190-00709-04 Rev. A Garmin G1000 Pilot’s Guide for the Socata TBM 850 419HAZARD AVOIDANCE6.7 TAWS-BWARNING: Do not use TAWS information for primary terrain avoidance. TAWS is intended only to enhancesituational awareness.NOTE: Terrain data is not displayed when the aircraft is outside of the terrain database coverage area.NOTE: The data contained in the TAWS databases comes from government agencies. Garmin accuratelyprocesses and cross-validates the data but cannot guarantee the accuracy and completeness of the data.NOTE: Terrain Proximity or Terrain-SVS is disabled when the TAWS-B option is installed.TAWS-B (Terrain Awareness and Warning System - Class B) is an optional feature to increase situational awarenessand aid in reducing controlled flight into terrain (CFIT). TAWS-B provides visual and aural annunciations whenterrain and obstacles are within the given altitude threshold from the aircraft. The displayed alerts and warningsare advisory in nature only.TAWS-B satisfies TSO-C151b Class B requirements for certification.TAWS-B requires the following to operate properly:• A valid terrain/obstacle/airport terrain database• A valid 3-D GPS position solutionTAWS-B uses terrain and obstacle information supplied by government sources. Terrain information is basedon terrain elevation information in a database that may contain inaccuracies. Individual obstructions may beshown if available in the database. The data undergoes verification by Garmin to confirm accuracy of the content,per TSO-C151b. However, the displayed information should never be understood as being all-inclusive and datamay be inaccurate.TAWS-B uses information provided from the GPS receiver to provide a horizontal position and altitude. GPSaltitude is derived from satellite measurements. GPS altitude is then converted to the height above geodetic sealevel (GSL), which is the height above mean sea level (MSL) calculated geometrically. GSL altitude is used todetermine TAWS-B alerts. GSL altitude accuracy is affected by satellite geometry, but is not subject to variationsin pressure and temperature that normally affect pressure altitude sensors. GSL altitude does not require localaltimeter settings to determine MSL altitude. It is a widely-used MSL altitude source. Therefore, GSL altitudeprovides a highly accurate and reliable MSL altitude source to calculate terrain and obstacle alerts.The terrain and obstacle databases used by TAWS-B are referenced to MSL. Using the GPS position and GSLaltitude, TAWS-B displays a 2-D picture of the surrounding terrain and obstacles relative to the position andaltitude of the aircraft. Furthermore, the GPS position and GSL altitude are used to calculate and “predict” theaircraft’s flight path in relation to the surrounding terrain and obstacles. In this manner, TAWS-B can provideadvanced alerts of predicted dangerous terrain conditions.Baro-corrected altitude (or indicated altitude) is derived by adjusting the altimeter setting for local atmosphericconditions. The most accurate baro-corrected altitude can be achieved by frequently updating the altimetersetting to the nearest reporting station along the flight path. However, because actual atmospheric conditions
