> For the complete documentation index, see [llms.txt](https://bell-505-guide.gitbook.io/bell-505-maintenance-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://bell-505-guide.gitbook.io/bell-505-maintenance-guide/system-descriptions/airframe-systems/environmental-control.md).

# Environmental Control

The environmental control provides ventilation and/or heating to the cabin, indicating/recording system, and defogging for the windshield. It consists of the systems that follow:

* [Distribution](#distribution)
* [Avionics fans](#avionics-fans)
* [Heating](#heating)

## Distribution

The distribution provides ram air ventilation to the cabin. For a system discussion and/or description, refer to [Distribution](/bell-505-maintenance-guide/system-descriptions/airframe-systems/environmental-control/distribution.md).

## Avionics fans

The avionics fans system provides area cooling to the Garmin Display Units (GDU 1040H). It is controlled by the indicating/recording system. For a system discussion and/or description, refer to [Avionics Fans](/bell-505-maintenance-guide/system-descriptions/airframe-systems/environmental-control/avionics-fans.md).

## Heating

The heating provides heated air to the cabin, and defogging for the windshield. For a system discussion and/or description, refer to [Heating](/bell-505-maintenance-guide/system-descriptions/airframe-systems/environmental-control/heating.md).