From 5e40ad5c38f827f933265e40998dc6f07336e80f Mon Sep 17 00:00:00 2001
From: Randy Mackay <rmackay9@yahoo.com>
Date: Tue, 16 Jun 2015 17:58:22 +0900
Subject: [PATCH] Copter: sonar pre-arm check only if optflow enabled

---
 ArduCopter/motors.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/ArduCopter/motors.cpp b/ArduCopter/motors.cpp
index f87943b62e..1f24e73085 100644
--- a/ArduCopter/motors.cpp
+++ b/ArduCopter/motors.cpp
@@ -513,9 +513,9 @@ bool Copter::pre_arm_checks(bool display_failure)
             return false;
         }
 
-#if CONFIG_SONAR == ENABLED
-        // check range finder
-        if (!sonar.pre_arm_check()) {
+#if CONFIG_SONAR == ENABLED && OPTFLOW == ENABLED
+        // check range finder if optflow enabled
+        if (optflow.enabled() && !sonar.pre_arm_check()) {
             if (display_failure) {
                 gcs_send_text_P(SEVERITY_HIGH,PSTR("PreArm: check range finder"));
             }