diff --git a/libraries/AP_NavEKF3/AP_NavEKF3.cpp b/libraries/AP_NavEKF3/AP_NavEKF3.cpp
index 13c5d7f859..04090dd760 100644
--- a/libraries/AP_NavEKF3/AP_NavEKF3.cpp
+++ b/libraries/AP_NavEKF3/AP_NavEKF3.cpp
@@ -1422,21 +1422,25 @@ void NavEKF3::getQuaternion(int8_t instance, Quaternion &quat) const
 }
 
 // return the innovations for the specified instance
-void NavEKF3::getInnovations(int8_t instance, Vector3f &velInnov, Vector3f &posInnov, Vector3f &magInnov, float &tasInnov, float &yawInnov) const
+bool NavEKF3::getInnovations(int8_t instance, Vector3f &velInnov, Vector3f &posInnov, Vector3f &magInnov, float &tasInnov, float &yawInnov) const
 {
-    if (instance < 0 || instance >= num_cores) instance = primary;
-    if (core) {
-        core[instance].getInnovations(velInnov, posInnov, magInnov, tasInnov, yawInnov);
+    if (core == nullptr) {
+        return false;
     }
+    if (instance < 0 || instance >= num_cores) instance = primary;
+
+    return core[instance].getInnovations(velInnov, posInnov, magInnov, tasInnov, yawInnov);
 }
 
 // return the innovation consistency test ratios for the velocity, position, magnetometer and true airspeed measurements
-void NavEKF3::getVariances(int8_t instance, float &velVar, float &posVar, float &hgtVar, Vector3f &magVar, float &tasVar, Vector2f &offset) const
+bool NavEKF3::getVariances(int8_t instance, float &velVar, float &posVar, float &hgtVar, Vector3f &magVar, float &tasVar, Vector2f &offset) const
 {
-    if (instance < 0 || instance >= num_cores) instance = primary;
-    if (core) {
-        core[instance].getVariances(velVar, posVar, hgtVar, magVar, tasVar, offset);
+    if (core == nullptr) {
+        return false;
     }
+    if (instance < 0 || instance >= num_cores) instance = primary;
+
+    return core[instance].getVariances(velVar, posVar, hgtVar, magVar, tasVar, offset);
 }
 
 // get a source's velocity innovations for the specified instance.  Set instance to -1 for the primary instance
diff --git a/libraries/AP_NavEKF3/AP_NavEKF3.h b/libraries/AP_NavEKF3/AP_NavEKF3.h
index 3a451f77f8..882a276e00 100644
--- a/libraries/AP_NavEKF3/AP_NavEKF3.h
+++ b/libraries/AP_NavEKF3/AP_NavEKF3.h
@@ -174,11 +174,11 @@ public:
 
     // return the innovations for the specified instance
     // An out of range instance (eg -1) returns data for the primary instance
-    void getInnovations(int8_t index, Vector3f &velInnov, Vector3f &posInnov, Vector3f &magInnov, float &tasInnov, float &yawInnov) const;
+    bool getInnovations(int8_t index, Vector3f &velInnov, Vector3f &posInnov, Vector3f &magInnov, float &tasInnov, float &yawInnov) const;
 
     // return the innovation consistency test ratios for the specified instance
     // An out of range instance (eg -1) returns data for the primary instance
-    void getVariances(int8_t instance, float &velVar, float &posVar, float &hgtVar, Vector3f &magVar, float &tasVar, Vector2f &offset) const;
+    bool getVariances(int8_t instance, float &velVar, float &posVar, float &hgtVar, Vector3f &magVar, float &tasVar, Vector2f &offset) const;
 
     // get a source's velocity innovations for the specified instance.  Set instance to -1 for the primary instance
     // returns true on success and results are placed in innovations and variances arguments
diff --git a/libraries/AP_NavEKF3/AP_NavEKF3_Outputs.cpp b/libraries/AP_NavEKF3/AP_NavEKF3_Outputs.cpp
index 10d8b2a18b..79f4e0bd6f 100644
--- a/libraries/AP_NavEKF3/AP_NavEKF3_Outputs.cpp
+++ b/libraries/AP_NavEKF3/AP_NavEKF3_Outputs.cpp
@@ -405,7 +405,7 @@ uint8_t NavEKF3_core::getActiveAirspeed() const
 }
 
 // return the innovations for the NED Pos, NED Vel, XYZ Mag and Vtas measurements
-void  NavEKF3_core::getInnovations(Vector3f &velInnov, Vector3f &posInnov, Vector3f &magInnov, float &tasInnov, float &yawInnov) const
+bool NavEKF3_core::getInnovations(Vector3f &velInnov, Vector3f &posInnov, Vector3f &magInnov, float &tasInnov, float &yawInnov) const
 {
     velInnov.x = innovVelPos[0];
     velInnov.y = innovVelPos[1];
@@ -418,6 +418,7 @@ void  NavEKF3_core::getInnovations(Vector3f &velInnov, Vector3f &posInnov, Vecto
     magInnov.z = 1e3f*innovMag[2]; // Convert back to sensor units
     tasInnov   = innovVtas;
     yawInnov   = innovYaw;
+    return true;
 }
 
 // return the synthetic air data drag and sideslip innovations
@@ -433,7 +434,7 @@ void NavEKF3_core::getSynthAirDataInnovations(Vector2f &dragInnov, float &betaIn
 // return the innovation consistency test ratios for the velocity, position, magnetometer and true airspeed measurements
 // this indicates the amount of margin available when tuning the various error traps
 // also return the delta in position due to the last position reset
-void  NavEKF3_core::getVariances(float &velVar, float &posVar, float &hgtVar, Vector3f &magVar, float &tasVar, Vector2f &offset) const
+bool NavEKF3_core::getVariances(float &velVar, float &posVar, float &hgtVar, Vector3f &magVar, float &tasVar, Vector2f &offset) const
 {
     velVar   = sqrtF(velTestRatio);
     posVar   = sqrtF(posTestRatio);
@@ -444,6 +445,8 @@ void  NavEKF3_core::getVariances(float &velVar, float &posVar, float &hgtVar, Ve
     magVar.z = sqrtF(MAX(magTestRatio.z,yawTestRatio));
     tasVar   = sqrtF(tasTestRatio);
     offset   = posResetNE.tofloat();
+
+    return true;
 }
 
 // get a particular source's velocity innovations
@@ -550,7 +553,7 @@ void NavEKF3_core::send_status_report(mavlink_channel_t chan) const
     }
 
     // get variances
-    float velVar, posVar, hgtVar, tasVar;
+    float velVar = 0, posVar = 0, hgtVar = 0, tasVar = 0;
     Vector3f magVar;
     Vector2f offset;
     getVariances(velVar, posVar, hgtVar, magVar, tasVar, offset);
diff --git a/libraries/AP_NavEKF3/AP_NavEKF3_core.h b/libraries/AP_NavEKF3/AP_NavEKF3_core.h
index 2ce09595a1..2a89f1a5ab 100644
--- a/libraries/AP_NavEKF3/AP_NavEKF3_core.h
+++ b/libraries/AP_NavEKF3/AP_NavEKF3_core.h
@@ -209,13 +209,13 @@ public:
     void getQuaternion(Quaternion &quat) const;
 
     // return the innovations for the NED Pos, NED Vel, XYZ Mag and Vtas measurements
-    void getInnovations(Vector3f &velInnov, Vector3f &posInnov, Vector3f &magInnov, float &tasInnov, float &yawInnov) const;
+    bool getInnovations(Vector3f &velInnov, Vector3f &posInnov, Vector3f &magInnov, float &tasInnov, float &yawInnov) const;
 
     // return the synthetic air data drag and sideslip innovations
     void getSynthAirDataInnovations(Vector2f &dragInnov, float &betaInnov) const;
 
    // return the innovation consistency test ratios for the velocity, position, magnetometer and true airspeed measurements
-    void getVariances(float &velVar, float &posVar, float &hgtVar, Vector3f &magVar, float &tasVar, Vector2f &offset) const;
+    bool getVariances(float &velVar, float &posVar, float &hgtVar, Vector3f &magVar, float &tasVar, Vector2f &offset) const;
 
     // get a particular source's velocity innovations
     // returns true on success and results are placed in innovations and variances arguments