As an Hawaii commercial drone pilot based in Hawaii, I’m often requested to fly drones in extremely high winds. In Maui there are typically winds in the 20 knot range with gusts that can reach the 30’s and sometimes 40’s. When I’m assigned an aerial media capture task with wind gusts, I must do a risk assessment and decide whether it is safe to fly without risking a drone, flying off the beaten track or injuring anyone. Of course, an “no fly” call is not a good idea and typically results in an immediate financial loss in the fast paced industry of commercial drone services. The majority of times, high-wind flying happens on water (shark infested salt water to be precise!) which increases the risk and difficulty of the task. Furthermore, as you be aware, dropping a drone into the ocean’s big blue kind of negates your ability to get a replacement via pay by QR code insurance such as DJI Care Refresh unless you have the ability to recover the drone to return it to DJI. It’s good to know that you rarely encounter obstacles in water and the transmission of images is seldom interrupted due to interference from objects. The problem is that if you have a problem you need to first traverse some distance through No Man’s Land before you even get a chance at returning your drone.
To prepare for a planned drone shot, such as kitesurfing as an example I do a variety of things. First , I determine if the location I’m going to fly in is a “green zone”. This means it is not within an FAA no-fly zone, isn’t within 5 miles of an airport. Additionally, it it has legal land and launch area that is within sight distance of the drone’s area of operation. The next step is to make sure that I have the insurance, permits, and any necessary FAA approvals needed to complete the task. Once the location is cleared I look up the weather in the area before shooting, conduct a pre-shoot survey, and create plans for shooting as well as a plan for emergencies based on prevailing weather conditions and topography of the coastline. Then I schedule my assistant to shoot, as a visual spotter is legally required and highly recommended when pushing the limits of drones’ flying capabilities.
What I’m trying to find when I check the weather is whether there will be sun (drone shots need the sun) and how strong the wind will be. Also , the gust in the winds is crucial. There is a lot of variation in the wind is detrimental to the flight experience and could make the drone roll or pitch significantly more than it would with a steady winds. Based on the wind speed I will determine if the drone is capable of handling the highest limit of the forecasted wind. It is important to know the direction. Offshore winds present a far greater danger than winds from Onshore when flying on water for obvious reasons. In addition, I look at the conditions when determining not only if I can fly, but also what distance I can fly, what’s the person doing, are there any other obstacles, how far my drone can fly and the safe altitude. Kitesurfing is an extremely swift kite at the end of the lines of 30 meters which means that any shots less than 100 feet should consider this type of action and associated risk.
When shooting day arrives, you’ll need to assess the actual conditions for wind and weather (don’t be caught in the rain) and then determine whether you want to fly or not to fly. I like to perform this prior to clients or other production elements being present so that I can make my choice without bias. If it is an “go” situation I fly my drone using normal GPS mode up to 10 feet to see whether it is able to stay on the ground. If it’s windy in your launch area make sure you don’t launch off the ground, or the drone will flip before it takes off. If you can hover on the ground without losing any ground try flying up to the maximum altitude for shooting and then test the wind speed there. If the wind begins to overwhelm your drone and it begins to drift away, take it back down to a lower elevation and try to get it back. If it’s too windy to recover your drone in GPS mode you can attempt switching to “sport mode” (DJI Mavic Pro series and Phantom 4 series) and fly it back to you. Make sure you are familiar when switching to and flying in”sport mode” prior to taking flight. As your drone drifts off isn’t a good moment to review your set-up menus in the beginning. If sport mode is not an option, and there are obstacles around you can use to break up the wind. If you are flying the drone back towards yourself in full speed but it is still blowing over the drone, you can fly it behind buildings, trees barriers, or even mountains to reach the more stable conditions. While obstacles can cause wind variability , I’ve observed that a combination of lowering your altitude as well as gaining access to things that slow down wind will get you out of most situations and at least permit you to lower the drone down to the surface and not under the water. If the winds are blowing away from shore and towards the ocean, you have few alternatives for recovering and the wind could be as strong at 10 feet from the water as it is 100 feet up. Strong and (typically) violent offshore winds are the most likely risk in losing the drone above water , and should be approached with extra care.
Remember to be secure, not to be sorry. Do not force your drone into an unrecoverable scenario and keep multiple backup plans for the event of an emergency. Be aware of the equipment you are using before flying into wind or over water. This includes time and distance limits as well as the effects of wind on speed and surface speed. For instance if your drone flies 25 MPH and it is gusting 15 to 20 Mph , it may fly downwind at an average speed of 45 Mph. It may be able to fly forward at 5 Mph. If your drone went a mile downwind make sure that you have enough batteries for it to go back upwind in 5 Mph, according to my calculations, this would take roughly 12 minutes. Also “sport mode” increases speed but it also reduces battery lifespan. Don’t forget to avoid flying your drone on empty. Performance can be lower than anticipated when the battery gets low and it is a sure sign that stress levels are higher when you’re down in the single digits but not back on the water.