ok so this has been bugging me for a few weeks now and im at my wits end a little bit. running an Agras T40 and we've been getting really inconsistent application rates on the back half of the field. front half looks great on the logs, flow sensor data is clean, everything checks out. then somewhere around the halfway point the droplet size seems to be drifting and im seeing it in the crop response about 5 days later, uneven uptake on a fungicide app we did on winter wheat.

ive already swapped out the nozzles because that was the obvious first step, checked the diaphragm pump, reseated all the connectors i could get to. still seeing it. and the weird thing is it doesnt happen on every flight, its maybe 60% of the time which makes me think its not a straight up hardware failure but maybe something environmental or a settings thing im missing.

the agras assistant software shows everything nominal during preflight which is part of why its so frustrating. anyone had something similar where the logs look fine but the field tells a different story

had almost the exact same issue last summer and it turned out to be a tank baffling problem combined with how i was loading the chemical. when the tank gets below about 30-40% full the liquid was sloshing enough during turns and speed changes to affect the flow consistency. the pump was technically working fine but it was getting inconsistent feed from the tank. started filling to only 70% capacity max and the problem basically went away. might not be your issue but worth ruling out especially if it tends to happen more as you get deeper into a tank load.

what altitude are you flying at and have you looked at your wind data for those flights vs the ones where it worked fine? asking because droplet drift at the field level doesnt always show up in onboard telemetry and the T40 at low altitude is pretty sensitive to even light crosswinds affecting where product actually lands. the logs would look totally clean but youre getting uneven deposition because half the swath is getting pushed laterally. i saw a video from a guy at an ag show talking about this and apparently its more common than people think with larger droplet nozzles