CS ACNS.E.TAWS.015 FLTA function requirements

• ED Decision 2013/031/R found in: GM Remote Aerodrome Air Traffic Services (ED 2019/004/R) Issue 2 (Jul 2020)

CS ACNS.E.TAWS.015 FLTA function requirements ED Decision 2013/031/R (See [AMC1 ACNS.E.TAWS.015](#_DxCrossRefBm573002822)) Provide an FLTA function that: (a) Provides an Forward Looking Terrain Avoidance (FLTA) function that looks ahead of the airplane along and below the airplane’s lateral and vertical flight path and provides suitable alerts if a potential CFIT threat exists. (b) Provides a Required Terrain Clearance (RTC) alerts when the aeroplane is currently above the terrain in the aeroplane’s projected flight path but the projected amount of terrain clearance is considered unsafe for the particular phase of flight. <table align="left" border="1" cellpadding="0" cellspacing="0" width="603"><tr><td valign="top" width="340"><p>TAWS REQUIRED TERRAIN CLEARANCE (RTC) BY PHASE OF FLIGHT</p></td><td valign="top" width="146"><p>TAWS (RTC)</p><p>Level Flight</p></td><td valign="top" width="117"><p>TAWS (RTC)</p><p>Descending /climbing</p></td></tr><tr><td valign="top" width="340"><p>En route </p></td><td valign="top" width="146"><p>215m (700 ft)</p></td><td valign="top" width="117"><p>150 m (500 ft)</p></td></tr><tr><td valign="top" width="340"><p>Terminal (Intermediate Segment) </p></td><td valign="top" width="146"><p>105 m (350 ft)</p></td><td valign="top" width="117"><p>90 m (300 ft)</p></td></tr><tr><td valign="top" width="340"><p>Approach </p></td><td valign="top" width="146"><p>45 m (150 ft)</p></td><td valign="top" width="117"><p>30 m (100 ft)</p></td></tr><tr><td valign="top" width="340"><p>Departure (above 400 ft) </p></td><td valign="top" width="146"><p>30 m (100 ft)</p></td><td valign="top" width="117"><p>30 m (100 ft)</p></td></tr></table> TABLE 1 (c) gives Imminent Terrain Impact alerts when the aeroplane is currently below the elevation of a terrain cell along the aeroplane’s lateral projected flight path and, based upon the vertical projected flight path, the equipment predicts that the terrain clearance will be less than the value given in the RTC column of Table 1. (d) gives alerts for the Imminent Terrain Impact and Required Terrain Clearance functions when the aeroplane is in turning flight.