diff --git a/src/AIModel/AIAircraft.cxx b/src/AIModel/AIAircraft.cxx
index c23ef259c..ed8eda8b7 100644
--- a/src/AIModel/AIAircraft.cxx
+++ b/src/AIModel/AIAircraft.cxx
@@ -446,7 +446,7 @@ void FGAIAircraft::assertSpeed(double speed)
 
 void FGAIAircraft::checkTcas(void)
 {
-    if (tcasThreatNode->getIntValue()==3)
+    if (tcasThreatNode && tcasThreatNode->getIntValue()==3)
     {
         const int RASense = tcasRANode->getIntValue();
         if ((RASense>0)&&(tgt_vs<4000)) {