# 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%2F4tM0pvLf4ttyzM2kAeGw%2Fimage.png?alt=media&#x26;token=3049b1e3-dfe7-47a4-8091-56b2d44785b7" alt=""><figcaption></figcaption></figure>

3.3.2. Check the aircraft center of gravity.

<figure><img src="https://1851866520-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FIWx9bMxy88NRLPUcOemU%2Fuploads%2F14fdrCPZddG2AVlKQCdQ%2Fimage.png?alt=media&#x26;token=716d0580-08fa-4bd7-b140-b60b2c38fc1d" alt=""><figcaption></figcaption></figure>

3.3.3.Tight the batteries.

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