diff --git a/src/blackcore/simulator.h b/src/blackcore/simulator.h
index 0efdcacef..1ae427088 100644
--- a/src/blackcore/simulator.h
+++ b/src/blackcore/simulator.h
@@ -164,6 +164,7 @@ namespace BlackCore
         virtual bool isShuttingDown() const = 0;
 
         //! Set interpolation mode, empty callsign applies to all know callsigns
+        //! \return Returns true if the mode changed, otherwise false. Note that some implementations always return true.
         virtual bool setInterpolatorMode(BlackMisc::Simulation::CInterpolatorMulti::Mode mode, const BlackMisc::Aviation::CCallsign &callsign) = 0;
 
         //! \addtogroup swiftdotcommands
diff --git a/src/plugins/simulator/fs9/fs9client.h b/src/plugins/simulator/fs9/fs9client.h
index 569dd9745..7389acaf6 100644
--- a/src/plugins/simulator/fs9/fs9client.h
+++ b/src/plugins/simulator/fs9/fs9client.h
@@ -11,7 +11,7 @@
 #define DIRECTPLAY_CLIENT_H
 
 #include "directplaypeer.h"
-#include "blackmisc/simulation/interpolatorlinear.h"
+#include "blackmisc/simulation/interpolatormulti.h"
 #include "blackmisc/aviation/aircraftsituation.h"
 #include "blackmisc/pq/time.h"
 #include "blackmisc/aviation/callsign.h"
@@ -51,7 +51,7 @@ namespace BlackSimPlugin
             void setHostAddress(const QString &hostAddress);
 
             //! Get interpolator
-            BlackMisc::Simulation::CInterpolatorLinear *getInterpolator() { return &m_interpolator; }
+            BlackMisc::Simulation::CInterpolatorMulti *getInterpolator() { return &m_interpolator; }
 
             //! Set interpolation setup
             //! \threadsafe
@@ -94,7 +94,7 @@ namespace BlackSimPlugin
             BlackMisc::Simulation::CInterpolationAndRenderingSetup getInterpolationSetup() const;
 
             BlackMisc::PhysicalQuantities::CTime m_updateInterval;
-            BlackMisc::Simulation::CInterpolatorLinear m_interpolator;
+            BlackMisc::Simulation::CInterpolatorMulti m_interpolator;
             BlackMisc::Simulation::CInterpolationAndRenderingSetup m_interpolationSetup;
             mutable QReadWriteLock m_interpolationSetupMutex;
             QString m_modelName;
diff --git a/src/plugins/simulator/fs9/simulatorfs9.cpp b/src/plugins/simulator/fs9/simulatorfs9.cpp
index ea251cec7..f8bb5585c 100644
--- a/src/plugins/simulator/fs9/simulatorfs9.cpp
+++ b/src/plugins/simulator/fs9/simulatorfs9.cpp
@@ -305,10 +305,12 @@ namespace BlackSimPlugin
 
         bool CSimulatorFs9::setInterpolatorMode(CInterpolatorMulti::Mode mode, const CCallsign &callsign)
         {
-            //! \todo (added by KWB 3/17) interpolator mode for FS9 needs implementation
-            Q_UNUSED(mode);
-            Q_UNUSED(callsign);
-            return false;
+            const auto it = m_hashFs9Clients.find(callsign);
+            if (it == m_hashFs9Clients.end()) { return false; }
+            QTimer::singleShot(0, it->data(), [client = *it, mode] { client->getInterpolator()->setMode(mode); });
+            // Always return true if we were setting the mode, since we cannot easily access the return value from
+            // CInterpolatorMulti::setMode in a thread safe manner.
+            return true;
         }
 
         bool CSimulatorFs9::isPhysicallyRenderedAircraft(const CCallsign &callsign) const