diff --git a/libraries/AP_InertialSensor/AP_InertialSensor.h b/libraries/AP_InertialSensor/AP_InertialSensor.h
index 1ed70e2c9e..389de2fbfa 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor.h
+++ b/libraries/AP_InertialSensor/AP_InertialSensor.h
@@ -94,35 +94,37 @@ public:
     /// @returns	vector of rotational rates in radians/sec
     ///
     const Vector3f     &get_gyro(uint8_t i) const { return _gyro[i]; }
-    const Vector3f     &get_gyro(void) const { return get_gyro(0); }
+    const Vector3f     &get_gyro(void) const { return get_gyro(_get_primary_gyro()); }
     virtual void       set_gyro(const Vector3f &gyro) {}
 
     // set gyro offsets in radians/sec
     const Vector3f &get_gyro_offsets(uint8_t i) const { return _gyro_offset[i]; }
-    const Vector3f &get_gyro_offsets(void) const { return get_gyro_offsets(0); }
+    const Vector3f &get_gyro_offsets(void) const { return get_gyro_offsets(_get_primary_gyro()); }
 
     /// Fetch the current accelerometer values
     ///
     /// @returns	vector of current accelerations in m/s/s
     ///
     const Vector3f     &get_accel(uint8_t i) const { return _accel[i]; }
-    const Vector3f     &get_accel(void) const { return get_accel(0); }
+    const Vector3f     &get_accel(void) const { return get_accel(_get_primary_accel()); }
     virtual void       set_accel(const Vector3f &accel) {}
 
     // multi-device interface
     virtual bool get_gyro_health(uint8_t instance) const;
+    bool get_gyro_health(void) const { return get_gyro_health(_get_primary_gyro()); }
     virtual uint8_t get_gyro_count(void) const { return 1; };
 
     virtual bool get_accel_health(uint8_t instance) const;
+    bool get_accel_health(void) const { return get_accel_health(_get_primary_accel()); }
     virtual uint8_t get_accel_count(void) const { return 1; };
 
     // get accel offsets in m/s/s
     const Vector3f &get_accel_offsets(uint8_t i) const { return _accel_offset[i]; }
-    const Vector3f &get_accel_offsets(void) const { return get_accel_offsets(0); }
+    const Vector3f &get_accel_offsets(void) const { return get_accel_offsets(_get_primary_accel()); }
 
     // get accel scale
     const Vector3f &get_accel_scale(uint8_t i) const { return _accel_scale[i]; }
-    const Vector3f &get_accel_scale(void) const { return get_accel_scale(0); }
+    const Vector3f &get_accel_scale(void) const { return get_accel_scale(_get_primary_accel()); }
 
     /* Update the sensor data, so that getters are nonblocking.
      * Returns a bool of whether data was updated or not.
@@ -157,10 +159,13 @@ public:
     }
 
     virtual uint16_t error_count(void) const { return 0; }
-    virtual bool healthy(void) const { return true; }
+    virtual bool healthy(void) const { return get_gyro_health() && get_accel_health(); }
 
 protected:
 
+    virtual uint8_t _get_primary_gyro(void) const { return 0; }
+    virtual uint8_t _get_primary_accel(void) const { return 0; }
+
     // sensor specific init to be overwritten by descendant classes
     virtual uint16_t        _init_sensor( Sample_rate sample_rate ) = 0;
 
diff --git a/libraries/AP_InertialSensor/AP_InertialSensor_PX4.cpp b/libraries/AP_InertialSensor/AP_InertialSensor_PX4.cpp
index 81014ff1cf..f6dbf92d35 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor_PX4.cpp
+++ b/libraries/AP_InertialSensor/AP_InertialSensor_PX4.cpp
@@ -123,6 +123,7 @@ bool AP_InertialSensor_PX4::get_accel_health(uint8_t k) const
     return true;
     
 }
+
 uint8_t AP_InertialSensor_PX4::get_accel_count(void) const
 {
     return _num_accel_instances;
@@ -232,5 +233,21 @@ bool AP_InertialSensor_PX4::healthy(void) const
     return get_gyro_health(0) && get_accel_health(0);
 }
 
+uint8_t AP_InertialSensor_PX4::_get_primary_gyro(void) const 
+{
+    for (uint8_t i=0; i<INS_MAX_INSTANCES; i++) {
+        if (get_gyro_health(i)) return i;
+    }    
+    return 0;
+}
+
+uint8_t AP_InertialSensor_PX4::_get_primary_accel(void) const 
+{
+    for (uint8_t i=0; i<INS_MAX_INSTANCES; i++) {
+        if (get_accel_health(i)) return i;
+    }    
+    return 0;
+}
+
 #endif // CONFIG_HAL_BOARD
 
diff --git a/libraries/AP_InertialSensor/AP_InertialSensor_PX4.h b/libraries/AP_InertialSensor/AP_InertialSensor_PX4.h
index dbe3dc860a..4ba0c821ac 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor_PX4.h
+++ b/libraries/AP_InertialSensor/AP_InertialSensor_PX4.h
@@ -38,6 +38,9 @@ public:
     uint8_t get_accel_count(void) const;
 
 private:
+    uint8_t _get_primary_gyro(void) const;
+    uint8_t _get_primary_accel(void) const;
+
     uint16_t _init_sensor( Sample_rate sample_rate );
     void     _get_sample(void);
     bool     _sample_available(void);