# 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%2FvJUJAeT4srdpBtZiM0Ba%2Fimage.png?alt=media&#x26;token=084b0b59-79e1-4c36-99f0-c41aeceadfc6" 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%2FcowymUdFpIO8bWP6Xzow%2Fimage.png?alt=media&#x26;token=93548fc1-b7b2-4442-b71f-979219cac307" alt=""><figcaption></figcaption></figure>

3.3.3.Tight the batteries.

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