diff --git a/src/comm/MAVLinkSimulationLink.h b/src/comm/MAVLinkSimulationLink.h
index 4c45c518586aef2e62742f76aa6f4a81247d151d..912c5201d4551c679c1dbf6d195b5c3c54cc3426 100644
--- a/src/comm/MAVLinkSimulationLink.h
+++ b/src/comm/MAVLinkSimulationLink.h
@@ -123,7 +123,7 @@ protected:
 
     void enqueue(uint8_t* stream, uint8_t* index, mavlink_message_t* msg);
 
-    static const int8_t systemId = 220;
+    static const uint8_t systemId = 220;
     static const uint8_t componentId = 200;
     static const uint16_t version = 1000;