diff --git a/libraries/AP_NavEKF2/AP_NavEKF2_Control.cpp b/libraries/AP_NavEKF2/AP_NavEKF2_Control.cpp
index 12106d6647..fcd9fbfb12 100644
--- a/libraries/AP_NavEKF2/AP_NavEKF2_Control.cpp
+++ b/libraries/AP_NavEKF2/AP_NavEKF2_Control.cpp
@@ -102,8 +102,6 @@ void NavEKF2_core::setAidingMode()
         // We have transitioned either into or out of aiding
         // zero stored velocities used to do dead-reckoning
         heldVelNE.zero();
-        // reset the flag that indicates takeoff for use by optical flow navigation
-        takeOffDetected = false;
         // set various  useage modes based on the condition when we start aiding. These are then held until aiding is stopped.
         if (!isAiding) {
             // We have ceased aiding
diff --git a/libraries/AP_NavEKF2/AP_NavEKF2_VehicleStatus.cpp b/libraries/AP_NavEKF2/AP_NavEKF2_VehicleStatus.cpp
index f6634fd1d5..70db557346 100644
--- a/libraries/AP_NavEKF2/AP_NavEKF2_VehicleStatus.cpp
+++ b/libraries/AP_NavEKF2/AP_NavEKF2_VehicleStatus.cpp
@@ -401,7 +401,8 @@ void NavEKF2_core::setTouchdownExpected(bool val)
 // Detect takeoff for optical flow navigation
 void NavEKF2_core::detectOptFlowTakeoff(void)
 {
-    if (motorsArmed && !takeOffDetected && (imuSampleTime_ms - timeAtArming_ms) > 1000) {
+    if (!onGround && !takeOffDetected && (imuSampleTime_ms - timeAtArming_ms) > 1000) {
+        // we are no longer confidently on the ground so check the range finder and gyro for signs of takeoff
         const AP_InertialSensor &ins = _ahrs->get_ins();
         Vector3f angRateVec;
         Vector3f gyroBias;
@@ -414,6 +415,9 @@ void NavEKF2_core::detectOptFlowTakeoff(void)
         }
 
         takeOffDetected = (takeOffDetected || (angRateVec.length() > 0.1f) || (rngMea > (rngAtStartOfFlight + 0.1f)));
+    } else if (onGround) {
+        // we are confidently on the ground so set the takeoff detected status to false
+        takeOffDetected = false;
     }
 }