As with all F-16s since the Block 15, the Block 60 has a programmable data transfer cartridge (DTC). While the physical size of the DTC has not changed over the years, its memory capacity has increased dramatically. In addition to communications and route information, for example, it can also hold a digital terrain elevation database (DTED). The DTED for an operational area is a powerful tool that provides terrain elevation and resultant ground clearance when combined with aircraft altitude.
For low-altitude ingress, the aircraft has two terrain-following (TF) modes. One, database terrain following (DBTF), uses the DTED to assure terrain clearance. The other, radar terrain following (RTF), uses the APG-80 to establish terrain separation. The pilot can select which TF mode he wants to use, and altitudes from 100ft (30m) to 1,000ft can be selected and flown manually or hands off.
Of the two modes, DBTF has several advantages over RTF. First, it is not limited by the radar's physical look-angle capability. Even mildly aggressive manoeuvres at low altitude can move the aircraft's projected flight path outside the radar's field of view. DBTF "sees" all the terrain around the aircraft, allowing for more aggressive manoeuvring during terrain-following ingress to the target.
A reduced radio-frequency signature is another benefit of DBTF operations. Since the radar is not required to assure terrain clearance, the Block 60 is less likely to give away its position by its own radar emissions. But it should not be construed that DBTF will be the pilot's mode of choice. Database terrain following lives in a virtual world, where inaccurate or incomplete terrain data could cause real problems. One large advantage RTF has over DBTF is reality versus virtual reality. RTF uses the actual ground, as sensed by the radar, to compute terrain clearance. In some cases, pilots may be willing to be a bit less stealthy to be more assured of avoiding the ground.