diff --git a/ArduCopter/config.h b/ArduCopter/config.h
index 9d3edad354..5f30ff1ac9 100644
--- a/ArduCopter/config.h
+++ b/ArduCopter/config.h
@@ -313,11 +313,6 @@
  #endif
 #endif
 
-// arming check's maximum acceptable vector difference between internal and external compass after vectors are normalized to field length of 1.0
-#ifndef COMPASS_ACCEPTABLE_VECTOR_DIFF
-  #define COMPASS_ACCEPTABLE_VECTOR_DIFF    0.75f    // pre arm compass check will fail if internal vs external compass direction differ by more than 45 degrees
- #endif
-
 //////////////////////////////////////////////////////////////////////////////
 //  OPTICAL_FLOW
 #ifndef OPTFLOW
diff --git a/ArduCopter/motors.cpp b/ArduCopter/motors.cpp
index d2e4f81b09..d4db96d18b 100644
--- a/ArduCopter/motors.cpp
+++ b/ArduCopter/motors.cpp
@@ -373,25 +373,13 @@ bool Copter::pre_arm_checks(bool display_failure)
             return false;
         }
 
-#if COMPASS_MAX_INSTANCES > 1
         // check all compasses point in roughly same direction
-        if (compass.get_count() > 1) {
-            Vector3f prime_mag_vec = compass.get_field_milligauss();
-            prime_mag_vec.normalize();
-            for(uint8_t i=0; i<compass.get_count(); i++) {
-                // get next compass
-                Vector3f mag_vec = compass.get_field_milligauss(i);
-                mag_vec.normalize();
-                Vector3f vec_diff = mag_vec - prime_mag_vec;
-                if (compass.use_for_yaw(i) && vec_diff.length() > COMPASS_ACCEPTABLE_VECTOR_DIFF) {
-                    if (display_failure) {
-                        gcs_send_text_P(MAV_SEVERITY_CRITICAL,PSTR("PreArm: inconsistent compasses"));
-                    }
-                    return false;
-                }
+        if (!compass.consistent()) {
+            if (display_failure) {
+                gcs_send_text_P(MAV_SEVERITY_CRITICAL,PSTR("PreArm: inconsistent compasses"));
             }
+            return false;
         }
-#endif
 
     }