diff --git a/libraries/AP_Baro/AP_Baro.cpp b/libraries/AP_Baro/AP_Baro.cpp
index 22fa5e055d..1dd8672d55 100644
--- a/libraries/AP_Baro/AP_Baro.cpp
+++ b/libraries/AP_Baro/AP_Baro.cpp
@@ -80,7 +80,15 @@ const AP_Param::GroupInfo AP_Baro::var_info[] = {
 /*
   AP_Baro constructor
  */
-AP_Baro::AP_Baro()
+AP_Baro::AP_Baro() :
+        _num_drivers(0),
+        _num_sensors(0),
+        _primary(0),
+        _last_altitude_EAS2TAS(0.0f),
+        _EAS2TAS(0.0f),
+        _external_temperature(0.0f),
+        _last_external_temperature_ms(0),
+        _hil_mode(false)
 {
     memset(sensors, 0, sizeof(sensors));
 
diff --git a/libraries/AP_Baro/AP_Baro.h b/libraries/AP_Baro/AP_Baro.h
index 61dcf7c507..57eb6e6a4d 100644
--- a/libraries/AP_Baro/AP_Baro.h
+++ b/libraries/AP_Baro/AP_Baro.h
@@ -138,14 +138,14 @@ public:
 
 private:
     // how many drivers do we have?
-    uint8_t _num_drivers = 0;
+    uint8_t _num_drivers;
     AP_Baro_Backend *drivers[BARO_MAX_DRIVERS];
 
     // how many sensors do we have?
-    uint8_t _num_sensors = 0;
+    uint8_t _num_sensors;
 
     // what is the primary sensor at the moment?
-    uint8_t _primary = 0;
+    uint8_t _primary;
 
     struct sensor {
         uint32_t last_update_ms;        // last update time in ms
@@ -160,17 +160,17 @@ private:
     } sensors[BARO_MAX_INSTANCES];
 
     AP_Float                            _alt_offset;
-    float                               _alt_offset_active = 0;
+    float                               _alt_offset_active;
     AP_Int8                             _primary_baro; // primary chosen by user
-    float                               _last_altitude_EAS2TAS = 0;
-    float                               _EAS2TAS = 0;
-    float                               _external_temperature = 0;
-    uint32_t                            _last_external_temperature_ms = 0;
+    float                               _last_altitude_EAS2TAS;
+    float                               _EAS2TAS;
+    float                               _external_temperature;
+    uint32_t                            _last_external_temperature_ms;
     DerivativeFilterFloat_Size7         _climb_rate_filter;
-    bool                                _hil_mode = false;
+    bool                                _hil_mode:1;
 
     // when did we last notify the GCS of new pressure reference?
-    uint32_t                            _last_notify_ms = 0;
+    uint32_t                            _last_notify_ms;
 
     void SimpleAtmosphere(const float alt, float &sigma, float &delta, float &theta);
 };