Regarding the mission plan, I considered your recommendation of flying a cross-hatch pattern but, because I realized that I was going to have to fly a test mission regardless, I reasoned that I wouldn’t learn anything if I flew a very conservative pattern to be sure things would work. My goal was to win this project as a repeat customer (inventory every 3 months on a number of sites - this one being by far the most challenging) so I wanted to fly the quickest mission with a reasonable chance of success. I intentionally flew in full sunlight because I figured it would, again, be the worst case test for future missions. At 1/500 shutter and 4 mph, I reasoned that I had some wiggle room for a slower shutter on future missions in cloudy conditions. Plus, cloudy conditions are generally better for mapping.
The hardest part was setting the geofence. I set the initial draft of the geofence on the desktop DD app before going to the field. Once in the field I got LAANC clearance using AirMap, then went to the Go4 app for DJI clearance to fly. The site was in an area that was not fully restricted (not within the airport “bowtie”) but that allowed flight with an acknowledgment and release agreement.
Here I learned something that many might find valuable. DJI’s release process is very obscure: a pop-up screen says something like, “take-off not allowed, you must obtain release from DJI” or words to that effect. I spent the next 30 minutes sifting through endless DJI Airspace pages looking for the clearance release with no luck. Finally, in frustration I went back to the “no take-off” pop-up and ignored it, pushing both sticks down and in to start the motors. Hosia!! The release form popped right up! I checked the box and was good to go. BIG LESSON HERE: don’t believe the pop-up that says the bird won’t fly! Try it anyway and yee shall be rewarded!
I got the bird in the air and opened the DD app, then carefully flew along the edge of the geofence while visually checking the clearance to the adjoining interstate and trees. When I got as close as comfortable I adjusted the geofence to match the indicated position of the drone on the display. Obstacle avoidance was left on for obvious reasons. Finally, once clearance was confirmed, I landed, installed a fresh battery, and flew the mission without incident.
The 50’ AGL requirement was a given. I chose 85/80 overlap and 4 mph as a best guess at what might work vs. the amount of time the mission would take (actual flight time was about 1 hour - 3 batteries - 4 acres). I figured If the mission worked with these parameters, I could live with not chasing further time savings.
Alas, I didn’t win the project. My understanding is that the previous pilot that had been flying the mission had been flying with no questions ask of him (ie: probably unlicensed and uninsured). I think he got cold feet when DJI implemented their new “bowtie” clearance scheme and he had begun renting a ground based laser scanner to complete this site. I assume my price probably was used to get him to undercut his laser scanner price to complete the work. So be it, fortunately, I am not hungry enough to need to chase unprofitable work.
Again, let me know if questions. I learned a lot on this one along with gaining a few more gray hairs.