so this is embarrassing but figured id post it anyway because maybe someone can help me figure out what happened or at least make me feel less dumb about it. was doing a commercial flat roof inspection yesterday, big warehouse type building maybe 12000 sqft, and i had a whole grid pattern planned out in Litchi. everything was going fine until i got to the section with the big HVAC clusters on the northeast corner.

compass went haywire - i could see it in the telemetry - and the drone started drifting even though i was in GPS mode. tried to take manual control and i think i overcorrected because it clipped one of the curb mounted units pretty hard. props are toast, camera gimbal is making a grinding noise now. drone flew back home which is the one saving grace.

im pretty sure it was magnetic interference from the HVAC compressors but honestly wasnt thinking about that when i planned the flight. do you guys keep a higher AGL when flying near that equipment or do you switch to attitude mode or what

oof yeah HVAC clusters are notorious for this, especially the big 3 phase compressor units. i usually add a buffer and fly at least 4-5 meters above any rooftop mechanical equipment and do those sections manually rather than trusting a pre-planned mission. attitude mode is actually fine if youre comfortable with it but most people arent and that tends to make things worse in a panic situation. glad it came home at least. gimbal damage is annoying but usually fixable - check if its just the ribbon cable or if the motor itself took a hit before you assume the worst

this exact thing happend to me on a school roof last spring. different drone but same story - compressors everywhere and my compass just started spinning out. what i do now is scout the roof on google maps first and if i see heavy mechanical equipment i plan my orbit higher and drop resolution rather than fly low and risk it. also started doing a quick compass calibration on site before every commercial roof job even if the app says its fine. probably overkill but it makes me feel better. hope the repair isnt too expensive