From cc2a78b70b1f4d6075490f6b48d4084a9f4f4005 Mon Sep 17 00:00:00 2001
From: James Turner <zakalawe@mac.com>
Date: Sat, 10 Jan 2015 19:35:11 +0000
Subject: [PATCH] RNAV: use runway departure end for previous wpt.

Should fix leg computation following a runway waypt.
---
 src/Instrumentation/gps.cxx | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/Instrumentation/gps.cxx b/src/Instrumentation/gps.cxx
index 3b3fa726b..9b808627e 100644
--- a/src/Instrumentation/gps.cxx
+++ b/src/Instrumentation/gps.cxx
@@ -462,13 +462,20 @@ SGGeod GPS::previousLegWaypointPosition(bool& isValid)
 	FlightPlan::Leg* leg = _route->previousLeg();
 	if (leg){
 		Waypt* waypt = leg->waypoint();
-		if(waypt){
-			isValid = true;
+		if (waypt) {
+            isValid = true;
+            // ensure computations use runway end, not threshold
+            if (waypt->type() == "runway") {
+                RunwayWaypt* rwpt = static_cast<RunwayWaypt*>(waypt);
+                return rwpt->runway()->end();
+            }
+
 			return waypt->position();
 		}
 	}
+
 	isValid = false;
-  return SGGeod();
+    return SGGeod();
 }
 ///////////////////////////////////////////////////////////////////////////