news media helicopter in Seattle, and the New York Police Department helicopters in two separate incidences.

Sam Rogge, past president of the CoAAA, experienced a bird strike in 2001 when a duck hit and came through the front wind screen of his aircraft at about 50 feet above ground level. According to a CoAAA fact sheet, Rogge had just completed the last spray pass on a field, pulled over power lines, and began a turn to ferry to the next field. The Mallard hen, weighing approximately 3 pounds, struck Rogge in the chest at approximately 150 miles per hour, before continuing out the back glass. Rogge’s lost his vision temporarily but was able to land the aircraft before being taken to the hospital. Rogge flies with a helmet with a visor, saving his face and eyes, and he made a full recovery and returned to aerial application.

Like a bird strike, a drone collision is potentially deadly, made more so by the lithium ion battery in the drone, a significant fire hazard.

With an increasing use of wind energy in Colorado, the use of Meteorological Evaluation Towers (MET towers) is increasing. The towers, used to determine location suitability for the placement of wind towers, are 200 feet above ground level and, as such, do not have to be on aviation charts or marked in accordance with the FAA definition of obstructions. The towers are often in proximity to agricultural land, are slim and difficult for a pilot to see, and are stabilized with guy wires.

Multiple fatalities have occurred from collisions with MET towers in the United States, including the death of 25-year aerial application veteran Stephen Allen in California. His family was awarded $6.7 million in a wrongful death suit in 2014 when it was determined that Allen was not made aware of the MET tower by the landowner, property manager, or client that contracted the spray job.

Freeman said Colorado passed legislation requiring MET towers to be properly marked in order to be visible to a pilot. Colorado Sen. Jerry Sonnenberg, she said, was a staunch advocate for Colorado legislation requiring tower markings and the FAA adopted the state’s language.


In Colorado, there are approximately 42 active spray operations with an average of 80 to 85 pilots flying for those operations, typically flying in the 0 to 500 feet above ground level altitude. Though the pilot visually inspects each field for obstacles and hazards prior to lining up a spray pass, there are a number of challenges. According to the National Agricultural Aviation Association, aerial application is completed at 8-20 feet above ground level with trees and crops frequently blocking both the sound and view of the aircraft from others in the air space. Fixed wing aircraft climb rapidly out of the field and turn around over adjacent land to the field being sprayed.

Of the 85 pilots in Colorado, each is averaging 300 hours per year for a total average of 24,000 hours spent below 500 feet above ground level. These pilots comprise only one of the manned industries operating at low altitude.

The NAAA requires that drone operators remain below 400 feet above ground level and outside of five miles from any airport or airfield; keep the aircraft in sight at all times; and stay clear of temporary flight restrictions and media interest areas including fires, crime scenes and sporting events. With first responders, birds, aerial firefighters, aerial applicators, towers, and general aircraft hazards existing in low altitude, the responsibility to see and avoid hazards is the drone operators’.

Other examples of low altitude manned flight operations include coyote hunters, military helicopters, air tankers, livestock roundup helicopters, powerline and pipeline patrol operators, law enforcement helicopters, power line maintenance operators, game catch and survey operators, helicopters used for GIS mapping of noxious weed populations, power line erection companies, and seismic operators.

Freeman said UAS Colorado, a trade organization for drone operators in the state, has partnered with CoAAA on a safety project called Think Before You Launch. It included a visibility test between a drone and ag aircraft and a YouTube video from the Colorado Department of Agriculture.

“It comes from both sides,” she said. “It’s not just us complaining, it’s drone operators saying, ‘we need to be careful­ — we can all work we just can’t be in the same space at the same time.’”

Freeman said it may be unlikely for an aerial applicator and a drone to be in the same field, aerial applicators need room over adjacent fields to turn between passes.

“It’s not so much that we would be in the same field, it’s just that we need room to turn over another field,” she said. “What scares us is if Farmer A hires somebody to come in and spray, and Farmer B, with a neighboring field hires somebody to image. If we both cross that border at the same time, do we have a collision?”

Freeman said the unique situation requires education. Without flight planning or technical solutions for deconfliction, communication and cooperation is vital to avoid potentially fatal collisions. Aerial applicators cannot see drones in the air from a distance allowing them to avoid a crash. With this, and the FAA regulations placing the responsibility to avoid aircraft on the shoulders of the drone operator, the liability and danger are both extremely high.

“We realize we have to share the air and we realize it’s not the easiest thing in the world to communicate, but how do we make this better so everybody is safe and profitable?” she said. ❖

— Gabel is an assistant editor and reporter for The Fence Post. She can be reached at rgabel@thefencepost.com or (970) 392-4410.