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DJI Agras T40 Preseason Checklist and Maintenance Guide


The DJI Agras T40, since its launch at DJI AirWorks in Las Vegas in October 2022, has become the spraying drone of choice for both farmers and custom spray service providers, proving to be an indispensable asset for precision agriculture. For many T40 owners, we are about to begin our second season with the Agras T40 as our daily driver. Therefore, it's essential for agricultural drone operators, farm managers, and custom spray drone service providers to perform preseason maintenance to ensure that their T40 is at the peak of its performance. Read on to see DJI Agriculture's essential T40 preseason maintenance tips to start the 2024 spraying season on the right foot.


Why a Preseason Checklist is Essential


A preseason maintenance check is not just proactive; it's a strategic move. The situation you want to avoid at all costs is arriving at the field, pressed by a tight schedule, only to find that your T40 has an issue that could compromise its performance or even sideline it for the day. Ensuring that your T40 and its components are in top condition before you hit the fields can prevent costly downtimes and potential accidents. By laying down a rigorous preseason checklist, you're fortifying your agricultural operations against the uncertainties that come with technological devices that are exposed to the harsh conditions of the farming environment.


Preseason Maintenance Checklist


Here are some essential steps you can perform to make sure your T40 is ready for the season:




The arms of your T40 are its supporting pillars. They handle the drone's weight and are critical for stability.


To start, open the arms up and lock them into place. If the arm glides from the closed to open position with little to no effort, this can be tightened with a 16 mm socket wrench


Next, verify that the arms are securely fastened. Grab each arm at the motor base and try to wiggle it. Loose arms are not just a flight risk; they can also throw off the drone’s calibration, affecting the precision of its spraying pattern. If an arm is loose, you will need a 16 mm socket wrench to tighten the nut.


This is a good time to also check the arm safety locks and make sure they are working correctly - when locking it you should hear it snap into place. If an arm lock is too loose, it can open by itself which is not good. Conversely, if the lock is too tight, it can be not only a hassle to lock/unlock it, but also potential cause for micro-fractures within the carbon fiber of the arms, which can lead to a larger fracture mid-flight. The locking handle tightness can be adjusted with a small 6 mm crescent wrench. With the handle open, there is a hex-shaped rod within the handle that can be adjusted with the wrench.


To finish the inspection of the arms, check for any surface damage. Even superficial cuts and abrasions can be weak points, potentially leading to failure in high-stress situations.


Motors and Props


Start by opening up the pair of props so they are close to 180 degrees, or a straight line. Notice the tightness of each prop and ensure the prop adapter screws have not become loose over time. These are really the only screws that need attention within this area.


Like the arm tightness above, there should be some resistance or tightness when opening the props – it shouldn’t glide open without any resistance.


After verifying prop tightness, glide your fingers along the edges of the props and ensure there aren’t and cracks, chips, or dents in the prop edges. If present, the props must be replaced prior to take-off. It’s important to note that props should be replaced in pairs, along with new prop gaskets.


Continue with a comprehensive visual inspection. Ensure all components, motors, and ESCs are in impeccable condition with no cracks, or chips. Follow up by checking all the screws, making certain they're tightly fastened and secure.


After securing the components, take a moment to manually spin each motor. This is to detect any resistance or rough movement, which should be non-existent. Encountering difficulty while spinning the motors could point to a potential issue. Should such a resistance or roughness occur, it’s normally caused by coil corrosion, broken bearing or other damages in the motor. Please contact your dealer to have further check.


Spraying System


Preseason is a great time to recalibrate the spraying system. This includes recalibrating all the weight sensors, pumps, and flow meters. On DJI AGRAS App, go into the drone's Spraying System Settings, add a liter of water into the spraying tank, click ‘Clear Trapped Air’ first to clear trapped air from the sprayer pump hoses, and then do Flow Meter Calibration. Empty the tank, then go into ‘Weight Sensors’ in Spraying System Settings, click ‘Tare Calibration’ to reset the weight display to 0. Then fill your tank with 20 L water, and check whether the payload weight displayed on the upper-right corner is between 16-24L. If so, do Weight Calibration. Lastly, turn on the sprinklers and make sure it can reach its max flow rate, which should be 12 L/min (3.1 gal/min). At the same time, check if there's any leaks.



Batteries and Chargers


Without a doubt, optimal battery performance, including fast charging, can make or break your operation efficiency. Preseason is a great time to ensure your batteries can fast charge. Inspect the charging ports of each battery and make sure there's no corrosion or damage, such as green-tinged rust covering the pin.


This is a good time to mention that any dust, dirt, or debris can be cleaned off from the battery ports and the battery pins of the drone using a 95% alcohol solution and a cotton swab or microfiber towel. This kind of cleaning should be checked and done daily to help extend the life of the battery and of the drone.


Next, test each battery in the drone to verify it can hold a charge and power on the drone. Then check that fast charging still works for each battery and your charger.


And in case you missed it, we have recommended storage protocols for your batteries, which you can find here:



Test Flight


After checking the arms, motors, props, and batteries, you should be ready for test flights that gradually increase the strain on the drone.


  1. Power up your drone and allow it to idle on the ground, and check if there are any errors.
  2. Proceed to a gentle takeoff and hover to let the drone warm up, especially if it hasn't been used for an extended period.
  3. Conduct a manual flight in an open area. Execute 180 or 360-degree spins to assess the drone's response. Listen carefully; motors may appear fine visually, but stress can cause them to emit a whining sound when rotating. Perform these tests without additional weight.
  4. Test the T40's Active Phased Array Radar with a pole or an obstacle in your test field. Be sure to turn on all obstacle avoidance and settings in advance. This is also a good time to check the drone’s altimeter readings by ascending and descending the drone and confirming that the reported altitude of the drone is accurate. This helps verify that the downwards radar is performing properly.
  5. Test the T40's automatic functions. Create a flight route and have the drone complete it.
  6. Fill with the drone's spraying tank and fly it manually. This additional weight and pressure will test the drone's endurance. Run a couple full tanks through the sprinklers to ensure consistent performance.




Spare Parts and Repairs


Before the spraying season begins is a perfect time to stock up on spare parts, tools, and basic repair knowledge and protocols. This preparation can be the difference between a brief delay and a day’s worth of postponed operations. This includes contacting your dealer to confirm recommended aircraft collision protocols so you are prepared should you encounter this scenario.


Parts to Consider


We recommend stocking spares for parts that can be changed quickly in the field and get you airborne in a short time. This includes motors, ESCs, propellers, prop gaskets, and other common quick fixes that are the difference between a 5-10 minute delay vs. a whole day delay. If you have a more serious issue like a crash, a full damage assessment is necessary and a part swap at the field isn't recommended.


Tools and Organization


Having the right tools is as important as having spare parts. Invest in high-quality tools to avoid strip screw heads or other damage. If you're doing repairs in the field, a magnetic containers to keep small parts like screws in place and label sections is helpful to ensure you can locate them when needed. It's also a good idea to have a workbench so you can get the drone off the ground and have an easier time working on it.


Repair Tips and Troubleshooting Strategies


Be systematic in your approach. If a repair becomes necessary, conduct a damage assessment in a well-lit area. If necessary, take pictures throughout the process to help document what you are doing. Each part should be inspected thoroughly. Stay organized; keeping track of what you’re doing is just as critical as the repair itself.


Equip yourself with knowledge. Understanding your T40's flight logs, error codes, and firmware updates can save you time in the field. If you have an error you aren't familiar with, you can look up the error code to help narrow down your next steps.


Authorized Service Centers and Getting Help


Explore DJI Agriculture's Authorized Service Center (ASC) network for support options. To locate the nearest ASC, visit our website at Additionally, ASC details are accessible through the DJI SmartFarm App, where you can directly request repair services for any issue, ranging from crashes to error messages, or even general inquiries. Initiate a service request via the SmartFarm App by selecting your preferred ASC, and provide images and a detailed description of the problem to facilitate quick and efficient resolution.


Please remember, every ASC is ready to support you, irrespective of your purchase location or dealer of your Agras drone.


For direct assistance, reach out to us at This dedicated support email ensures that all our end users globally receive the help they need, with our customer care team committed to responding within 24 hours.


Conclusion and Action Plan


Maintaining your DJI Agras T40 is more than the sum of checking items off a list. It's a discipline that ensures the longevity and efficiency of your investment. Implementing a comprehensive preseason maintenance routine, stocking up on crucial spare parts, and familiarizing yourself with repairs and troubleshooting strategies will give you peace of mind and operational longevity. By adhering to this maintenance guide, you can feel confident in your T40's performance. Now, take the time to conduct these checks, prepare your spares, and know the ins and outs of troubleshooting. Your next spraying season is poised to be the most productive yet.



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