diff --git a/src/uas/UAS.cc b/src/uas/UAS.cc
index b372c94f38a8006db9b83ab633446e509b4e009e..ab16e36b7c0e1100bb771909c8905031dc030532 100644
--- a/src/uas/UAS.cc
+++ b/src/uas/UAS.cc
@@ -243,9 +243,11 @@ UAS::UAS(MAVLinkProtocol* protocol, int id) : UASInterface(),
 UAS::~UAS()
 {
     stopHil();
-    // wait for the simulator to exit
-    simulation->wait();
-    simulation->deleteLater();
+    if (simulation) {
+        // wait for the simulator to exit
+        simulation->wait();
+        simulation->deleteLater();
+    }
     writeSettings();
 }