Most helicopters are not permitted flight into known icing conditions. I have iced up on occasion and in a couple of those instances, I got to find out just how fast a rotor blade can become a very ineffective airfoil and lifting device.
Those events will be blogs for another time. The icing I am talking about here is frost and more particularly frost damage to crops. Frost flying, as its known to helicopter pilots, is an after dark and early morning mission. The flying can be mundane, tedious and very fatiguing. For some pilots, it has been both terrifying and career/life ending, but mostly its repetitive back and forth over a crop in the dark.
It is all dull stuff, till something goes wrong. What can and does usually go wrong happens less than a 100 feet off the ground in the dark over a surface not usually suitable for a safe landing.
Frost flying utilizes the warmer air above the cold surface air and the helicopters rotor system drives the warmer air down onto the orchard fruit,or tomatoes,strawberries or even tobacco. Pick a crop, they are all susceptible to frost damage during their growth cycle. Orchard crops such as citrus or pears, apples are damaged when they mature in the Fall or late winter in the case of citrus. Other crops like tomatoes and strawberries are damaged in the early growth stages which are either spring or winter respectively.
The pilots job remains the same, no matter what time of year. Keep the frost from forming on the crop. In most cases the temperature that the crop gets down to is not as critical as the actual frost which combines with the early morning sun to “burn” the crop. The pilots job is to keep that warmer air flowing and frost from sticking.
If the inversion layer over the field is low enough to be usable and the helicopters can get enough air down to be helpful, crops can be saved. If the weather is a windy cold air mass, crops will be lost from the freezing temperatures only. There is little that can be done to help, when temperatures get and stay below freezing for extended periods of time. When an orange freezes as hard as a billiard ball it is done as an eating orange.
Many farms use helicopters not just to prevent frost damage but to demonstrate to the crop insurance people that everything was done that could have been done. Now pay up!
Something to consider as a small helicopter operator is whether you want to even get involved, in flying of this nature. Yes, there are hazards; flying into fields you have not previously “reconned” is a stupid risk to take in the dark. There are a lot of other things to go wrong as well. A tired pilot can make a mistake at 03:00. Wires and wind machines get impacted. Any mechanical malfunction such as a generator failure from running all those extra lights can get interesting when the world goes from light to barely visible.
I have had hydraulic failures, smoke disorientation and a couple of friends have hit wires at night while frost flying. Remember that altitude is your friend when transitioning from one field to another.
The other hazard is getting paid. If you have flown three nights in a row and your customer/farm owes you for 18 hours of flying you had better be sure that they are going to pay. Getting deposits up front and working with reputable ag. companies will help. However, a farm that did not carry crop insurance and was gambling that they would either not need you, or that your work would be their salvation, may not want to pay after watching a million dollars of crop get plowed under.
If you make a contract to show up and you have a mechanical problem that places your helicopter on the ground on the last night of the frost and your customer loses the crop? What are your chances of getting the money for the nights you did fly? Not good, I’d say! Show up with a bill for several thousand dollars a day after you’re no show, caused the farm to lose thousands more and you are likely to see a more frosty reception than the crop had to endure.