Keep the screen on in flight, time out silent vision starts, gate Tripod on the ground

From the Mavic Pro simulator run on 2026-10-22:
- The tablet's 2-minute sleep blanked the flight screen mid-flight. The
  flight screen now sets FLAG_KEEP_SCREEN_ON while it is open.
- TapFly's GO got no answer from the aircraft and no error, so the button
  looked dead. ActiveTrack/TapFly starts now give up after 15 s with "the
  aircraft did not answer".
- Tripod works in the air but the flight controller ignores it on the
  ground, so the gate asks to take off first.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Fly App/android/app/src/main/kotlin/com/pilotvault/flyapp/MainActivity.kt

@@ -4,10 +4,12 @@ import android.Manifest
 import android.content.pm.PackageManager
 import android.os.Build
 import android.os.Bundle
+import android.view.WindowManager
 import androidx.core.app.ActivityCompat
 import androidx.core.content.ContextCompat
 import io.flutter.embedding.android.FlutterFragmentActivity
 import io.flutter.embedding.engine.FlutterEngine
+import io.flutter.plugin.common.MethodChannel
 
 // FlutterFragmentActivity (not FlutterActivity) is required by local_auth so the
 // platform BiometricPrompt can attach to a FragmentActivity host.
@@ -21,6 +23,16 @@ class MainActivity : FlutterFragmentActivity() {
         // Live DJI video feed rendered behind the Flight Control HUD.
         flutterEngine.platformViewsController.registry
             .registerViewFactory(DjiVideoView.VIEW_TYPE, DjiVideoViewFactory())
+        // The flight screen keeps the display on (see ScreenAwake in Dart).
+        MethodChannel(flutterEngine.dartExecutor.binaryMessenger, "pilotvault/screen").setMethodCallHandler { call, result ->
+            if (call.method == "keepOn") {
+                if (call.arguments == true) window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
+                else window.clearFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON)
+                result.success(null)
+            } else {
+                result.notImplemented()
+            }
+        }
     }
 
     override fun onCreate(savedInstanceState: Bundle?) {

Fly App/lib/fly/safety_gate.dart

@@ -936,6 +936,8 @@ class SafetyGate {
         if (!model.connected) const GateCheck.block('No aircraft connected.'),
         if (model.connected && on && RailState.activeMode(_a, model.mission) != ActiveMode.none)
           const GateCheck.block('Stop the intelligent flight mode that is running first.'),
+        // A Mavic Pro accepts the write on the ground and keeps Tripod off.
+        if (model.connected && on && !cinematic && _a.isFlying != true) const GateCheck.block('Take off first: Tripod works in flight.'),
         if (model.connected && on)
           GateCheck.warn(cinematic
               ? 'The aircraft brakes and turns slowly: give it room to stop.'

Fly App/lib/fly/screen_awake.dart

@@ -0,0 +1,14 @@
+import 'package:flutter/services.dart';
+
+/// Keeps the tablet's screen on while the flight screen is open: Android's
+/// sleep timeout (2 min on the dev tablet) otherwise blanks the HUD mid-flight.
+abstract final class ScreenAwake {
+  static const MethodChannel _channel = MethodChannel('pilotvault/screen');
+
+  /// Best-effort: a missing host (widget tests) just leaves the screen alone.
+  static Future<void> keepOn(bool on) async {
+    try {
+      await _channel.invokeMethod<void>('keepOn', on);
+    } catch (_) {}
+  }
+}

Fly App/lib/ui/fly/fly_screen.dart

@@ -6,6 +6,7 @@ import 'package:latlong2/latlong.dart' show LatLng;
 
 import '../../dji_service.dart';
 import '../../flight_model.dart';
+import '../../fly/screen_awake.dart';
 import '../../fly/calibration.dart' show CalibrationKind;
 import '../../fly/flight_trail.dart';
 import '../../fly/fly_zone_loader.dart';
@@ -188,6 +189,7 @@ class _FlyScreenState extends State<FlyScreen> {
   @override
   void initState() {
     super.initState();
+    ScreenAwake.keepOn(true);
     SystemChrome.setPreferredOrientations(<DeviceOrientation>[
       DeviceOrientation.landscapeLeft,
       DeviceOrientation.landscapeRight,
@@ -549,6 +551,7 @@ class _FlyScreenState extends State<FlyScreen> {
 
   @override
   void dispose() {
+    ScreenAwake.keepOn(false);
     _m.removeListener(_onModel);
     _m.hudHidden.removeListener(_onHudHidden);
     _m.mission.removeListener(_onMission);

Fly App/lib/ui/fly/modes/vision/vision_panel.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 
 import '../../../../flight_model.dart';
@@ -33,12 +35,19 @@ Future<void> startVisionMode(
     if (r == null) return;
   }
   try {
-    await start();
+    // A start the aircraft never answers (TapFly on a Mavic Pro in the
+    // simulator) would otherwise leave GO looking dead.
+    await start().timeout(startTimeout);
+  } on TimeoutException {
+    onError(title, 'the aircraft did not answer; try again or fly by hand');
   } catch (e) {
     onError(title, e);
   }
 }
 
+/// How long [startVisionMode] waits for the aircraft to accept a start.
+const Duration startTimeout = Duration(seconds: 15);
+
 /// The ActiveTrack / TapFly panel at the head of the left column: what the
 /// operator is doing, the follow style or direction, TapFly's speed, Stop
 /// while it flies, and Exit.

Fly App/test/fly/p7_modes_test.dart

@@ -153,6 +153,13 @@ void main() {
       expect(dji.calls.last, 'setKey(CINEMATIC_MODE_ENABLED, false)');
     });
 
+    test('Tripod waits for take-off; Cinematic does not', () {
+      final SafetyGate g = SafetyGate(model: _model(telemetryTick()..['isFlying'] = false), dji: FakeDjiService());
+      expect(_blockers(g.checkSlowMode(cinematic: false, on: true)), contains(contains('Take off first')));
+      expect(_blockers(g.checkSlowMode(cinematic: true, on: true)), isEmpty);
+      expect(_blockers(g.checkSlowMode(cinematic: false, on: false)), isEmpty, reason: 'turning it off is always allowed');
+    });
+
     test('a Tripod write the aircraft ignores is reported, not silent', () async {
       final _KeepsTripodOff dji = _KeepsTripodOff();
       final SafetyGate g = SafetyGate(model: _model(telemetryTick()), dji: dji);

Fly App/test/fly/vision_modes_test.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:pilotvault_fly/flight_model.dart';
@@ -11,6 +13,7 @@ import 'package:pilotvault_fly/fly/state/mission_state.dart';
 import 'package:pilotvault_fly/fly/telemetry_reducer.dart';
 import 'package:pilotvault_fly/ui/fly/dialogs/slide_to_confirm.dart';
 import 'package:pilotvault_fly/ui/fly/fly_screen.dart';
+import 'package:pilotvault_fly/ui/fly/modes/vision/vision_panel.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
 import 'fake_dji.dart';
@@ -444,4 +447,29 @@ void main() {
       expect(dji.calls.last, 'stopTapFly');
     });
   });
+
+  testWidgets('a vision start the aircraft never answers reports an error', (WidgetTester tester) async {
+    final List<String> errors = <String>[];
+    await tester.pumpWidget(MaterialApp(
+      home: Builder(
+        builder: (BuildContext context) => TextButton(
+          onPressed: () => startVisionMode(
+            context,
+            title: 'TapFly · Forward',
+            icon: 'chevronsRight',
+            description: '',
+            checks: const <GateCheck>[],
+            start: () => Completer<void>().future,
+            onError: (String label, Object e) => errors.add('$label: $e'),
+          ),
+          child: const Text('GO'),
+        ),
+      ),
+    ));
+    await tester.tap(find.text('GO'));
+    await tester.pump(const Duration(seconds: 14));
+    expect(errors, isEmpty);
+    await tester.pump(const Duration(seconds: 2));
+    expect(errors.single, contains('did not answer'));
+  });
 }