diff --git a/src/blackcore/simulator.cpp b/src/blackcore/simulator.cpp
index b5d8aaa86..2ba401aab 100644
--- a/src/blackcore/simulator.cpp
+++ b/src/blackcore/simulator.cpp
@@ -109,7 +109,12 @@ namespace BlackCore
     void ISimulator::rememberElevationAndCG(const CCallsign &callsign, const Geo::CElevationPlane &elevation, const CLength &cg)
     {
         if (callsign.isEmpty()) { return; }
-        if (!elevation.isNull()) { this->rememberGroundElevation(elevation); }
+        if (!elevation.isNull())
+        {
+            const int aircraftCount = this->getAircraftInRangeCount();
+            this->setRememberMaxElevations(aircraftCount * 3); // at least 3 elevations per aircraft, even better as not all are requesting elevations
+            this->rememberGroundElevation(elevation);
+        }
         if (!cg.isNull() && !this->hasSameCG(cg, callsign)) { this->insertCG(cg, callsign); }
     }
 
@@ -120,9 +125,11 @@ namespace BlackCore
         {
             // decouple, follow up of signal can include unloading
             // simulator so this should happen strictly asyncronously (which is like forcing Qt::QueuedConnection)
+            QPointer<ISimulator> myself(this);
             QTimer::singleShot(0, this, [ = ]
             {
-                emit this->simulatorStatusChanged(newStatus);
+                if (!myself) { return; }
+                emit myself->simulatorStatusChanged(newStatus);
             });
         }
     }
diff --git a/src/blackmisc/simulation/simulationenvironmentprovider.cpp b/src/blackmisc/simulation/simulationenvironmentprovider.cpp
index fb8f97b5f..b51338deb 100644
--- a/src/blackmisc/simulation/simulationenvironmentprovider.cpp
+++ b/src/blackmisc/simulation/simulationenvironmentprovider.cpp
@@ -20,6 +20,7 @@ namespace BlackMisc
         bool ISimulationEnvironmentProvider::rememberGroundElevation(const ICoordinateGeodetic &elevationCoordinate, const CLength &epsilon)
         {
             {
+                // no 2nd elevation nearby
                 QReadLocker l(&m_lockElvCoordinates);
                 if (m_elvCoordinates.containsObjectInRange(elevationCoordinate, minRange(epsilon))) { return false; }
             }
@@ -28,7 +29,7 @@ namespace BlackMisc
                 // * we assume we find them faster
                 // * and need the more frequently (the recent ones)
                 QWriteLocker l(&m_lockElvCoordinates);
-                if (m_elvCoordinates.size() > MaxElevations) { m_elvCoordinates.pop_back(); }
+                if (m_elvCoordinates.size() > m_maxElevations) { m_elvCoordinates.pop_back(); }
                 m_elvCoordinates.push_front(elevationCoordinate);
             }
             return true;
@@ -76,9 +77,18 @@ namespace BlackMisc
             return m_elvCoordinates;
         }
 
+        CCoordinateGeodeticList ISimulationEnvironmentProvider::getElevationCoordinates(int &maxRemembered) const
+        {
+            QReadLocker l(&m_lockElvCoordinates);
+            maxRemembered = m_maxElevations;
+            return m_elvCoordinates;
+        }
+
         int ISimulationEnvironmentProvider::cleanUpElevations(const ICoordinateGeodetic &referenceCoordinate, int maxNumber)
         {
-            CCoordinateGeodeticList coordinates(this->getElevationCoordinates());
+            int currentMax;
+            CCoordinateGeodeticList coordinates(this->getElevationCoordinates(currentMax));
+            if (maxNumber < 0) { maxNumber = currentMax; }
             const int size = coordinates.size();
             if (size <= maxNumber) { return 0; }
             coordinates.sortByEuclideanDistanceSquared(referenceCoordinate);
@@ -168,6 +178,19 @@ namespace BlackMisc
             return m_cgs[callsign] == cg;
         }
 
+        int ISimulationEnvironmentProvider::setRememberMaxElevations(int max)
+        {
+            QWriteLocker l(&m_lockElvCoordinates);
+            m_maxElevations = qMax(max, 50);
+            return m_maxElevations;
+        }
+
+        int ISimulationEnvironmentProvider::getRememberMaxElevations() const
+        {
+            QReadLocker l(&m_lockElvCoordinates);
+            return m_maxElevations;
+        }
+
         ISimulationEnvironmentProvider::ISimulationEnvironmentProvider(const CSimulatorPluginInfo &pluginInfo) : m_simulatorPluginInfo(pluginInfo)
         { }
 
diff --git a/src/blackmisc/simulation/simulationenvironmentprovider.h b/src/blackmisc/simulation/simulationenvironmentprovider.h
index 39fb31320..5fcda758c 100644
--- a/src/blackmisc/simulation/simulationenvironmentprovider.h
+++ b/src/blackmisc/simulation/simulationenvironmentprovider.h
@@ -33,7 +33,6 @@ namespace BlackMisc
         {
         public:
             //! All remembered coordiantes
-            //! \remark might be a relatively large list
             //! \threadsafe
             Geo::CCoordinateGeodeticList getElevationCoordinates() const;
 
@@ -77,10 +76,22 @@ namespace BlackMisc
             //! \threadsafe
             bool hasSameCG(const PhysicalQuantities::CLength &cg, const Aviation::CCallsign &callsign) const;
 
+            //! Set number of elevations kept
+            //! \threadsafe
+            int setRememberMaxElevations(int max);
+
+            //! Get number of max. number of elevations
+            //! \threadsafe
+            int getRememberMaxElevations() const;
+
         protected:
             //! Ctor
             ISimulationEnvironmentProvider(const CSimulatorPluginInfo &pluginInfo);
 
+            //! All remembered coordiantes plus max remembered situations
+            //! \threadsafe
+            Geo::CCoordinateGeodeticList getElevationCoordinates(int &maxRemembered) const;
+
             //! New plugin info and default model
             //! \remark normally only used by emulated driver
             //! \threadsafe
@@ -107,7 +118,7 @@ namespace BlackMisc
 
             //! Only keep closest ones
             //! \threadsafe
-            int cleanUpElevations(const Geo::ICoordinateGeodetic &referenceCoordinate, int maxNumber = MaxElevations);
+            int cleanUpElevations(const Geo::ICoordinateGeodetic &referenceCoordinate, int maxNumber = -1);
 
             //! Remember a given elevation
             //! \threadsafe
@@ -129,9 +140,8 @@ namespace BlackMisc
             //! Min.range considered as single point
             static PhysicalQuantities::CLength minRange(const PhysicalQuantities::CLength &range);
 
-            static constexpr int MaxElevations = 1000;  //!< How many elevations we keep
-
         private:
+            int m_maxElevations = 100; //!< How many elevations we keep
             CAircraftModel m_defaultModel; //!< default model
             CSimulatorPluginInfo m_simulatorPluginInfo; //!< info object
             Geo::CCoordinateGeodeticList m_elvCoordinates;