diff --git a/libraries/AP_NavEKF/AP_NavEKF.cpp b/libraries/AP_NavEKF/AP_NavEKF.cpp
index 05652c23a7..5651a8db76 100644
--- a/libraries/AP_NavEKF/AP_NavEKF.cpp
+++ b/libraries/AP_NavEKF/AP_NavEKF.cpp
@@ -455,7 +455,7 @@ bool NavEKF::healthy(void) const
     }
     // barometer and position innovations must be within limits when on-ground
     float horizErrSq = sq(innovVelPos[3]) + sq(innovVelPos[4]);
-    if (!vehicleArmed && (fabsf(innovVelPos[5]) > 1.0f || horizErrSq > 1.0f)) {
+    if (!vehicleArmed && (!hgtHealth || fabsf(hgtInnovFiltState) > 1.0f || horizErrSq > 2.0f)) {
         return false;
     }
 
@@ -2121,17 +2121,26 @@ void NavEKF::FuseVelPosNED()
         if (fuseHgtData) {
             // calculate height innovations
             innovVelPos[5] = statesAtHgtTime.position.z - observation[5];
-
+            // calculate the innovation variance
             varInnovVelPos[5] = P[9][9] + R_OBS_DATA_CHECKS[5];
             // calculate the innovation consistency test ratio
             hgtTestRatio = sq(innovVelPos[5]) / (sq(_hgtInnovGate) * varInnovVelPos[5]);
             // fail if the ratio is > 1, but don't fail if bad IMU data
             hgtHealth = ((hgtTestRatio < 1.0f) || badIMUdata);
-            hgtTimeout = (imuSampleTime_ms - lastHgtPassTime) > hgtRetryTime;
+            hgtTimeout = (imuSampleTime_ms - lastHgtPassTime_ms) > hgtRetryTime;
             // Fuse height data if healthy or timed out or in constant position mode
             if (hgtHealth || hgtTimeout || constPosMode) {
+                // Calculate a filtered value to be used by pre-flight health checks
+                // We need to filter because wind gusts can generate significant baro noise and we want to be able to detect bias errors in the inertial solution
+                if (!vehicleArmed) {
+                    float dtBaro = (imuSampleTime_ms - lastHgtPassTime_ms)*1.0e-3f;
+                    const float hgtInnovFiltTC = 2.0f;
+                    float alpha = constrain_float(dtBaro/(dtBaro+hgtInnovFiltTC),0.0f,1.0f);
+                    hgtInnovFiltState += (innovVelPos[5]-hgtInnovFiltState)*alpha;
+                }
+                // declare height healthy and able to be fused
+                lastHgtPassTime_ms = imuSampleTime_ms;
                 hgtHealth = true;
-                lastHgtPassTime = imuSampleTime_ms;
                 // if timed out, reset the height, but do not fuse data on this time step
                 if (hgtTimeout) {
                     ResetHeight();
@@ -4674,7 +4683,7 @@ void NavEKF::InitialiseVariables()
     lastVelPassTime = imuSampleTime_ms;
     lastPosPassTime = imuSampleTime_ms;
     lastPosFailTime = 0;
-    lastHgtPassTime = imuSampleTime_ms;
+    lastHgtPassTime_ms = imuSampleTime_ms;
     lastTasPassTime = imuSampleTime_ms;
     lastStateStoreTime_ms = imuSampleTime_ms;
     lastFixTime_ms = 0;
@@ -4778,6 +4787,7 @@ void NavEKF::InitialiseVariables()
     imuNoiseFiltState1 = 0.0f;
     imuNoiseFiltState2 = 0.0f;
     lastImuSwitchState = IMUSWITCH_MIXED;
+    hgtInnovFiltState = 0.0f;
 }
 
 // return true if we should use the airspeed sensor
diff --git a/libraries/AP_NavEKF/AP_NavEKF.h b/libraries/AP_NavEKF/AP_NavEKF.h
index 9866aea66f..781dd87b18 100644
--- a/libraries/AP_NavEKF/AP_NavEKF.h
+++ b/libraries/AP_NavEKF/AP_NavEKF.h
@@ -634,7 +634,7 @@ private:
     uint32_t lastVelPassTime;       // time stamp when GPS velocity measurement last passed innovation consistency check (msec)
     uint32_t lastPosPassTime;       // time stamp when GPS position measurement last passed innovation consistency check (msec)
     uint32_t lastPosFailTime;       // time stamp when GPS position measurement last failed innovation consistency check (msec)
-    uint32_t lastHgtPassTime;       // time stamp when height measurement last passed innovation consistency check (msec)
+    uint32_t lastHgtPassTime_ms;    // time stamp when height measurement last passed innovation consistency check (msec)
     uint32_t lastTasPassTime;       // time stamp when airspeed measurement last passed innovation consistency check (msec)
     uint8_t storeIndex;             // State vector storage index
     uint32_t lastStateStoreTime_ms; // time of last state vector storage
@@ -687,6 +687,7 @@ private:
     bool yawResetAngleWaiting;      // true when the yaw reset angle has been updated and has not been retrieved via the getLastYawResetAngle() function
     uint32_t magYawResetTimer_ms;   // timer in msec used to track how long good magnetometer data is failing innovation consistency checks
     bool consistentMagData;         // true when the magnetometers are passing consistency checks
+    float hgtInnovFiltState;        // state used for fitering of the height innovations used for pre-flight checks
 
     // Used by smoothing of state corrections
     Vector10 gpsIncrStateDelta;    // vector of corrections to attitude, velocity and position to be applied over the period between the current and next GPS measurement