Spray drones live in the worst environment imaginable for machines: corrosive chemical, dust, vibration, heat. Assume preventive maintenance, not reactive.
Daily pre-flight (5 minutes, every single day)
- Props: cracks, chips, delamination — replace as a set, never one blade
- Motors: spin freely, no grinding, no play in the bearing
- Arms/frame: hairline cracks at joints, all fasteners tight
- Tank/lines: no leaks, screens clean, atomizer discs unworn
- Battery bay contacts: clean, dry, no corrosion
- Firmware current; RTK/compass calibrated if prompted
- Radar/obstacle sensors wiped clean (chemical film blinds them)
End of every spray day
- Flush the liquid system with clean water + appropriate tank cleaner.
- Wipe the airframe down — dried chemical is corrosive and hides cracks.
- Pull and rinse screens; check atomizers.
- Cool, then storage-charge packs you won't use tomorrow.
- Log hours, anything replaced, anything odd.
Periodic service (by hours)
- ~25 hours: inspect motor bearings, check all fastener torque, deep-clean pump and lines.
- ~50 hours: replace pump diaphragms/tubing per manufacturer, rotate/replace props proactively, inspect wiring for chafe.
- Seasonal: full teardown-clean, replace all screens/seals, battery capacity test and retire the weak ones, firmware review, then a full water calibration before the first job.
The wear signs that mean "stop"
Vibration you can feel in the controller, a motor that's hotter than its siblings after landing, a prop with any crack at the root, a pump that won't hold rate, or a frame joint with movement. None of these get better with one more field.
Intervals are typical — your manufacturer's manual governs. Records: FAA recordkeeping.
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