diff --git a/libraries/AP_Proximity/AP_Proximity.cpp b/libraries/AP_Proximity/AP_Proximity.cpp
index 54799e05bd..91d37466e1 100644
--- a/libraries/AP_Proximity/AP_Proximity.cpp
+++ b/libraries/AP_Proximity/AP_Proximity.cpp
@@ -213,13 +213,6 @@ void AP_Proximity::update()
 
     // check if any face has valid distance when it should not
     boundary.check_face_timeout();
-
-    // work out primary instance - first sensor returning good data
-    for (int8_t i=num_instances-1; i>=0; i--) {
-        if (drivers[i] != nullptr && (state[i].status == Status::Good)) {
-            primary_instance = i;
-        }
-    }
 }
 
 AP_Proximity::Type AP_Proximity::get_type(uint8_t instance) const
@@ -372,7 +365,7 @@ bool AP_Proximity::sensor_present() const
 bool AP_Proximity::sensor_enabled() const
 {
     // check atleast one sensor is enabled
-    return get_type(primary_instance) != Type::None;
+    return (num_instances > 0);
 }
 
 bool AP_Proximity::sensor_failed() const
@@ -395,7 +388,7 @@ bool AP_Proximity::get_upward_distance(float &distance) const
     // get upward distance from backend
     for (uint8_t i=0; i<num_instances; i++) {
         // return first good upward distance
-        if (get_upward_distance(primary_instance, distance)) {
+        if (get_upward_distance(i, distance)) {
             return true;
         }
     }
diff --git a/libraries/AP_Proximity/AP_Proximity.h b/libraries/AP_Proximity/AP_Proximity.h
index e76110da77..54bbb980bb 100644
--- a/libraries/AP_Proximity/AP_Proximity.h
+++ b/libraries/AP_Proximity/AP_Proximity.h
@@ -167,7 +167,6 @@ private:
     static AP_Proximity *_singleton;
     Proximity_State state[PROXIMITY_MAX_INSTANCES];
     AP_Proximity_Backend *drivers[PROXIMITY_MAX_INSTANCES];
-    uint8_t primary_instance;
     uint8_t num_instances;
 
     // return true if the given instance exists