Chris512
 lvl.1
United States
Offline
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I fly only with Litchi because I need to develop precision flights in the office for aerial survey work and cannot afford the time to fly the flight first to record waypoints with DJI Go. I plan all my flights for VLOS and to always maintain contact with the aircraft. I would consider it irresponsible on the pilot's part to deliberately fly the aircraft out of range and VLOS using autonomous flight.
That being said, there is several times I have been flying waypoints with Litchi and lost contact with the aircraft for a few moments due to planning errors in the flight, usually involving trees scattering the signal. The trees between me and the aircraft being bigger and taller that what the terrain view showed when planning the flight. The app announces that signal has been lost and it draws a line from the aircraft's last known position to Home, but the flight continues, as uploaded to the flight controller. It may be for only 10 seconds, but I typically have to turn the controller off, then turn it back on to re-establish contact with the aircraft after it flies past the trees.
I have had the flight abort a few times, and RTH actually trigger, when using certain modes where signal contact is required to send commands to the aircraft during the flight (such as using Timer Mode with the camera instead of Interval Mode). The Litchi guy said the DJI sdk is not particularly friendly to work with and they haven't nailed down the exact reasons why RTH is sometimes triggered on waypoint flights when it shouldn't be. I actually do think it would be a good thing if RTH was triggered anytime signal is lost for more than about 30 seconds, regardless of whether or not it is a waypoint mission. There is no reason, to my way of thinking, that anybody has any business flying an aircraft while deliberately being out of range of direct control of it.
The flight in question is actually a round-trip flight. Waypoint 1 and waypoint 3 are the same. It looks like the aircraft is being flown at 625 feet altitude (illegal in the US), out to a distance of a little over 2 miles. You may or may not be able to maintain contact with the aircraft that far away at that altitude. Judging by the aerial view of the flight path I would say not because you likely have trees close to home base that will scatter the signal due to the angle of incidence required for direct LOS for UHF. I quite regularly fly out to a mile on flat open terrain doing aerial surveys at 328 feet altitude, without losing either control or telemetry signals with a P3S. But in my experience, that is about the limit for the P3 Standard with 100 mW radios.
Looking at the flight path with the aircraft flying over residential areas there is no way, no how, I would attempt that flight. If the aircraft goes down anywhere during the flight you will likely never recover it, and hopefully somebody doesn't get hurt in the event it has a forced landing.
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lvl.2
lvl.4
