diff --git a/src/blackmisc/simulation/interpolation/interpolant.h b/src/blackmisc/simulation/interpolation/interpolant.h
index 11f255ed2..1b3661087 100644
--- a/src/blackmisc/simulation/interpolation/interpolant.h
+++ b/src/blackmisc/simulation/interpolation/interpolant.h
@@ -18,10 +18,7 @@ namespace BlackMisc::Simulation
         IInterpolant() = default;
 
         //! Constructor
-        explicit IInterpolant(int situationsAvailable) : m_situationsAvailable(situationsAvailable) {}
-
-        //! Constructor
-        IInterpolant(qint64 interpolatedTime, int situationsAvailable) : m_interpolatedTime(interpolatedTime), m_situationsAvailable(situationsAvailable) {}
+        explicit IInterpolant(qint64 interpolatedTime) : m_interpolatedTime(interpolatedTime) {}
 
         virtual ~IInterpolant() = default;
 
@@ -38,9 +35,6 @@ namespace BlackMisc::Simulation
         //! "Real time" representing the interpolated situation
         qint64 getInterpolatedTime() const { return m_interpolatedTime; }
 
-        //! Situations available
-        int getSituationsAvailable() const { return m_situationsAvailable; }
-
         //! Valid?
         bool isValid() const { return m_valid; }
 
@@ -55,7 +49,6 @@ namespace BlackMisc::Simulation
 
     protected:
         qint64 m_interpolatedTime = -1; //!< "Real time "of interpolated situation
-        int m_situationsAvailable = 0; //!< used situations
         bool m_valid = true; //!< valid?
         bool m_recalculated = false; //!< recalculated interpolant
     };
diff --git a/src/blackmisc/simulation/interpolation/interpolatorlinear.cpp b/src/blackmisc/simulation/interpolation/interpolatorlinear.cpp
index f1f5ff07d..3713d735b 100644
--- a/src/blackmisc/simulation/interpolation/interpolatorlinear.cpp
+++ b/src/blackmisc/simulation/interpolation/interpolatorlinear.cpp
@@ -23,15 +23,13 @@ using namespace BlackMisc::Simulation;
 
 namespace BlackMisc::Simulation
 {
-    CInterpolatorLinear::CInterpolant::CInterpolant(const CAircraftSituation &startSituation) : IInterpolant(1),
-                                                                                                m_startSituation(startSituation), m_pbh(0, startSituation, startSituation)
+    CInterpolatorLinear::CInterpolant::CInterpolant(const CAircraftSituation &startSituation) : m_startSituation(startSituation), m_pbh(0, startSituation, startSituation)
     {}
 
-    CInterpolatorLinear::CInterpolant::CInterpolant(const CAircraftSituation &startSituation, const CInterpolatorLinearPbh &pbh) : IInterpolant(1),
-                                                                                                                             m_startSituation(startSituation), m_pbh(pbh)
+    CInterpolatorLinear::CInterpolant::CInterpolant(const CAircraftSituation &startSituation, const CInterpolatorLinearPbh &pbh) : m_startSituation(startSituation), m_pbh(pbh)
     {}
 
-    CInterpolatorLinear::CInterpolant::CInterpolant(const CAircraftSituation &startSituation, const CAircraftSituation &endSituation, double timeFraction, qint64 interpolatedTime) : IInterpolant(interpolatedTime, 2),
+    CInterpolatorLinear::CInterpolant::CInterpolant(const CAircraftSituation &startSituation, const CAircraftSituation &endSituation, double timeFraction, qint64 interpolatedTime) : IInterpolant(interpolatedTime),
                                                                                                                                                                                       m_startSituation(startSituation), m_endSituation(endSituation),
                                                                                                                                                                                       m_simulationTimeFraction(timeFraction)
     {
diff --git a/src/blackmisc/simulation/interpolation/interpolatorspline.cpp b/src/blackmisc/simulation/interpolation/interpolatorspline.cpp
index 285d7fa70..b8965d215 100644
--- a/src/blackmisc/simulation/interpolation/interpolatorspline.cpp
+++ b/src/blackmisc/simulation/interpolation/interpolatorspline.cpp
@@ -312,7 +312,6 @@ namespace BlackMisc::Simulation
     CInterpolatorSpline::CInterpolant::CInterpolant(const CInterpolatorSpline::PosArray &pa, const CLengthUnit &altitudeUnit, const CInterpolatorLinearPbh &pbh) : m_pa(pa), m_altitudeUnit(altitudeUnit)
     {
         m_pbh = pbh;
-        m_situationsAvailable = pa.size();
     }
 
     std::tuple<Geo::CCoordinateGeodetic, Aviation::CAltitude> CInterpolatorSpline::CInterpolant::interpolatePositionAndAltitude() const