<?xml version="1.0"?>

<!-- Alarm on Terrain :

     - excessive rate of descent below 2500 ft.
     - excessive closure rate with ground.
     - gear not locked below 500 ft.

     Cannot move to nasal, because response time must be instantaneous.
-->

<PropertyList>

  <or>
   <and>
    <less-than>
     <property>position/altitude-agl-ft</property>
     <value>2500</value>
    </less-than>
    <less-than>
     <property>/instrumentation/inst-vertical-speed-indicator/indicated-speed-fps</property>
     <value>-50.0</value> <!-- 3000 ft/min (50 s) -->
    </less-than>
   </and>
   <and>
    <less-than>
     <property>position/altitude-agl-ft</property>
     <value>200</value>
    </less-than>
    <less-than>
     <property>/instrumentation/inst-vertical-speed-indicator/indicated-speed-fps</property>
     <value>-15.0</value> <!-- touch down below 900 ft/min -->
    </less-than>
   </and>
   <and>
    <less-than>
     <property>/instrumentation/inst-vertical-speed-indicator/indicated-speed-fps</property>
     <value>-5.0</value> <!-- not null on taxi -->
    </less-than>
    <and>
     <not-equals>
      <property>gear/gear[0]/position-norm</property>
      <value>1.0</value>
      </not-equals>
     <less-than>
      <property>position/altitude-agl-ft</property>
      <value>500</value>
     </less-than>
    </and>
   </and>
  </or>

</PropertyList>
