diff --git a/libraries/AP_NavEKF/AP_NavEKF.cpp b/libraries/AP_NavEKF/AP_NavEKF.cpp
index 71e9773371..4807abeb6a 100644
--- a/libraries/AP_NavEKF/AP_NavEKF.cpp
+++ b/libraries/AP_NavEKF/AP_NavEKF.cpp
@@ -3668,16 +3668,17 @@ bool NavEKF::getHAGL(float &HAGL) const
 }
 
 // return data for debugging optical flow fusion
-void NavEKF::getFlowDebug(float &scaleFactor, float &gndPos, float &flowInnovX, float &flowInnovY, float &augFlowInnovX, float &augFlowInnovY, float &rngInnov, float &range) const
+void NavEKF::getFlowDebug(float &scaleFactor, float &estHAGL, float &flowInnovX, float &flowInnovY, float &flowVarX, float &flowVarY, float &rngInnov, float &range, float &gndOffsetErr) const
 {
     scaleFactor = flowStates[0];
-    gndPos = flowStates[1];
+    estHAGL = flowStates[1] - state.position.z;
     flowInnovX = innovOptFlow[0];
     flowInnovY = innovOptFlow[1];
-    augFlowInnovX = auxFlowObsInnov[0];
-    augFlowInnovY = auxFlowObsInnov[1];
+    flowVarX = flowTestRatio[0];
+    flowVarY = flowTestRatio[1];
     rngInnov = innovRng;
     range = rngMea;
+    gndOffsetErr = sqrtf(Popt[1][1]); // note Popt[1][1] is constrained to be non-negative in RunAuxiliaryEKF()
 }
 
 // calculate whether the flight vehicle is on the ground or flying from height, airspeed and GPS speed
diff --git a/libraries/AP_NavEKF/AP_NavEKF.h b/libraries/AP_NavEKF/AP_NavEKF.h
index 25d5779e76..d8f23d0429 100644
--- a/libraries/AP_NavEKF/AP_NavEKF.h
+++ b/libraries/AP_NavEKF/AP_NavEKF.h
@@ -171,7 +171,7 @@ public:
     void  writeOptFlowMeas(uint8_t &rawFlowQuality, Vector2f &rawFlowRates, Vector2f &rawGyroRates, uint32_t &msecFlowMeas, uint8_t &rangeHealth, float &rawSonarRange);
 
     // return data for debugging optical flow fusion
-    void getFlowDebug(float &scaleFactor, float &gndPos, float &flowInnovX, float &flowInnovY, float &augFlowInnovX, float &augFlowInnovY, float &rngInnov, float &range) const;
+    void getFlowDebug(float &scaleFactor, float &gndPos, float &flowInnovX, float &flowInnovY, float &flowVarX, float &flowVarY, float &rngInnov, float &range, float &gndOffsetErr) const;
 
     /*
     return the filter fault status as a bitmasked integer