diff --git a/src/blackmisc/aviation/aircraftsituation.cpp b/src/blackmisc/aviation/aircraftsituation.cpp
index 1173bd28e..9f6b9e06e 100644
--- a/src/blackmisc/aviation/aircraftsituation.cpp
+++ b/src/blackmisc/aviation/aircraftsituation.cpp
@@ -617,6 +617,14 @@ namespace BlackMisc
             return altCor;
         }
 
+        CAltitude CAircraftSituation::addAltitudeOffset(const CLength &offset)
+        {
+            if (offset.isNull()) { return this->getAltitude(); }
+            const CAltitude alt = this->getAltitude().withOffset(offset);
+            this->setAltitude(alt);
+            return alt;
+        }
+
         void CAircraftSituation::setPressureAltitude(const CAltitude &altitude)
         {
             Q_ASSERT(altitude.getAltitudeType() == CAltitude::PressureAltitude);
diff --git a/src/blackmisc/aviation/aircraftsituation.h b/src/blackmisc/aviation/aircraftsituation.h
index 7a09e2e48..720513b73 100644
--- a/src/blackmisc/aviation/aircraftsituation.h
+++ b/src/blackmisc/aviation/aircraftsituation.h
@@ -293,6 +293,9 @@ namespace BlackMisc
             //! Set altitude
             void setAltitude(const CAltitude &altitude) { m_position.setGeodeticHeight(altitude); }
 
+            //! Add offset
+            CAltitude addAltitudeOffset(const PhysicalQuantities::CLength &offset);
+
             //! Get pressure altitude
             const CAltitude &getPressureAltitude() const { return m_pressureAltitude; }
 
diff --git a/src/blackmisc/simulation/remoteaircraftprovider.cpp b/src/blackmisc/simulation/remoteaircraftprovider.cpp
index c3d618309..929874e02 100644
--- a/src/blackmisc/simulation/remoteaircraftprovider.cpp
+++ b/src/blackmisc/simulation/remoteaircraftprovider.cpp
@@ -480,10 +480,17 @@ namespace BlackMisc
 
         bool CRemoteAircraftProvider::testAddAltitudeOffsetToSituation(CAircraftSituation &situation) const
         {
-            if (!this->hasTestAltitudeOffset(situation.getCallsign())) { return false; }
-            const CCallsign cs(situation.getCallsign());
+            // for global offset testing set "true"
+            constexpr bool globalOffsetTest = false;
 
+            const CCallsign cs(situation.getCallsign());
+            if (!globalOffsetTest && !this->hasTestAltitudeOffset(cs)) { return false; }
             CLength os;
+            if (globalOffsetTest)
+            {
+                os = CLength(100, CLengthUnit::ft());
+            }
+            else
             {
                 QReadLocker l(&m_lockSituations);
                 os = m_testOffset.value(cs);