From 0078a68fbbdcc926d5a9ccc7376393a6488e16fd Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Tue, 15 May 2018 07:21:17 +1000
Subject: [PATCH] SITL: fixed segv when running examples under SITL

---
 libraries/SITL/SIM_Aircraft.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libraries/SITL/SIM_Aircraft.cpp b/libraries/SITL/SIM_Aircraft.cpp
index d9e5a79673..70c7ef54a7 100644
--- a/libraries/SITL/SIM_Aircraft.cpp
+++ b/libraries/SITL/SIM_Aircraft.cpp
@@ -151,7 +151,8 @@ bool Aircraft::parse_home(const char *home_str, Location &loc, float &yaw_degree
 float Aircraft::ground_height_difference() const
 {
     float h1, h2;
-    if (sitl->terrain_enable && terrain &&
+    if (sitl &&
+        sitl->terrain_enable && terrain &&
         terrain->height_amsl(home, h1, false) &&
         terrain->height_amsl(location, h2, false)) {
         return h2 - h1;