diff --git a/src/blackmisc/simulation/interpolator.cpp b/src/blackmisc/simulation/interpolator.cpp
index 1cea73da1..dbfc34ca4 100644
--- a/src/blackmisc/simulation/interpolator.cpp
+++ b/src/blackmisc/simulation/interpolator.cpp
@@ -63,6 +63,14 @@ namespace BlackMisc
             return cg;
         }
 
+        template<typename Derived>
+        double CInterpolator<Derived>::groundInterpolationFactor()
+        {
+            // done here so we can change value without "larfer" recompilations
+            static constexpr double f = 0.95;
+            return f;
+        }
+
         template<typename Derived>
         void CInterpolator<Derived>::deferredInit()
         {
diff --git a/src/blackmisc/simulation/interpolator.h b/src/blackmisc/simulation/interpolator.h
index d99b18f39..6b333e497 100644
--- a/src/blackmisc/simulation/interpolator.h
+++ b/src/blackmisc/simulation/interpolator.h
@@ -105,6 +105,10 @@ namespace BlackMisc
             //! Center of gravity, fetched from provider in case needed
             PhysicalQuantities::CLength getAndFetchModelCG();
 
+            //! Decides threshold when situation is considered on ground
+            //! \sa BlackMisc::Aviation::CAircraftSituation::setOnGroundFromGroundFactorFromInterpolation
+            static double groundInterpolationFactor();
+
             const Aviation::CCallsign  m_callsign; //!< corresponding callsign
             CAircraftModel m_model; //!< corresponding model
             Aviation::CAircraftSituation m_lastInterpolation { Aviation::CAircraftSituation::null() }; //!< latest interpolation