# Maintenance #### Tether cable Avoid stepping on tether cable. If the tether cable is bent at a sharp angle, the wire can stick out the Kevlar sheath. Make sure to straighten any bent sections before use. {% hint style="info" %} If this wire comes out, you can try to coax it back into the sheath. If this is not possible, please [contact Freefly Support](https://freeflysystems.com/contact) {% endhint %} {% hint style="danger" %} Do not fly or turn on HV with the internal tether wire exposed {% endhint %} #### Tether backup battery Tether ground station has backup battery for keeping tension during a ground station power failure. please ensure the tether ground station is charged more than 50% before flight. {% hint style="info" %} The ground station uses power to reel in the cable, and it cannot be reeled in by hand {% endhint %} #### Light leaf User replaceable with (2) M3x6mm Socket Head Screws. #### Astro Maintenance [Click here for standard Astro maintenance information](https://freefly.gitbook.io/astro-public/maintenance/standard-maintenance-procedures) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.freeflysystems.com/flying-sun/maintenance.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.