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+# Classroom Expansion — Remaining TODOs & Notes
+
+> This file tracks what's left to do, key decisions made, and lessons learned during implementation.
+> See also: `2025-02-15-classroom-expansion-design.md` and `2025-02-15-classroom-expansion-implementation.md`
+
+---
+
+## What's Done
+
+### Track System (Tasks 1-2)
+- [x] `TrackDef` type added to `shared/learn/types.ts`
+- [x] `learnTracks` export in `shared/data/learnModules.ts` wrapping existing modules under "Core Flight Missions"
+- [x] Hub UI renders tracks as vertical sections with track header, subtitle, progress bar
+- [x] `modules` computed derived from `tracks.flatMap()` — backward compatible with search/progress
+
+### Scenario Extensions (Task 3)
+- [x] New fields on `Scenario`: soulsOnBoard, fuelMinutes, positionDescription, holding pattern data, crossing restriction data
+- [x] All generated in `createBaseScenario()` in `shared/learn/scenario.ts`
+
+### VATSIM Essentials Module (Task 4 + Fixes)
+- [x] 6 lessons: Unicom Blind Call, Radio Check, Say Again, Monitor vs Contact, Two-Step Freq Change, ATIS Update
+- [x] **Fixed Radio Check** — removed readability field (pilot can't know it before controller responds), now just practices initiating the radio check call
+- [x] **Fixed Say Again** — expected answer is now concrete ("all before [SID name]") instead of subjective
+- [x] **Fixed Monitor vs Contact** — replaced huge initial-call field with simple "do you transmit? yes/no" field
+
+### Abnormal Comms Module (Task 5)
+- [x] 8 lessons: Conditional Crossing, Complex Holding, Amended Departure, Speed Then Altitude, Immediate Traffic, Multiple Crossing Restrictions, TCAS RA Override, Late Runway Change
+
+---
+
+## What's Left To Do
+
+### Task 6: Emergency Basics Module (7 lessons, type: cloze)
+
+| # | Lesson ID | Title | Key Fields |
+|---|-----------|-------|------------|
+| 1 | `mayday-declaration` | MAYDAY Declaration | station, callsign, nature, intentions, position, heading, fuel minutes, SOB (8 fields) |
+| 2 | `pan-pan-declaration` | PAN PAN Declaration | addressee, callsign, position, nature, assistance, fuel, POB (7 fields) |
+| 3 | `mayday-vs-panpan-fuel` | MAYDAY FUEL vs PAN PAN FUEL | call type decision, fuel state, callsign, request |
+| 4 | `emergency-descent` | Emergency Descent | station, callsign, leaving level, squawk 7700 |
+| 5 | `emergency-query-response` | ATC Emergency Query | fuel in MINUTES (not weight!), souls count (pax + crew) |
+| 6 | `cancel-emergency` | Cancel Emergency | call type, reason, intentions |
+| 7 | `emergency-squawk-codes` | Emergency Squawk Codes | squawk code (7700/7600/7500), associated phraseology |
+
+**Add module to abnormal track:**
+```typescript
+{
+  id: 'emergency-basics',
+  title: 'Emergency · Basics',
+  subtitle: 'MAYDAY, PAN PAN, squawk codes & fuel emergencies',
+  art: gradientArt(['#e65100', '#ef6c00', '#f57c00']),
+  lessons: emergencyBasicsLessons,
+}
+```
+
+**ICAO standards to follow:**
+- MAYDAY spoken 3 times (3 words), PAN PAN spoken 3 times (6 words)
+- Fuel MUST be stated as time remaining, not weight
+- Souls = everyone on board including crew
+- MAYDAY FUEL = calculated usable fuel less than planned final reserve
+- PAN PAN FUEL / MINIMUM FUEL = advisory, fuel above reserve but below planned
+- 7700 = emergency, 7600 = radio failure (NORDO), 7500 = unlawful interference
+- 7500 is NEVER cancelled by radio even if resolved (security protocol)
+
+---
+
+### Task 7: Emergency Scenario Flights (4 multi-step scenarios)
+
+Uses same multi-step engine as Full Flight (`createScenarioSeries()`). Each scenario = 4-5 linked cloze lessons sharing scenario data.
+
+| Scenario | Steps |
+|----------|-------|
+| **Medical Emergency** | Cruise check-in → PAN PAN declaration → ATC priority vectors readback → Approach clearance → Landing + ambulance |
+| **Engine Failure** | MAYDAY declaration → Emergency descent → ATC vectors readback → ILS approach → Landing |
+| **Fuel Emergency (Escalation)** | PAN PAN FUEL → ATC priority readback → MAYDAY FUEL upgrade → Direct vectors → Approach + landing |
+| **Diversion** | Report problem → Request diversion → New clearance readback → Approach at alternate → Landing + taxi |
+
+**Add module to abnormal track:**
+```typescript
+{
+  id: 'emergency-scenarios',
+  title: 'Emergency · Scenario Flights',
+  subtitle: 'Multi-step emergency scenarios from onset to landing',
+  art: gradientArt(['#ff6f00', '#ff8f00', '#ffa000']),
+  lessons: emergencyScenarioLessons,
+}
+```
+
+---
+
+### Tasks 8-10: Decision Mode Engine (NEW exercise type for ATC Perspective)
+
+This is the most complex remaining work — a completely new exercise type.
+
+**New file to create:** `shared/learn/decision-types.ts`
+```typescript
+export type DecisionType = 'sequencing' | 'choice' | 'assignment' | 'priority'
+
+export type FlightStrip = {
+  callsign: string
+  type: string           // aircraft type (A320, B777, C172)
+  altitude: string
+  heading: string
+  position: string
+  intention: string
+  category: 'heavy' | 'medium' | 'light'
+  status: 'emergency' | 'normal'
+}
+
+export type DecisionStep = {
+  prompt: string
+  type: DecisionType
+  options?: string[]          // for choice type
+  items?: string[]            // for sequencing/priority (drag & drop)
+  correct: string | string[]  // correct answer(s)
+  explanation: string         // shown after evaluation
+}
+
+export type DecisionScenario = {
+  briefing: string
+  strips: FlightStrip[]
+  steps: DecisionStep[]
+}
+
+export type DecisionLesson = {
+  id: string
+  title: string
+  desc: string
+  keywords: string[]
+  hints: string[]
+  generate: () => DecisionScenario
+}
+```
+
+**New component:** `app/components/learn/DecisionExercise.vue`
+- Stripboard (left) — flight strip cards
+- Decision area (right) — renders per step type:
+  - `sequencing`: native HTML drag-and-drop list
+  - `choice`: radio button group
+  - `assignment`: dropdown per aircraft
+  - `priority`: drag-and-drop ranking
+- Scoring: Safety 60%, Correctness 30%, Efficiency 10%
+
+**Integration:** `classroom.vue` needs conditional rendering:
+- If `current.meta?.exerciseType === 'decision'` → render `<DecisionExercise>` instead of cloze UI
+- Wire `@complete(score)` to same progress-saving logic
+
+**`ModuleMeta` needs update:**
+```typescript
+export type ModuleMeta = {
+  flightPlan?: boolean
+  briefingArt?: string
+  exerciseType?: 'cloze' | 'decision'
+}
+```
+
+---
+
+### Tasks 11-12: ATC Perspective Lessons (16 decision + 4 reverse sim)
+
+**New file:** `shared/data/learnDecisionModules.ts`
+
+**Module 1: Controller Workflow** (6 lessons)
+1. Departure Sequencing — 3 aircraft, different wake/SIDs → drag into departure order
+2. Arrival Spacing — 4 arrivals → order + assign base headings
+3. Wake Turbulence Separation — Heavy/Medium/Light → pick correct separation times
+4. Runway Conflict — departure, arrival, crosser → pick correct instruction
+5. Frequency Priority — 8 aircraft incl. emergency → rank by priority
+6. Weather Deviation — deviation request + conflicting traffic → approve/deny/alternative
+
+**Module 2: Think Like ATC** (6 lessons)
+1. Departure Puzzle — 2 aircraft same runway, different SIDs/categories → sequence + reasoning
+2. Conflict Detection — 2 converging aircraft → who turns, what heading
+3. Go-Around Call — aircraft on final, runway not clear → go-around or wait + vectors
+4. Emergency Reshuffling — MAYDAY in approach sequence → reprioritize all
+5. Taxi Conflict — 3 aircraft at intersection → hold/continue/reroute
+6. Handoff Timing — climbing aircraft, busy next sector → when to handoff
+
+**Module 3: Reverse Sim** (4 multi-step scenarios)
+1. Busy Ground — 4 aircraft, pushback/taxi/landing conflicts
+2. Tower Rush Hour — 3 departures + 2 arrivals + potential go-around
+3. Approach Sequencing — 5 arrivals from all directions
+4. Emergency Inbound — normal flow disrupted by MAYDAY
+
+**Add as third track:**
+```typescript
+{
+  id: 'atc-perspective',
+  title: 'ATC Perspective Missions',
+  subtitle: 'Understand, decide & control like ATC',
+  modules: [
+    { id: 'controller-workflow', ..., meta: { exerciseType: 'decision' } },
+    { id: 'think-like-atc', ..., meta: { exerciseType: 'decision' } },
+    { id: 'reverse-sim', ..., meta: { exerciseType: 'decision' } },
+  ],
+}
+```
+
+**Adapter needed:** Decision lessons have different shape than Cloze lessons. Either:
+- Extend `ModuleDef` to accept both types
+- Or wrap `DecisionLesson` into a `Lesson`-compatible shell with empty fields
+
+---
+
+### Tasks 13-15: Unlock System + Polish
+
+**Cross-track unlock logic** (update `isModuleUnlocked` in classroom.vue):
+- Core Track: sequential unlock as before
+- Abnormal Track: unlocks after Fundamentals (`normalize`) + Readbacks (`arc`) completed
+- ATC Perspective Track: unlocks after Advanced Calls (`decision-tree`) completed
+- Within each track: sequential unlock
+
+**Lesson search:** Should work automatically since `modules` computed is `tracks.flatMap(t => t.modules)`. Verify by searching "MAYDAY" etc.
+
+**Integration test checklist:**
+- [ ] Hub shows 3 track sections (once all are implemented)
+- [ ] Each Cloze module opens and plays lessons correctly
+- [ ] Multi-step Emergency Scenarios link steps with shared scenario data
+- [ ] Decision Mode renders stripboard + decision area
+- [ ] Scoring saves to server via API
+- [ ] Unlock logic works cross-track
+
+---
+
+## Key Decisions & Lessons Learned
+
+### Design Decisions
+1. **Separate Tracks** (not flat list) — user chose this for clearer organization
+2. **VATSIM Etiquette inside Abnormal track** — not its own track, fits thematically as "what's different on VATSIM"
+3. **ATC Perspective as Interactive Sim** — user chose most ambitious option (not just quiz)
+4. **Emergency exercises: progressive** — basics as cloze drills first, then multi-step scenarios
+
+### Lessons Learned During Implementation
+1. **Radio Check lesson was broken** — showed readability field that pilot can't know before controller responds. Fixed by removing readability, focusing on initiating the check call.
+2. **Say Again was too subjective** — "clearance limit and routing" is just one possible answer. Fixed with concrete expected: "all before [SID name]".
+3. **Monitor vs Contact had too-big initial-call field** — overwhelming for a lesson about one concept. Simplified to yes/no "do you transmit?" field.
+4. **General principle:** Every field must be something the pilot ACTUALLY KNOWS from the ATC phrase. Don't ask for info the pilot has to guess or that comes later in the flow.
+
+### ATC Conformity Sources
+All phraseology verified against:
+- ICAO Doc 9432, Annex 10
+- CAP 413 (UK Radiotelephony Manual)
+- EUROCONTROL Standard Phraseology
+- VATSIM Code of Conduct + operational docs
+- SKYbrary aviation safety references
+
+Key rules enforced:
+- Hold/Hold Short MUST be read back in full (ROGER/WILCO insufficient)
+- Conditional clearances MUST include condition in readback
+- MAYDAY 3x, PAN PAN 3x (6 words)
+- TCAS RA > ATC instruction (pilot MUST refuse)
+- Fuel: MAYDAY FUEL vs PAN PAN FUEL / MINIMUM FUEL
+- Squawk codes: 7700/7600/7500