The APs can do on and off channel scans when they are not servicing clients. This data is used by ARM for calculations.
What information are you looking for?
If you need to "attack" rogues, you'll need dedicated air monitors.
"An AP automatically provides monitoring on its configured channel. For example, an AP servicing clients on channel 1 provides full monitoring on channel 1. If set to perform off-channel scanning, the AP spends brief time intervals scanning other channels in the band. The shorter the scan interval, the less the impact on client performance."
http://www.arubanetworks.com/pdf/technology/tb_air_monitors.pdf