As an Hawaii commercial drone pilot I’m frequently called upon to fly drones during fairly high winds. In Maui we usually experience winds that are in the 20-to-30 knot range with gusts that can reach the 30’s , and occasionally 40’s. When I’m assigned an aerial media capture job in wind , I must assess and decide whether it is safe to fly without risking a drone, flying in a way that is out of control or harming anyone. It is clear that the decision to issue a “no fly” call is not the best option and often results in an immediate loss of money in the rapidly changing industry of commercial drone services. Most of the time, high wind flying takes place over waters (shark plagued sea water, to be precise!) which increases the risk and complexity of the operation. In addition, as you know losing a drone into the ocean’s big blue kind of makes it impossible to get a replacement via insurance such as DJI Care Refresh, unless you can retrieve the drone to send it back to DJI. The good news is that you rarely encounter obstacles in water and the transmission of images is usually not interrupted due to interference from objects. The problem is that in the event of a problem, you’ll need to travel the length of No Man’s Land before you even get a chance at recovering your drone.
To prepare for a planned drone shooting, for example kitesurfing as an example, I do several things. Before I do that, I verify whether the text invoicing location I’m to be flying at is in a “green zone”. This means that it’s not within an FAA no fly zone, isn’t less than 5 miles from an airport. Additionally, it it has a legal launch and land area within visual sight distance of the drone’s area of operation. Then I’ll make sure that I have the permits, insurance as well as any FAA clearances needed for the task. Once the location is cleared I conduct a weather check before shooting, conduct a pre-shoot survey, and draw up plans for shooting as well as a plan to handle emergencies based on the current weather conditions and topography of the coastline. In the end, I arrange for my assistant to shoot as a visual spotter is mandatory by law and highly recommended for anyone who wants to push the limits of a drone’s flight capabilities.
What I’m looking for when I go to check the weather is if there is going to be sun (drone shots require sunlight) and how powerful the wind will be. The gust factor of the wind is a biggie. A lot of variability in the wind is detrimental to the drone’s flying experience. It can cause the drone to pitch and roll considerably more than a steady winds. Depending on the wind speed I will determine if the drone is capable of handling the highest limit of the wind prediction. The direction is also important. Offshore winds present a far greater risk than Onshore winds when flying over water for obvious reasons. Finally, I think about the conditions when determining not only if I’m able to fly, but also the distance, what is the subject doing, if there are other obstacles, the range of my drone and what is a safe altitude. Kitesurfing offers the ability to move quickly at the end of 30 meter lines which means that any shots less than 100 feet should take into account this movement and related risk.
When shooting day arrives, you’ll need to evaluate the conditions for wind and weather (don’t be caught in the rain) and then decide whether for flying, or whether fly. I prefer to perform this prior to clients or other elements of production being present so that I can make the decision without being influenced by any bias. If it’s a “go” situation I fly my drone using normal GPS mode up to about 10 feet and see whether it stays in place. If it’s cold in the area where you launch be sure to launch from the ground because the drone will flip before taking off. If you’re able hover on the ground without losing any ground, then try to fly up to your maximum shoot altitude and then test the wind speed. If the wind starts to take over your drone and it starts to drift away, bring it back down to a lower level and try to recover it. If it is too windy for you to retrieve your drone in GPS mode you can attempt switching on “sport mode” (DJI Mavic Pro and Phantom 4 series) and fly it back. You should be comfortable in switching between and flying in sport mode prior to flying. When your drone is drifting away , it is not the best moment to review the set-up menu to the very first time. If sport mode isn’t an option and you have obstacles around you can use these as windbreakers. If you’re flying the drone towards you in full speed but it is still blowing over the drone, you could slide behind trees, buildings barriers, even mountains to enter the more stable conditions. Although obstacles can increase wind variability I have found a combination of lowering the altitude and moving behind objects that slow the wind could get you out of the majority of situations and at least let you get the drone down to the ground , not into the water. If the wind is blowing off from shore and into the sea you have few options for recovery , and the wind might be as strong at 10 feet from the sea as up 100 feet. Extremely strong and (typically) violent offshore winds present the highest danger that your drone could be lost above water and must be approached with extra care.
Remember to stay safe and not to regret it. Do not put your drone in an unfixable situation. Have multiple backup plans in case of emergency. Be aware of your equipment prior to flying over or in the wind. Know your drone’s limits when you’re flying through water, including distance and time limitations as well as the effects of wind on relative speed vs . surface speed. For example, if your drone can fly at 25 MPH top speed and it is gusting 15 to 20 mph, it could fly downwind at the speed of 45 Mph but may only be able go upwards at 5Mph. If your drone travelled 1 mile downwind, ensure that you have enough batteries to allow it to return upwind at 5 Mph which , based on my calculations, would take about 12 minutes. Also “sport mode” increases speed but reduces battery life. Try to keep your drone from flying on empty. Performance can be lower than you’d expect when your battery becomes depleted and will definitely increase the stress when you’re in the single digits, but you’re not back to shore.