According to the Russian Interstate Aviation Committee TAWS was turned on. The FAA has developed Class C to make voluntary TAWS usage easier for small aircraft. The aircraft was equipped with TAWS made by Universal Avionics Systems of Tucson. Traditionally the TAWS is a separate unit, however CFS has integrated it into their displays. ADS-B transponder, Inmarsat & VDL datalinks, and a Terrain Avoidance and Warning System (TAWS). The TAWS warning, "Whoop Whoop Pull up!" was heard on the CVR. In the latter case the TAWS was working but the pilot intentionally turned it off. As of 2007, 5% of the world's commercial airlines still lacked a TAWS. Universal offers a Terrain Awareness and Warning System (TAWS) with a 3D perspective mode. In order to overcome this weakness, modern aircraft use a terrain awareness warning system (TAWS).