This is a guest post from David Williams, founder of Northwest Drone Pros. David is an instructor in the free course, “Solar + Drones: Site Surveying and 3D Mapping Around Trees“.
Washington is a unique area because we have such an abundance of trees and its not rare at all for both Evergreens and Deciduous trees to reach well over 100 feet, deciduous meaning trees that shed their leaves annually and evergreens of course retaining their leaves and colors throughout the year. If your 2000 dollar drone gets stuck in a 100 foot tall tree not only will it be near impossible to get out if it gets stuck, if it falls it will either not be in great shape or completely destroyed and then of course you wont be able to recover your images. So today I’m going to give you a few quick tips to help you get great imagery while keeping your drone from harm.
First I’ll start with some of the best practices I’ve identified through experience flying around and of course crashing into trees. Here are some of my before flight tips:
- Swap out memory cards If you’re surveying multiple locations in a day and you crash into a tree or lose the drone with the previous surveys images on board you’ll have to return to the survey location again and get the images. It could be foggy or raining when you return so I’d just as soon have multiple memory cards, they’re cheap.
- Have spare props (they’re about 30 bucks depending on which model your flying, if you hit something and damage the props at a location and don’t have spares you’ll be out of luck on getting the survey done that day and they don’t sell props at the corner store so most likely you’ll be going on amazon and waiting a couple days to drive back to the location which can be far at times.)
- Prop Guards I recommend prop guards, they are about 30 dollars and Protect people and objects from spinning propellers, improving your flight safety. They also can prevent minor collisions such as a tree branch from bringing your drone down.
- Backup Drone- I always bring a second drone because you never know if there will be an equipment failure or the drone software will require a timely update while on-site. Personally I use the Phantom 4 as my back up to the Mavic 2.
- GPS Mode Don’t take off until you are in GPS Mode. I fly exclusively in GPS mode and with DJI drones you’ll know you’re in GPS Mode because the upper left portion of the display will turn green (as seen in the slide) and it will say GPS on the display once the drone has locked in which I believe requires around 9-12 satellites which the drone uses to position itself. The drone will then automatically lock-in its return to home setting which means if battery life gets low or there are communication issues it will return to where it took off from. I never fly in atti mode which is the default mode the drone will go to if there are not enough satellites for GPS Mode. Atti Mode is short for Altitude Mode, where the drone will maintain a specific altitude but not position. That means the drone will remain at the same height but drift around in the wind, I do not recommend this around swaying 100 foot plus trees.
- RTH Setting-Make sure your RTH or return home is set higher than the surrounding trees. The way return home works is when the battery life gets low or the drone loses communication it will attempt to go back to where it launched from. It first will elevate to a height set by you then move horizontally towards home. If obstacle sensing is off the drone could raise up to its RTH height of 80 feet then start going home, but if the trees are 100 feet then its going to crash. If obstacle sensing is on, there is the potential it may sense the tree and stop but the battery life is so low that it cant make it home and falls out of the sky.