so this has been bugging me since this morning. we were doing a visual inspection on a 200ft monopole, standard stuff, client wanted documentation of the antenna mounts and any corrosion on the climbing pegs. ive done probably 40 or 50 of these no problem.

i was orbiting at about 180ft maybe 15 feet lateral clearance from the structure and somewhere around the 3rd pass the aircraft just started drifting toward the tower. not a gust, the air was pretty calm, it corrected itself but only after i went to manual and pulled out. on review the telemetry shows a big compass error spike right when it started drifting.

i know towers mess with magnetometers, ive always done my compass cal away from the site before flying. but this was worse than anything ive seen before. talked to another operator who said some of the newer 5G equipment they're installing throws off interference in ways that older antennas didnt. anyone else run into this? starting to wonder if i need to be in full atti mode from the start on these or just tighten up my RTH settings so it doesnt try to do anything autonomous near the structure.

yeah the 5G stuff is genuinely worse, specifically the active beamforming arrays some carriers are putting up. the electromagnetic environment around those is just different than a passive panel. ive started treating any tower with visible massive MIMO arrays as a no-GPS zone from the moment i arrive, do a visual check of the equipment before i even power up the drone. if i see that type of hardware im flying in atti the whole job, closer to 20-25ft clearance minimum and always with a spotter.

the compass spike you're describing sounds exactly like what happens when the aircraft flies through a null or a hotspot in the field. your instinct to pull manual was right, the FC just gets confused and starts trusting bad compass data over GPS positioning.

dont quote me on this but i read somewhere that some operators flying around broadcast towers have gone to redundant GPS setups or switched to platforms with dual IMU configs specifically becuase of interference issues. not sure what aircraft youre on but might be worth looking into if youre doing this regularly for clients. one incident is one thing but if it happens again on a busy site that could go real bad real fast.