started. The older GPWS had no indication of a very close  hazard. However, the system did prevent numerous gear‑up  landings and offered warnings when terrain presented a slope  to much higher terrain. The most basic type (not necessarily certified) of terrain  system is the terrain display. A terrain display uses the  MFD to plot the position of the aircraft against a pictorial  presentation of surrounding terrain. A terrain display usually  relies on a GPS location signal to compare the position and  altitude of the aircraft against the terrain found in an internal  topographical database.  Figure 5-10  shows the position of  the aircraft and surrounding terrain displayed on an MFD. Terrain displays use a simple color‑coding convention to  portray the difference between the present altitude of the  aircraft and the height of the surrounding terrain. Terrain  more than 1,000 feet below the aircraft is coded black. Terrain  less than 1,000 feet but more than 100 feet below the aircraft  is coded yellow. Terrain less than 100 feet below the aircraft  is coded red. Man‑made obstacles (e.g., radio towers, power  lines, buildings) generally do not appear in a topographical  database. Terrain displays are especially useful during departure and  arrival phases of flight. For example, the aircraft shown  in  Figure 5-10 has departed Denver and is heading for a  waypoint situated in high terrain in the Rocky Mountains.  A pilot with good situational awareness has many concerns  during the departure. For instance, is climb performance  meeting expectations? The terrain display reduces the need  for you to perform mental calculations by verifying that  the depiction of the terrain that lies ahead of the aircraft is  steadily changing from red to yellow to black. If the terrain  depiction remains red as the aircraft approaches, you know  there is a problem. Similarly, if the aircraft has been assigned  a heading and altitude vector by air traffic control, the terrain  display provides a simple way of monitoring the safety of  these directives. If the equipment is not certified as meeting  TAWS requirements (see Title 14 of the Code of Federal  Regulations (14 CFR) part 91, section 91.223), the accuracy  can be in doubt. Monitoring Surrounding Terrain During Departure  and Arrival Terrain Display KDEN KFTR KBUC KBJ C KCLN L89 KGHR 308 KLAR KGRN KLVL KHEF KCOS KCEN LAR HCT 31 3000 W GPH 25 100 S S L 1 L R COM2 KFTC H82 MAP NRST WPT AUX 5 338 1 1652 200 46 13.7 2300 23.0 NAV1 117.95 115.40 NAV2  108.00 117.95 123.750 119.925  COM1 135.975 120.050 COM2 GS  123kts  DIS  53.2NM ETE  25:58  ESA  16800 ENGINE MAP DCLTR MAP - NAVIGATION MAP NORTH UP 30NM NAV1 117.95 11 9 9. 92 5 COM1 GS 123kts DIS 53.2 NM  ETE 25:58 ESA Color coding is used to depict the height of surrounding terrain relative to the current altitude of the aircraft.  At its present altitude, this aircraft will not clear the terrain on its way to KRIL. Figure 5-10. Terrain depicted on an MFD. 5-7