Add a generic vertical speed control. Power up the gps.

Aircraft/Generic/generic-autopilot.xml

@@ -445,6 +445,37 @@
     </config>
   </pid-controller>
 
+  <!-- vertical speed hold -->
+  <pid-controller>
+    <name>Vertical Speed Hold</name>
+    <debug>false</debug>
+    <enable>
+      <prop>/autopilot/locks/altitude</prop>
+      <value>vertical-speed-hold</value>
+    </enable>
+    <input>
+      <prop>/velocities/vertical-speed-fps</prop>
+    </input>
+    <reference>
+      <prop>/autopilot/settings/vertical-speed-fpm</prop>
+      <scale>0.01667</scale>
+    </reference>
+    <output>
+      <prop>/controls/flight/elevator-trim</prop>
+    </output>
+    <config>
+      <Kp>-0.01</Kp>      <!-- proportional gain -->
+      <beta>1.0</beta>    <!-- input value weighing factor -->
+      <alpha>0.1</alpha>  <!-- low pass filter weighing factor -->
+      <gamma>0.0</gamma>  <!-- input value weighing factor for -->
+                          <!-- unfiltered derivative error -->
+      <Ti>10.0</Ti>       <!-- integrator time -->
+      <Td>0.00001</Td>    <!-- derivator time -->
+      <u_min>-1.0</u_min> <!-- minimum output clamp -->
+      <u_max>1.0</u_max>  <!-- maximum output clamp -->
+    </config>
+  </pid-controller>
+
 
  <!-- =============================================================== -->
  <!-- Velocity Modes                                                  -->

Aircraft/Generic/generic-electrical.xml

@@ -43,6 +43,7 @@
     <!-- current. -->
     <prop>/systems/electrical/outputs/avionics-fan</prop>
     <prop>/systems/electrical/outputs/gps-mfd</prop>
+    <prop>/systems/electrical/outputs/gps</prop>
     <prop>/systems/electrical/outputs/hsi</prop>
     <prop>/systems/electrical/outputs/navcom[0]</prop>
     <prop>/systems/electrical/outputs/dme</prop>