Fixed server crash.

src/main/java/com/advancedmods/advancedtools/common/items/baubles/RingOfFlight.java

@@ -6,6 +6,7 @@ import com.advancedmods.advancedtools.AdvancedTools;
 import com.advancedmods.advancedtools.common.generic.ATItem;
 import net.minecraft.client.Minecraft;
 import net.minecraft.entity.EntityLivingBase;
+import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.item.ItemStack;
 
 /**
@@ -23,22 +24,29 @@ public class RingOfFlight extends ATItem implements IBauble {
         return BaubleType.RING;
     }
 
+    /*@Override
+    public void onEquippedOrLoadedIntoWorld(ItemStack stack, EntityLivingBase entity) {
+        startFlying((EntityPlayer) entity);
+    }*/
+
     @Override
     public void onWornTick(ItemStack itemStack, EntityLivingBase entityLivingBase) {
-        // NO-OP
+        if(entityLivingBase instanceof EntityPlayer) {
+            EntityPlayer player = ((EntityPlayer) entityLivingBase);
+            if(!player.capabilities.allowFlying) {
+                startFlying(player);
+            }
+        }
     }
 
     @Override
     public void onEquipped(ItemStack itemStack, EntityLivingBase entityLivingBase) {
-        Minecraft mc = Minecraft.getMinecraft();
-        mc.thePlayer.capabilities.allowFlying = true;
+        startFlying((EntityPlayer) entityLivingBase);
     }
 
     @Override
     public void onUnequipped(ItemStack itemStack, EntityLivingBase entityLivingBase) {
-        Minecraft mc = Minecraft.getMinecraft();
-        mc.thePlayer.capabilities.isFlying = false;
-        mc.thePlayer.capabilities.allowFlying = false;
+        stopFlying((EntityPlayer) entityLivingBase);
     }
 
     @Override
@@ -50,4 +58,20 @@ public class RingOfFlight extends ATItem implements IBauble {
     public boolean canUnequip(ItemStack itemStack, EntityLivingBase entityLivingBase) {
         return true;
     }
+
+    private void startFlying(EntityPlayer player) {
+        player.capabilities.allowFlying = true;
+        if(!player.getEntityWorld().isRemote) {
+            player.sendPlayerAbilities();
+        }
+    }
+
+    private void stopFlying(EntityPlayer player) {
+        player.capabilities.allowFlying = false;
+        player.capabilities.isFlying = false;
+
+        if(!player.getEntityWorld().isRemote) {
+            player.sendPlayerAbilities();
+        }
+    }
 }