first build

src/main/fc/fc_core.c

@@ -118,6 +118,7 @@ uint8_t motorControlEnable = false;
 static bool isRXDataNew;
 static disarmReason_t lastDisarmReason = DISARM_NONE;
 timeUs_t lastDisarmTimeUs = 0;
+timeMs_t emergInflightRearmTimeout = 0;
 
 static bool prearmWasReset = false; // Prearm must be reset (RC Mode not active) before arming is possible
 static timeMs_t prearmActivationTime = 0;
@@ -176,7 +177,7 @@ int16_t getAxisRcCommand(int16_t rawData, int16_t rate, int16_t deadband)
 {
     int16_t stickDeflection = 0;
 
-#if defined(SITL_BUILD) // Workaround due to strange bug in GCC > 10.2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108914   
+#if defined(SITL_BUILD) // Workaround due to strange bug in GCC > 10.2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108914
     const int16_t value = rawData - PWM_RANGE_MIDDLE;
     if (value < -500) {
         stickDeflection = -500;
@@ -186,9 +187,9 @@ int16_t getAxisRcCommand(int16_t rawData, int16_t rate, int16_t deadband)
         stickDeflection = value;
     }
 #else
-    stickDeflection = constrain(rawData - PWM_RANGE_MIDDLE, -500, 500);   
+    stickDeflection = constrain(rawData - PWM_RANGE_MIDDLE, -500, 500);
 #endif
-    
+
     stickDeflection = applyDeadbandRescaled(stickDeflection, deadband, -500, 500);
     return rcLookup(stickDeflection, rate);
 }
@@ -432,6 +433,7 @@ void disarm(disarmReason_t disarmReason)
     if (ARMING_FLAG(ARMED)) {
         lastDisarmReason = disarmReason;
         lastDisarmTimeUs = micros();
+        emergInflightRearmTimeout = US2MS(lastDisarmTimeUs) + (isProbablyStillFlying() ?  5000 : 0);
         DISABLE_ARMING_FLAG(ARMED);
 
 #ifdef USE_BLACKBOX
@@ -509,6 +511,11 @@ void releaseSharedTelemetryPorts(void) {
     }
 }
 
+bool emergInflightRearmEnabled(void)
+{
+    return millis() < emergInflightRearmTimeout;
+}
+
 void tryArm(void)
 {
     updateArmingStatus();
@@ -529,9 +536,10 @@ void tryArm(void)
 #endif
 
 #ifdef USE_PROGRAMMING_FRAMEWORK
-    if (!isArmingDisabled() || emergencyArmingIsEnabled() || LOGIC_CONDITION_GLOBAL_FLAG(LOGIC_CONDITION_GLOBAL_FLAG_OVERRIDE_ARMING_SAFETY)) {
+    if (!isArmingDisabled() || emergencyArmingIsEnabled() || emergInflightRearmEnabled() ||
+        LOGIC_CONDITION_GLOBAL_FLAG(LOGIC_CONDITION_GLOBAL_FLAG_OVERRIDE_ARMING_SAFETY)) {
 #else
-    if (!isArmingDisabled() || emergencyArmingIsEnabled()) {
+    if (!isArmingDisabled() || emergencyArmingIsEnabled() || emergInflightRearmEnabled()) {
 #endif
         // If nav_extra_arming_safety was bypassed we always
         // allow bypassing it even without the sticks set
@@ -837,7 +845,7 @@ static float calculateThrottleTiltCompensationFactor(uint8_t throttleTiltCompens
 
 void taskMainPidLoop(timeUs_t currentTimeUs)
 {
-  
+
     cycleTime = getTaskDeltaTime(TASK_SELF);
     dT = (float)cycleTime * 0.000001f;
 

src/main/fc/fc_core.h

@@ -43,6 +43,7 @@ void tryArm(void);
 disarmReason_t getDisarmReason(void);
 
 bool emergencyArmingUpdate(bool armingSwitchIsOn);
+bool emergInflightRearmEnabled(void);
 
 bool areSensorsCalibrating(void);
 float getFlightTime(void);

src/main/navigation/navigation.c

@@ -228,6 +228,7 @@ PG_RESET_TEMPLATE(navConfig_t, navConfig,
 static navWapointHeading_t wpHeadingControl;
 navigationPosControl_t posControl;
 navSystemStatus_t NAV_Status;
+static bool landingDetectorIsActive;
 
 EXTENDED_FASTRAM multicopterPosXyCoefficients_t multicopterPosXyCoefficients;
 
@@ -2803,14 +2804,14 @@ void updateLandingStatus(timeMs_t currentTimeMs)
     }
     lastUpdateTimeMs = currentTimeMs;
 
-    static bool landingDetectorIsActive;
-
     DEBUG_SET(DEBUG_LANDING, 0, landingDetectorIsActive);
     DEBUG_SET(DEBUG_LANDING, 1, STATE(LANDING_DETECTED));
 
     if (!ARMING_FLAG(ARMED)) {
-        resetLandingDetector();
+        if (!emergInflightRearmEnabled()) {
-        landingDetectorIsActive = false;
+            resetLandingDetector();
+            landingDetectorIsActive = false;
+        }
         if (!IS_RC_MODE_ACTIVE(BOXARM)) {
             DISABLE_ARMING_FLAG(ARMING_DISABLED_LANDING_DETECTED);
         }
@@ -2852,6 +2853,15 @@ bool isFlightDetected(void)
     return STATE(AIRPLANE) ? isFixedWingFlying() : isMulticopterFlying();
 }
 
+bool isProbablyStillFlying(void)
+{
+    bool inFlightSanityCheck = false;
+    if (STATE(AIRPLANE)) {
+        inFlightSanityCheck = isGPSHeadingValid();
+    }
+    return landingDetectorIsActive && !STATE(LANDING_DETECTED) && inFlightSanityCheck;
+}
+
 /*-----------------------------------------------------------
  * Z-position controller
  *-----------------------------------------------------------*/
@@ -3801,7 +3811,7 @@ static navigationFSMEvent_t selectNavEventFromBoxModeInput(void)
         canActivateWaypoint = false;
 
         // Launch mode can be activated if feature FW_LAUNCH is enabled or BOX is turned on prior to arming (avoid switching to LAUNCH in flight)
-        canActivateLaunchMode = isNavLaunchEnabled();
+        canActivateLaunchMode = isNavLaunchEnabled() && (!sensors(SENSOR_GPS) || (sensors(SENSOR_GPS) && !isGPSHeadingValid()));
     }
 
     return NAV_FSM_EVENT_SWITCH_TO_IDLE;

src/main/navigation/navigation.h

@@ -610,6 +610,7 @@ const char * fixedWingLaunchStateMessage(void);
 float calculateAverageSpeed(void);
 
 void updateLandingStatus(timeMs_t currentTimeMs);
+bool isProbablyStillFlying(void);
 
 const navigationPIDControllers_t* getNavigationPIDControllers(void);
 

src/main/navigation/navigation_fixedwing.c

@@ -692,7 +692,7 @@ bool isFixedWingFlying(void)
     bool velCondition = posControl.actualState.velXY > 250.0f || airspeed > 250.0f;
     bool launchCondition = isNavLaunchEnabled() && fixedWingLaunchStatus() == FW_LAUNCH_FLYING;
 
-    return (isImuHeadingValid() && throttleCondition && velCondition) || launchCondition;
+    return (isGPSHeadingValid() && throttleCondition && velCondition) || launchCondition;
 }
 
 /*-----------------------------------------------------------