# 3.3. CoG calibration

3.3.1. Put the batteries into the battery compartment.

<figure><img src="https://1851866520-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FIWx9bMxy88NRLPUcOemU%2Fuploads%2Fp8iMnCRHRevWSq1zvcd2%2Fimage.png?alt=media&#x26;token=1b79f304-0887-488e-bf6d-d043f4df3716" alt=""><figcaption></figcaption></figure>

3.3.2. Check the drone center of gravity.

<figure><img src="https://1851866520-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FIWx9bMxy88NRLPUcOemU%2Fuploads%2F523bFKyLCGMs2wvVcmcM%2Fimage.png?alt=media&#x26;token=a1362b84-3941-4de1-8d24-3816cca3d2eb" alt=""><figcaption></figcaption></figure>

3.3.3.Tight the batteries.

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