From 987b556299fae1f9e9f699983d3d188eb50fef0f Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Thu, 6 Sep 2018 08:43:41 +1000
Subject: [PATCH] Plane: disable crash detection if no GPS and no airspeed

---
 ArduPlane/is_flying.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/ArduPlane/is_flying.cpp b/ArduPlane/is_flying.cpp
index 0c2c17dc69..8e7121375d 100644
--- a/ArduPlane/is_flying.cpp
+++ b/ArduPlane/is_flying.cpp
@@ -278,6 +278,12 @@ void Plane::crash_detection_update(void)
         crash_state.checkedHardLanding = false;
     }
 
+    // if we have no GPS lock and we don't have a functional airspeed
+    // sensor then don't do crash detection
+    if (gps.status() < AP_GPS::GPS_OK_FIX_3D && (!airspeed.use() || !airspeed.healthy())) {
+        crashed = false;
+    }
+
     if (!crashed) {
         // reset timer
         crash_state.debounce_timer_ms = 0;