BEST WAYS FOR DRONES

As an Hawaii based commercial drone pilot I am regularly required to fly drones when there is relatively high wind. Here on Maui the typical wind is in the 20 knot range with gusts into the 30’s and sometimes 40’s. Every time I’m assigned an aerial media capture job with wind gusts, I must make an assessment and determine whether it’s safe to fly without risking the drone, flying too fast or causing injury to someone. Obviously the decision to issue a “no fly” call is not a good idea and typically results in an immediate financial loss in the fast paced world of commercial drone services. A lot of the time, this high-wind flying takes place on water (shark plagued sea water, to be precise!) which increases the risk and complexity. In addition, as you be aware, dropping a drone invoices by text into the ocean’s big blue kind of ruins your chances to get a replacement via insurance, such as DJI Care Refresh, unless you are able to retrieve the drone and send it back to DJI. The good news is you typically don’t have to contend with obstacles on water, and the transmission of images is usually not interrupted due to interference from objects. The issue is that in the event of a problem, you must first travel the length of No Man’s Land before you even have a shot at returning your drone.

To prepare for a scheduled drone shot, such as kitesurfing as an example I take a number of steps. First I check to see whether the location I’m to fly at is in a “green zone”. This means it is not located in an FAA no-fly zone, not less than 5 miles from an airport. Additionally, it also has a legal launch and land space within the visual view distance from the drone’s field of operations. The next step is to make sure that I have the insurance, permits and FAA clearances necessary to perform the job. After the location has been approved, I verify the weather conditions in the area before shooting, conduct a pre-shoot survey, and sketch out an outline of the shooting plan as well as a plan for emergencies based on prevailing wind direction and coastline topography. 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 drones’ capability to fly.

What I’m trying to find when I look up the weather is if there will be sun (drone shots require the sun) and how strong the wind will be. The gust factor of the wind is an important factor. A lot of variability in the wind really degrades the experience of flying and may result in the drone having to roll or pitch significantly more than steady winds. Based on the speed of wind I determine if my drone can handle the upper limits of forecasted wind. Also, direction is crucial. Offshore winds carry a more risk than Onshore winds in the event of flying over water due to obvious reasons. Also, I take into account the environment when deciding just if I am able to fly but also in what range, what’s the subject doing, are there other obstacles, the range of my drone and what is a safe altitude. With kitesurfing you have an extremely swift kite at the end of 30 meter lines which means that any shots less than 100 feet have to account for this action and the risk that comes with it.

When shooting day arrives, you’ll need to look at the actual conditions of the wind and weather (don’t get caught by rain) and then decide whether of whether or not fly. I like to do this prior to clients or other production aspects arriving so that I can make the decision without being influenced by any bias. If it is a “go” situation I fly my drone using normal GPS mode up to 10 feet to see whether it stays at a certain point. If it’s really windy in the area you are launching from, make sure you don’t launch off the ground or the drone will flip before it takes off. If you can hover in place without losing ground, try flying to your maximum shooting altitude and observe the wind speed there. If the wind starts to take over your drone and it starts to drift away, bring it back to a lower altitude and try to get it back. If it’s too windy for you to retrieve your drone while in GPS mode you can try switching in to “sport mode” (DJI Mavic Pro and Phantom 4 series) and fly it back to where you. Make sure you are familiar in switching between and flying in sport mode prior to flying. While your drone is drifting away is not a good time to go through the setup menu when you’re first starting. If sport mode isn’t an option and you have obstacles around , you could use these as windbreakers. If you’re flying your drone in the direction of your own in full speed but it is still blowing over the drone, you could slide behind trees, buildings or barriers and even mountains to get into an environment that is more stable. However, obstacles can also increase wind variability , I’ve observed that using a combination of dropping your altitude and getting behind objects that slow the wind can help you get out of the majority of situations or at the very least enable you to bring the drone down to the ground and not in the water. If the winds are blowing away from shore and towards the ocean, there are few options to recover and the wind may be just as strong 10 feet off the ocean as at 100 feet up. The strongest and (typically) violent offshore winds carry the greatest risk for losing drones over water and must be approached with a higher degree of care.

In the end, just remember to stay safe and not sorry. Don’t push your drone into an unfixable situation. Have various backup plans to deal with any eventual emergencies. Know your equipment well before flying over or through water, such as distance and time limits as well as the effects of wind on relative speed vs . surface speed. For instance if your drone flies 25 MPH and is speeding up 15 to 20 Mph it may be able to fly downwind with 45 Mph, but it may be able go upwards at 5Mph. If your drone travelled for a mile, be sure you have enough battery to allow it to return upwind in 5 Mph, that would, according to my calculations, take approximately 12 minutes. Also “sport mode” increases speed but reduces battery life. Try to avoid flying your drone while empty. It is possible to fly less than what you’d like when the battery gets low and it certainly increases stress levels when you’re in the single digits and not yet back on the water.

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