so ive been doing tower inspections for a cell carrier for about 3 years now, mostly rope access and occasionally man lifts for the shorter structures. company started asking about whether we could start doing drone inspections instead because the liability costs for climbers are getting insane. im not totally against it but i have some real questions about whether the image quality is actually good enough to replace a physical inspection for things like connector corrosion, antenna mount hardware, cable management issues, that kind of thing.

im currently looking at the Zenmuse H20T on a M300 but honestly the zoom range is what im trying to wrap my head around ? like at what working distance are you actually getting useful resolution on a 3/4 inch bolt that might have stress fracturing. has anyone here actually done this for a carrier and had their deliverables accepted by the structural engineers on the other end? thats the real question. not just can you get pretty pictures of a tower, but does it actually pass muster professionally.

also curious if anyone has run into FAA issues doing this near active antenna arrays, i know theres some concern about RF interference but ive heard mixed things

yeah we switched about 18 months ago for a regional carrier here in the midwest, running the M300 with H20T exactly like youre describing. the 23x optical zoom is genuinely good enough for most hardware inspection once you figure out the right standoff distances ? we usually work between 5 and 8 meters for close detail shots and the engineers have been accepting the reports. we use a structured shot protocol now, same angles every time, so theres consistency across inspection cycles which the clients actually love.

the RF interference thing is real but its also kind of overstated in my experience. weve had some compass wonkiness near the top of active CDMA towers but the M300 handles it better than anything else ive flown. you do want to do a thorough pre-flight compass cal away from the structure. where it genuinely gets sketchy is if youre working around some of the older broadcast towers with high-power AM arrays, thats a different animal entirely and i wouldnt push it.

the structural engineers sign-off question is the right one to be asking though. get them involved early, like before you even finalize your shot list. we had one firm that wanted specific oblique angles we hadnt planned for and it saved us a re-flight.

dont have tower experience specifically but we do a lot of high-voltage transmission line inspections and some of the same questions come up. the zoom resolution thing is something you just have to test yourself with your specific deliverable requirements ? what the engineer is looking at on a lattice tower connector is different from what a line crew needs to see on an insulator string, so i cant give you a direct answer there.

one thing i will say is that the hybrid approach seems to be where most serious operators land. drone does the initial condition assessment and flags areas of concern, then you send climbers to those specific spots only. cuts rope access time way down and the liability math starts working in everyones favor pretty quick. not sure if your carrier client would go for that workflow but its worth floating