by Hal Davis
WisDOT Bureau of Aeronautics
With autumn upon us, and winter fast approaching, it may seem like an odd time to talk about farming. However, these next few months between farming seasons are the perfect time to evaluate farming operations on your airport.
For those of us who have flown around the Midwest, you’ve probably seen first-hand that farming is fairly common on airports in this part of the country. In Wisconsin, about half of our airports use airport land for farming purposes.
Renting airport land to local farmers certainly has its benefits. First, it can be a source of revenue to help offset operating expenses for the airport. Secondly, it reduces the amount of undeveloped green space that an airport would otherwise need to maintain. On the other hand, if not controlled properly, on-airport farming can easily cause more harm than good. In order to maximize the benefit and minimize harmful effects of on-airport farming, two important considerations need to be made.
The first is “location.” Many unpaved areas on airports serve vital aeronautical purposes. To the untrained eye, however, these areas look like ideal farming locations. It’s important that these critical areas be identified to ensure that farming activities do not conflict with the aeronautical purposes they serve. Specifically, Federal Aviation Administration (FAA) Advisory Circular 150/5300-13A prohibits farming activities in object-free areas. Object-free areas provide a buffer of clear land around runways, taxiways and aprons in the event an aircraft leaves the pavement. They also ensure adequate wingtip clearance for larger aircraft.
Farming activities must also be kept clear of critical airport infrastructure. If allowed too close, crops can obscure lights and signs or may disrupt navigational aids or weather stations. Airports with an instrument landing system (ILS) must be especially careful to keep ILS critical areas free of farming activities. Under no circumstances should any farming activities occur in the localizer or glide slope critical areas or activities occur in the localizer or glide slope critical areas or the approach light area.
In addition, inviting the use of farm equipment near critical airport infrastructure increases the chances of accidental damage. Finally, tall crops and farm equipment may obscure the view of pilots and air traffic control personnel.
Airports with intersecting runways should avoid planting any crops within the runway visibility zone. This area requires direct line of sight between any one point five feet above the runway centerline to any point five feet above the crossing runway centerline within the zone. Because most farm equipment is taller than five feet, there are very few circumstances in which the terrain or farming methods would allow any farming to occur within the runway visibility zone. In addition, airports with air traffic control towers should ensure that crops and farm equipment do not block the tower’s line of sight.
The figure to the right illustrates the general locations of object-free areas, ILS critical areas, runway visibility zones and other areas where farming activities are prohibited at a generic airport. For the dimensions and locations of these areas at your specific airport, please reference your airport layout plan or contact the Wisconsin Bureau of Aeronautics (BOA).
Secondly, an airport must consider the effects farming activity may have on local wildlife.
According to the Federal Aviation Administration (FAA), most, if not all, crops can attract hazardous wildlife activity during some phase of production. Therefore, airports should take great care in determining which crops are permissible on the airport. In general, crops, which produce a food source for local wildlife, should be avoided. This includes most grain crops such as corn. In some cases, airports may require their farmers to utilize special cultivation techniques or modify normal farming activities to mitigate the attraction of hazardous wildlife. For example, an airport may require a farmer to plow under any waste material within 24 hours of harvest. In addition, airports should monitor farming activities to ensure standing water is not created or contributed to which can also attract hazardous wildlife to the airport environment.
Throughout the farming operation, the airport should remain vigilant of increases in hazardous wildlife activity. If an increase is identified due to the farming activity, the airport should immediately take steps to reduce the hazard or terminate the farming activities altogether. Of course, executing this type of control over the farming activities requires a formal agreement.
Any farming activities should be conducted under a written lease agreement between the airport and the farmer. This is to ensure the airport is properly protected and retains sufficient control over airport property. Like any other lease agreement, a lease for farming activity should establish the rental fee, duration of the agreement and limitations on how the land will be used.
FAA requires the airport to be compensated at a fair market value rate for any non-aeronautical use of airport property. Farming activities are no exception. Fair market value is dictated by the local value of leased farmland. While there may be multiple methods of determining fair market value, perhaps the best method is to competitively bid the lease. This method guarantees the airport receives the maximum compensation given the local market. It’s also important to note that all revenue generated from farming leases must remain with the airport to be used exclusively for airport purposes.
As with most lease agreements on the airport, the shorter the term, the better. This helps the airport maintain short-term control over farming activities. Not only does this make good business sense, but preserving rights and powers is a required federal grant assurance. Ideally, farming leases should be renewed annually to provide the airport with maximum flexibility to adjust the rental rate and reassess the impact of the farming on airport operations and development. For further control, the lease agreement should also contain an escape clause in case the leased property is needed prematurely for airport development or the farming activity has an unexpected adverse effect on airport activity. It is also important that the lease specify limitations and expectations related to the use of the airport property for farming.
For instance, the lease should specify the exact location of the farming and which crops are allowable. It is also important that farm equipment be managed properly when on the airport. The lease should detail the access route and security requirements. Additionally, the lease should address the temporary parking of equipment and the storage of harvested crops on the airport.
Finally, the lease should protect the airport in the event farming activity causes damage to airport surfaces. As previously mentioned, farming equipment can cause accidental damage to airport infrastructure and can also leave behind ruts or spread foreign object debris (FOD) onto airport pavements.
Even if the farming operation at your airport has gone on for decades without incident, there’s no harm in taking this time to re-evaluate its impacts on the airport.
For example, it is very common for farmers, whether on purpose or by accident, to encroach into safety critical areas, especially if they are not permanently marked. As I’ve discussed, there are many considerations to be made when evaluating on-airport farming. Luckily, the Wisconsin Bureau of Aeronautics is here to help. We can provide guidance on siting the farming activities, the effects the farming may have on wildlife and can even provide a template for the lease. If you have any further questions or would like assistance, please call me at 608-267-2142 or email: howard.davis@dot.wi.gov.