diff --git a/extplane-plugin/xplaneplugin.cpp b/extplane-plugin/xplaneplugin.cpp
index 6f105e1..c5b722a 100644
--- a/extplane-plugin/xplaneplugin.cpp
+++ b/extplane-plugin/xplaneplugin.cpp
@@ -142,7 +142,7 @@ void XPlanePlugin::updateDataRef(DataRef *ref) {
     {
         IntArrayDataRef *iaRef = qobject_cast<IntArrayDataRef*>(ref);
         int arrayLength = iaRef->value().size();
-        if(arrayLength <= 0) {
+        if(arrayLength == 0) {
             arrayLength = XPLMGetDatavi(iaRef->ref(), nullptr, 0, 0);
             iaRef->setLength(arrayLength);
         }
@@ -210,13 +210,25 @@ void XPlanePlugin::changeDataRef(DataRef *ref)
     case extplaneRefTypeFloatArray:
     {
         FloatArrayDataRef *faRef = qobject_cast<FloatArrayDataRef*>(ref);
-        XPLMSetDatavf(ref->ref(), faRef->valueArray(), 0, faRef->value().size());
+        while(!faRef->changedIndices.empty()) {
+            XPLMSetDatavf(ref->ref(), faRef->valueArray() + faRef->changedIndices.front().first,
+             faRef->changedIndices.front().first,
+             faRef->changedIndices.front().second - faRef->changedIndices.front().first + 1
+            );
+            faRef->changedIndices.pop_front();
+        }
         break;
     }
     case extplaneRefTypeIntArray:
     {
         IntArrayDataRef *iaRef = qobject_cast<IntArrayDataRef*>(ref);
-        XPLMSetDatavi(ref->ref(), iaRef->valueArray(), 0, iaRef->value().size());
+        while(!iaRef->changedIndices.empty()) {
+            XPLMSetDatavi(ref->ref(), iaRef->valueArray() + iaRef->changedIndices.front().first,
+             iaRef->changedIndices.front().first,
+             iaRef->changedIndices.front().second - iaRef->changedIndices.front().first + 1
+            );
+            iaRef->changedIndices.pop_front();
+        }
         break;
     }
     case extplaneRefTypeInt:
diff --git a/extplane-server/datarefs/dataref.h b/extplane-server/datarefs/dataref.h
index eb7509a..869b658 100644
--- a/extplane-server/datarefs/dataref.h
+++ b/extplane-server/datarefs/dataref.h
@@ -18,7 +18,6 @@ enum {
     extplaneRefTypeData = 32
 };
 
-
 /**
   * Base class for DataRefs.
   */
diff --git a/extplane-server/datarefs/floatarraydataref.cpp b/extplane-server/datarefs/floatarraydataref.cpp
index 275bb07..e965724 100644
--- a/extplane-server/datarefs/floatarraydataref.cpp
+++ b/extplane-server/datarefs/floatarraydataref.cpp
@@ -72,6 +72,12 @@ void FloatArrayDataRef::setValue(QString &newValue) {
         float value = values[i].toFloat(&ok);
         if(ok) {
             _valueArray[i] = value;
+            if(changedIndices.empty() || changedIndices.back().second != (i-1))
+            {
+              changedIndices.push_back(std::pair<int, int>(i, i));
+            } else {    
+              changedIndices.back().second = i;
+            }
         } else if(!values.at(i).isEmpty()) {
             INFO << "Invalid value " << values.at(i) << "in array";
         }
diff --git a/extplane-server/datarefs/floatarraydataref.h b/extplane-server/datarefs/floatarraydataref.h
index 0388416..7849fd1 100644
--- a/extplane-server/datarefs/floatarraydataref.h
+++ b/extplane-server/datarefs/floatarraydataref.h
@@ -11,6 +11,7 @@
 
 #include "dataref.h"
 #include <vector>
+#include <list>
 
 class FloatArrayDataRef : public DataRef {
     Q_OBJECT
@@ -19,6 +20,7 @@ class FloatArrayDataRef : public DataRef {
     FloatArrayDataRef(QObject *parent, QString name, void* ref);
     ~FloatArrayDataRef();
     std::vector<float> &value();
+    std::list<std::pair<int, int>> changedIndices;
     virtual void updateValue();
     virtual QString valueString();
     virtual void setValue(QString &newValue);
diff --git a/extplane-server/datarefs/intarraydataref.cpp b/extplane-server/datarefs/intarraydataref.cpp
index 47a92e4..1bcae02 100644
--- a/extplane-server/datarefs/intarraydataref.cpp
+++ b/extplane-server/datarefs/intarraydataref.cpp
@@ -1,7 +1,7 @@
 #include "intarraydataref.h"
 #include "../../util/console.h"
-#include <QStringList>
 #include <algorithm>
+#include <QStringList>
 
 IntArrayDataRef::IntArrayDataRef(QObject *parent, QString name, void *ref) : DataRef(parent, name, ref) {
     _typeString = "ia";
@@ -18,7 +18,9 @@ std::vector<int> & IntArrayDataRef::value() {
     return _values;
 }
 
+// Copies values from valuearray to value list and emits changed as needed
 void IntArrayDataRef::updateValue() {
+    Q_ASSERT(_length > 0);
     bool valuesChanged = false;
     for(int i=0;i<_length;i++){
         if(_values.at(i) != _valueArray[i]) {
@@ -62,23 +64,30 @@ void IntArrayDataRef::setValue(QString &newValue) {
         int value = values[i].toInt(&ok);
         if(ok) {
             _valueArray[i] = value;
+            if(changedIndices.empty() || changedIndices.back().second != (i-1))
+            {
+              changedIndices.push_back(std::pair<int, int>(i, i));
+            } else {    
+              changedIndices.back().second = i;
+            }
         } else if(!values.at(i).isEmpty()) {
             INFO << "Invalid value " << values.at(i) << "in array";
         }
     }
-    emit changed(this);
+    updateValue();
 }
 
 void IntArrayDataRef::setLength(int newLength)
 {
-    Q_ASSERT(newLength > 0);
+    Q_ASSERT(newLength >= 0);
+    _values.resize(newLength);
     std::fill(_values.begin(), _values.end(), -9999);
     if(_valueArray) delete[] _valueArray;
     _valueArray = new int[newLength];
     _length = newLength;
 }
 
-int* IntArrayDataRef::valueArray()
+int *IntArrayDataRef::valueArray()
 {
     Q_ASSERT(_valueArray);
     return _valueArray;
diff --git a/extplane-server/datarefs/intarraydataref.h b/extplane-server/datarefs/intarraydataref.h
index f76b1bb..eb604d7 100644
--- a/extplane-server/datarefs/intarraydataref.h
+++ b/extplane-server/datarefs/intarraydataref.h
@@ -2,8 +2,8 @@
 #define IntArrayDataRef_H
 
 #include "dataref.h"
-#include <QObject>
 #include <vector>
+#include <list>
 
 class IntArrayDataRef : public DataRef {
     Q_OBJECT
@@ -12,6 +12,7 @@ class IntArrayDataRef : public DataRef {
     IntArrayDataRef(QObject *parent, QString name, void* ref);
     ~IntArrayDataRef();
     std::vector<int> &value();
+    std::list<std::pair<int, int>> changedIndices;
     virtual void updateValue();
     virtual QString valueString();
     virtual void setValue(QString &newValue);
diff --git a/protocoldefs.h b/protocoldefs.h
index 2e1448f..c5e0162 100644
--- a/protocoldefs.h
+++ b/protocoldefs.h
@@ -5,7 +5,7 @@
 // Network protocol, currently always 1
 #define EXTPLANE_PROTOCOL 1
 // Feature revision, every time we add a new feature or bug fix, this should be incremented so that clients can know how old the plugin is
-#define EXTPLANE_VERSION 1010
+#define EXTPLANE_VERSION 1011
 
 // Base of udp ports. Bind to this + client_id
 #define UDP_OUT_PORT_BASE 52000