From 08ef16e1a90a42461fc02f07434093139676fadb Mon Sep 17 00:00:00 2001
From: Klaus Basan <klaus.basan@klausbasan.de>
Date: Wed, 26 Feb 2020 00:42:52 +0100
Subject: [PATCH] Ref T773, check for "nan" for elevations

---
 src/plugins/simulator/xplane/simulatorxplane.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/plugins/simulator/xplane/simulatorxplane.cpp b/src/plugins/simulator/xplane/simulatorxplane.cpp
index 639ed5cb9..3ddad2e26 100644
--- a/src/plugins/simulator/xplane/simulatorxplane.cpp
+++ b/src/plugins/simulator/xplane/simulatorxplane.cpp
@@ -1061,7 +1061,7 @@ namespace BlackSimPlugin
                 if (!xpAircraft.hasCallsign()) { continue; }
 
                 const double cgValue = verticalOffsetsMeters[i]; // XP offset is swift CG
-                const CAltitude elevationAlt(elevationsMeters[i], CLengthUnit::m(), CLengthUnit::ft());
+                const CAltitude elevationAlt = std::isnan(elevationsMeters[i]) ? CAltitude::null() : CAltitude(elevationsMeters[i], CLengthUnit::m(), CLengthUnit::ft());
                 const CElevationPlane elevation(CLatitude(latitudesDeg[i], CAngleUnit::deg()), CLongitude(longitudesDeg[i], CAngleUnit::deg()), elevationAlt, CElevationPlane::singlePointRadius());
                 const CLength cg = std::isnan(cgValue) ?
                                    CLength::null() :