190-00692-00 Rev. B Garmin G1000 Pilot’s Guide for Piper PA32 6-45HAZARD AVOIDANCETAWS utilizes terrain and obstacle databases that are referenced to mean sea level (MSL). Using the GPSposition and GPS-MSL altitude, TAWS displays a 2-D picture of the surrounding terrain and obstacles relativeto the position and altitude of the aircraft. Furthermore, the GPS position and GPS-MSL altitude are used tocalculate and “predict” the aircraft’s flight path in relation to the surrounding terrain and obstacles. In thismanner, TAWS can provide advanced alerts of predicted dangerous terrain conditions. Detailed alert modesare described later in this section.BARO-CORRECTED ALTITUDE VERSUS GPS-MSL ALTITUDEBaro-corrected altitude (or indicated altitude) is derived by adjusting the altimeter setting for localatmospheric conditions. The most accurate baro-corrected altitude can be achieved by frequently updatingthe altimeter setting to the nearest reporting station along the flight path. However, because actual atmosphereconditions seldom match the standard conditions defined by the International Standard Atmosphere (ISA)model (where pressure, temperature, and lapse rates have fixed values), it is common for the baro-correctedaltitude (as read from the altimeter) to differ from the GPS-MSL altitude. This variation results in the aircraft’strue altitude differing from the baro-corrected altitude.USING TAWSDuring G1000 power-up, the terrain/obstacle database versions are displayed along with a disclaimer to thepilot. At the same time, TAWS self-test begins. One of the following aural messages is generated:• “TAWS System Test OK”• “TAWS System Failure”TAWS information can be displayed on the following pages:• TAWS Page • AUX - Trip Planning Page• Navigation Map • Flight Plan Pages• PFD Inset MapTAWS can also be displayed on the PFD Inset Map by selecting the INSET Softkey, then the TERRAINSoftkey. TAWS display may also be deselected from the Inset Map without affecting the display on the MFDmaps.To display TAWS data on any page other than the TAWS Page, press the MAP Softkey, then press the TERRAINSoftkey. Terrain and obstacles with heights greater than 200 feet above ground level (AGL) are displayed inyellow and red (Table 6-7). The G1000 adjusts colors automatically as the aircraft altitude changes.
