Air flow under FMC card can be improved by cut-out
There is little airflow under the FMC mezzanine as most of the bottom
side is blocked by the SFP cage.
As there are no components on the carrier, a large cutout can be made under the FMC to improve the airflow.
See for an example http://www.alpha-data.com/products.php?product=adpe-xrc-5t