so this is kind of embarassing to post but maybe someone can help me figure out what happened. was doing a commercial flat roof inspection on a big box retail building, probably 80,000 sq ft footprint, looking for ponding water and membrane damage for an insurance adjuster. had done maybe a dozen of these before with no issues.

about 15 minutes into the flight the drone just... stopped responding. not a gradual thing, it was flying fine and then the connection dropped and it didnt RTH, it just went down somewhere on the roof. we're pretty sure it landed somewhere on the roof itself because we didnt see it fall and the building manager wont let us up to look without a whole access request process that takes like two weeks apparently.

im running a Mavic 3 Enterprise and the last telemetry I had it was hovering around 40ft AGL. battery was at like 55% so that wasnt it. the only thing i can think of is there was a LOT of HVAC equipment up there and maybe something interfered? there were some big rooftop units running and i remember seeing the EMI warning briefly before connection dropped but i didnt think much of it at the time

anyone dealt with this before on industrial rooftop work

yeah that EMI warning shouldve been a bigger red flag honestly. large commercial HVAC systems and especially the variable frequency drives inside them can absolutely wreck your control link if youre flying close overhead. ive had compass errors go crazy on industrial rooftops before and learned to either fly higher above the equipment or keep standoff distance. the mavic 3 enterprise is generally pretty solid but its not immune to that stuff.

on getting the drone back - most building managers will let you up faster if you frame it as a safety issue rather than a retrieval thing. like technically an unknown object on a commercial roof is a liability for them too so sometimes that angle moves things faster than just saying hey i need my drone back

this is actually why i switched to doing pre-flight walkarounds on the ground level before any industrial roof job, just trying to spot how much HVAC is up there and where its clustered. doesnt always help because you cant see everything but it at least gives you an idea of where the interference risk zones might be. also started planning my flight paths to keep altitude higher over equipment clusters and only descend for close inspection passes once im clear of that stuff.

hope you get the drone back. two weeks is brutal, i had a similar access situation with a warehouse once and ended up just eating the cost of a new drone because the client was being difficult about it. not ideal.