diff --git a/app/composables/useSessionState.ts b/app/composables/useSessionState.ts
new file mode 100644
index 0000000..891a266
--- /dev/null
+++ b/app/composables/useSessionState.ts
@@ -0,0 +1,150 @@
+import { computed, ref, watch } from 'vue'
+import { normalizeRadioPhrase, DEFAULT_AIRLINE_TELEPHONY } from '../../shared/utils/radioSpeech'
+import useCommunicationsEngine from '../../shared/utils/communicationsEngine'
+import type { ReadbackFieldDetail } from '~/composables/useRadioBackend'
+
+/**
+ * Reactive state of one /live-atc session: which screen we're on, the backend
+ * session identity, and the "last transmission" strip with its fault-reporting
+ * dialog.
+ *
+ * Split out from useLiveAtcSession (the controller) because almost every other
+ * composable needs some of this — useAtisPlayback wants currentScreen,
+ * usePttRecording wants backendSessionId, useRadioSpeech wants
+ * setLastTransmission — while the controller itself needs those composables to
+ * exist first. State is constructed first, the controller last.
+ */
+export function useSessionState(engine: ReturnType<typeof useCommunicationsEngine>) {
+  const { clearCommunicationLog, sessionId: engineSessionId, flags } = engine
+
+  const currentScreen = ref<'login' | 'flightselect' | 'scenario' | 'monitor' | 'complete'>('login')
+  const loading = ref(false)
+  const error = ref('')
+  const pilotInput = ref('')
+
+  const backendSessionId = ref<string | null>(null)
+  // Last ATC utterance returned by the backend (pre-rendered, correct variables).
+  const lastControllerSay = ref<string | null>(null)
+  // Authoritative expected pilot phrase from the backend — replaces local engine rendering.
+  const backendExpectedPhrase = ref<string | null>(null)
+  // Per-field readback diagnostic from the last transmission (STT debug panel).
+  const lastReadbackReport = ref<ReadbackFieldDetail[]>([])
+  const lastReadbackTranscript = ref<string>('')
+  // Toggle: show radio pronunciation (wun, tree, squawk niner…) vs plain text.
+  const showRadioPronunciation = ref(false)
+
+  function toRadioSpeech(text: string): string {
+    return normalizeRadioPhrase(text, {
+      expandCallsigns: true,
+      expandAirports: true,
+      airlineMap: DEFAULT_AIRLINE_TELEPHONY,
+      sidSuffixIcao: true,
+    })
+  }
+
+  // Display helpers — apply ICAO phonetics when the toggle is on.
+  const displayControllerSay = computed(() =>
+    lastControllerSay.value
+      ? (showRadioPronunciation.value ? toRadioSpeech(lastControllerSay.value) : lastControllerSay.value)
+      : null,
+  )
+  const displayExpectedPhrase = computed(() =>
+    backendExpectedPhrase.value
+      ? (showRadioPronunciation.value ? toRadioSpeech(backendExpectedPhrase.value) : backendExpectedPhrase.value)
+      : null,
+  )
+
+  const lastTransmission = ref('')
+  const lastTransmissionFaulty = ref(false)
+  const lastTransmissionFaultNote = ref('')
+  const showTransmissionIssueDialog = ref(false)
+  const transmissionIssueNote = ref('')
+
+  function setLastTransmission(text: string) {
+    lastTransmission.value = text
+    lastTransmissionFaulty.value = false
+    lastTransmissionFaultNote.value = ''
+  }
+
+  function clearLastTransmission() {
+    setLastTransmission('')
+  }
+
+  function markLastTransmissionFault(note: string) {
+    if (!lastTransmission.value) return
+    lastTransmissionFaulty.value = true
+    lastTransmissionFaultNote.value = note
+  }
+
+  function resetLastTransmissionFault() {
+    lastTransmissionFaulty.value = false
+    lastTransmissionFaultNote.value = ''
+  }
+
+  function startTransmissionIssueFlow() {
+    if (!lastTransmission.value) return
+    transmissionIssueNote.value = lastTransmissionFaultNote.value
+    showTransmissionIssueDialog.value = true
+  }
+
+  function confirmTransmissionIssue() {
+    if (!lastTransmission.value) {
+      showTransmissionIssueDialog.value = false
+      return
+    }
+
+    markLastTransmissionFault(transmissionIssueNote.value.trim())
+    showTransmissionIssueDialog.value = false
+  }
+
+  function removeTransmissionIssue() {
+    resetLastTransmissionFault()
+    showTransmissionIssueDialog.value = false
+  }
+
+  function cancelTransmissionIssue() {
+    showTransmissionIssueDialog.value = false
+  }
+
+  watch(showTransmissionIssueDialog, (open) => {
+    if (!open) {
+      transmissionIssueNote.value = ''
+    }
+  })
+
+  const clearLog = () => {
+    clearCommunicationLog()
+    clearLastTransmission()
+  }
+
+  const sessionLabel = computed(() => engineSessionId.value || flags.value.session_id || '-')
+
+  return {
+    currentScreen,
+    loading,
+    error,
+    pilotInput,
+    backendSessionId,
+    lastControllerSay,
+    backendExpectedPhrase,
+    lastReadbackReport,
+    lastReadbackTranscript,
+    showRadioPronunciation,
+    displayControllerSay,
+    displayExpectedPhrase,
+    lastTransmission,
+    lastTransmissionFaulty,
+    lastTransmissionFaultNote,
+    showTransmissionIssueDialog,
+    transmissionIssueNote,
+    setLastTransmission,
+    clearLastTransmission,
+    resetLastTransmissionFault,
+    startTransmissionIssueFlow,
+    confirmTransmissionIssue,
+    removeTransmissionIssue,
+    cancelTransmissionIssue,
+    clearLog,
+    sessionLabel,
+  }
+}
diff --git a/app/pages/live-atc.vue b/app/pages/live-atc.vue
index 32e089c..f84539c 100644
--- a/app/pages/live-atc.vue
+++ b/app/pages/live-atc.vue
@@ -1515,7 +1515,6 @@
 import { ref, computed, onMounted, onUnmounted, watch, nextTick } from 'vue'
 import { useRouter, useRoute } from 'vue-router'
 import useCommunicationsEngine from "../../shared/utils/communicationsEngine";
-import { normalizeRadioPhrase, DEFAULT_AIRLINE_TELEPHONY } from '../../shared/utils/radioSpeech';
 import { useAuthStore } from '~/stores/auth'
 import { useApi } from '~/composables/useApi'
 import { usePmTheme } from '~/composables/usePmTheme'
@@ -1531,6 +1530,7 @@ import { usePttRecording } from '~/composables/usePttRecording'
 import { useBugReport } from '~/composables/useBugReport'
 import { useDebugSimulation } from '~/composables/useDebugSimulation'
 import { useSimBridgeSync } from '~/composables/useSimBridgeSync'
+import { useSessionState } from '~/composables/useSessionState'
 import { useSpeechInterrupt } from '~/composables/useSpeechInterrupt'
 import { useRadioSpeech } from '~/composables/useRadioSpeech'
 
@@ -1651,96 +1651,34 @@ const {
   expectedPilotPhrases,
 } = engine
 
-const backendSessionId = ref<string | null>(null)
-// Last ATC utterance returned by the backend (pre-rendered, correct variables).
-const lastControllerSay = ref<string | null>(null)
-// Authoritative expected pilot phrase from the backend — replaces local engine rendering.
-const backendExpectedPhrase = ref<string | null>(null)
-// Per-field readback diagnostic from the last transmission (STT debug panel).
-const lastReadbackReport = ref<import('../composables/useRadioBackend').ReadbackFieldDetail[]>([])
-const lastReadbackTranscript = ref<string>('')
-// Toggle: show radio pronunciation (wun, tree, squawk niner…) vs plain text.
-const showRadioPronunciation = ref(false)
-
-function toRadioSpeech(text: string): string {
-  return normalizeRadioPhrase(text, {
-    expandCallsigns: true,
-    expandAirports: true,
-    airlineMap: DEFAULT_AIRLINE_TELEPHONY,
-    sidSuffixIcao: true,
-  })
-}
-
-// Display helpers — apply ICAO phonetics when the toggle is on.
-const displayControllerSay = computed(() =>
-  lastControllerSay.value
-    ? (showRadioPronunciation.value ? toRadioSpeech(lastControllerSay.value) : lastControllerSay.value)
-    : null
-)
-const displayExpectedPhrase = computed(() =>
-  backendExpectedPhrase.value
-    ? (showRadioPronunciation.value ? toRadioSpeech(backendExpectedPhrase.value) : backendExpectedPhrase.value)
-    : null
-)
-
-const lastTransmission = ref('')
-const lastTransmissionFaulty = ref(false)
-const lastTransmissionFaultNote = ref('')
-const showTransmissionIssueDialog = ref(false)
-const transmissionIssueNote = ref('')
-
-function setLastTransmission(text: string) {
-  lastTransmission.value = text
-  lastTransmissionFaulty.value = false
-  lastTransmissionFaultNote.value = ''
-}
-
-function clearLastTransmission() {
-  setLastTransmission('')
-}
-
-function markLastTransmissionFault(note: string) {
-  if (!lastTransmission.value) return
-  lastTransmissionFaulty.value = true
-  lastTransmissionFaultNote.value = note
-}
-
-function resetLastTransmissionFault() {
-  lastTransmissionFaulty.value = false
-  lastTransmissionFaultNote.value = ''
-}
-
-function startTransmissionIssueFlow() {
-  if (!lastTransmission.value) return
-  transmissionIssueNote.value = lastTransmissionFaultNote.value
-  showTransmissionIssueDialog.value = true
-}
-
-function confirmTransmissionIssue() {
-  if (!lastTransmission.value) {
-    showTransmissionIssueDialog.value = false
-    return
-  }
-
-  markLastTransmissionFault(transmissionIssueNote.value.trim())
-  showTransmissionIssueDialog.value = false
-}
-
-function removeTransmissionIssue() {
-  resetLastTransmissionFault()
-  showTransmissionIssueDialog.value = false
-}
-
-function cancelTransmissionIssue() {
-  showTransmissionIssueDialog.value = false
-}
-
-const clearLog = () => {
-  clearCommunicationLog()
-  clearLastTransmission()
-}
-
-const sessionLabel = computed(() => engineSessionId.value || flags.value.session_id || '-')
+const {
+  currentScreen,
+  loading,
+  error,
+  pilotInput,
+  backendSessionId,
+  lastControllerSay,
+  backendExpectedPhrase,
+  lastReadbackReport,
+  lastReadbackTranscript,
+  showRadioPronunciation,
+  displayControllerSay,
+  displayExpectedPhrase,
+  lastTransmission,
+  lastTransmissionFaulty,
+  lastTransmissionFaultNote,
+  showTransmissionIssueDialog,
+  transmissionIssueNote,
+  setLastTransmission,
+  clearLastTransmission,
+  resetLastTransmissionFault,
+  startTransmissionIssueFlow,
+  confirmTransmissionIssue,
+  removeTransmissionIssue,
+  cancelTransmissionIssue,
+  clearLog,
+  sessionLabel,
+} = useSessionState(engine)
 
 // ---------------------------------------------------------------------------
 // Scenario definitions
@@ -1986,10 +1924,6 @@ const oppositeScenario = computed<Scenario | null>(() => {
 })
 
 // UI State
-const currentScreen = ref<'login' | 'flightselect' | 'scenario' | 'monitor' | 'complete'>('login')
-const loading = ref(false)
-const error = ref('')
-const pilotInput = ref('')
 const signalStrength = ref(5)
 const speechSpeed = ref(0.95)
 const radioCheckLoading = ref(false)
@@ -2903,12 +2837,6 @@ onMounted(async () => {
   await requestMicAccess()
 })
 
-watch(showTransmissionIssueDialog, (open) => {
-  if (!open) {
-    transmissionIssueNote.value = ''
-  }
-})
-
 // Watch for frequency changes from engine
 watch(() => activeFrequency.value, (newFreq) => {
   if (newFreq && newFreq !== frequencies.value.active) {