diff --git a/libraries/AP_Compass/CompassCalibrator.cpp b/libraries/AP_Compass/CompassCalibrator.cpp
index 2135ab2586..0f7039c3c1 100644
--- a/libraries/AP_Compass/CompassCalibrator.cpp
+++ b/libraries/AP_Compass/CompassCalibrator.cpp
@@ -504,13 +504,10 @@ void CompassCalibrator::run_sphere_fit()
     param_t fit1_params, fit2_params;
     fit1_params = fit2_params = _params;
 
-    float JTJ[COMPASS_CAL_NUM_SPHERE_PARAMS*COMPASS_CAL_NUM_SPHERE_PARAMS];
-    float JTJ2[COMPASS_CAL_NUM_SPHERE_PARAMS*COMPASS_CAL_NUM_SPHERE_PARAMS];
-    float JTFI[COMPASS_CAL_NUM_SPHERE_PARAMS];
+    float JTJ[COMPASS_CAL_NUM_SPHERE_PARAMS*COMPASS_CAL_NUM_SPHERE_PARAMS] = { };
+    float JTJ2[COMPASS_CAL_NUM_SPHERE_PARAMS*COMPASS_CAL_NUM_SPHERE_PARAMS] = { };
+    float JTFI[COMPASS_CAL_NUM_SPHERE_PARAMS] = { };
 
-    memset(JTJ,0,sizeof(JTJ));
-    memset(JTJ2,0,sizeof(JTJ2));
-    memset(JTFI,0,sizeof(JTFI));
     // Gauss Newton Part common for all kind of extensions including LM
     for(uint16_t k = 0; k<_samples_collected; k++) {
         Vector3f sample = _sample_buffer[k].get();
@@ -620,13 +617,10 @@ void CompassCalibrator::run_ellipsoid_fit()
     fit1_params = fit2_params = _params;
 
 
-    float JTJ[COMPASS_CAL_NUM_ELLIPSOID_PARAMS*COMPASS_CAL_NUM_ELLIPSOID_PARAMS];
-    float JTJ2[COMPASS_CAL_NUM_ELLIPSOID_PARAMS*COMPASS_CAL_NUM_ELLIPSOID_PARAMS];
-    float JTFI[COMPASS_CAL_NUM_ELLIPSOID_PARAMS];
+    float JTJ[COMPASS_CAL_NUM_ELLIPSOID_PARAMS*COMPASS_CAL_NUM_ELLIPSOID_PARAMS] = { };
+    float JTJ2[COMPASS_CAL_NUM_ELLIPSOID_PARAMS*COMPASS_CAL_NUM_ELLIPSOID_PARAMS] = { };
+    float JTFI[COMPASS_CAL_NUM_ELLIPSOID_PARAMS] = { };
 
-    memset(JTJ,0,sizeof(JTJ));
-    memset(JTJ2,0,sizeof(JTJ2));
-    memset(JTFI,0,sizeof(JTFI));
     // Gauss Newton Part common for all kind of extensions including LM
     for(uint16_t k = 0; k<_samples_collected; k++) {
         Vector3f sample = _sample_buffer[k].get();