airframesio · thepacket · Apr 22, 2026
diff --git a/lib/MessageDecoder.ts b/lib/MessageDecoder.ts
@@ -78,6 +78,7 @@ const pluginClasses = [
   Plugins.Label_QQ,
   Plugins.Label_QR,
   Plugins.Label_QS,
+  Plugins.Label_A3_PDC,
 ];
 
 export class MessageDecoder {

diff --git a/lib/plugins/Label_A3_PDC.ts b/lib/plugins/Label_A3_PDC.ts
@@ -0,0 +1,325 @@
+import { DecoderPlugin } from '../DecoderPlugin';
+import { DecodeResult, Message, Options } from '../DecoderPluginInterface';
+import { ResultFormatter } from '../utils/result_formatter';
+import { DateTimeUtils } from '../DateTimeUtils';
+
+/**
+ * Label A3 — Pre-Departure Clearance (PDC)
+ *
+ * ATC-issued departure clearance delivered via D-ATIS / datalink, confirming
+ * routing, runway, squawk, frequencies, and ATIS code to the flight crew
+ * before pushback.
+ *
+ * Wire format (single concatenated text with embedded newlines or spaces):
+ *
+ *   RIOCGYA.DC1.CLD 2227 260419 SBGR PDC 692
+ *   IBE0272 CLRD TO LEMD OFF 10L VIA AMVUL6A
+ *   AMVUL6A/NUXEL/F350/NUXEL UZ23 OGSOO DCT EVTOR ...
+ *   ... Z409 TLD
+ *   SQUAWK 4447 ADT 2220 NEXT FREQ 126.900 ATIS Z
+ *   APP 120.454 D02
+ *
+ * Header tokens:
+ *   FACILITY  — originating ATC datalink facility (e.g. RIOCGYA = Rio/Galeão)
+ *   DC<n>     — Departure Clearance message subtype (DC1, DC2, ...)
+ *   CLD       — Clearance message type
+ *   HHMM      — UTC time of clearance
+ *   DDMMYY    — date of clearance
+ *   ICAO      — departure airport
+ *   PDC       — message format keyword
+ *   SEQ       — facility-local PDC sequence number
+ *
+ * Body:
+ *   CALLSIGN CLRD TO <ICAO> OFF <RWY> VIA <SID>
+ *   <route line(s)>
+ *
+ * Trailer (any order):
+ *   SQUAWK <NNNN>
+ *   ADT    <HHMM>           — target/actual departure time (interpreted)
+ *   NEXT FREQ <NNN.NNN>     — next ATC sector frequency
+ *   ATIS   <letter>         — required ATIS information code
+ *   APP <NNN.NNN> D<NN>     — undocumented trailing field, raw only
+ *
+ * Per the analyst's "ignore wild-guesses" guidance, the trailing
+ * `APP ... D02` token is exposed verbatim as a raw string with no
+ * interpretation.
+ */
+export class Label_A3_PDC extends DecoderPlugin {
+  name = 'label-a3-pdc';
+
+  qualifiers() {
+    return {
+      labels: ['A3'],
+    };
+  }
+
+  decode(message: Message, options: Options = {}): DecodeResult {
+    const decodeResult = this.initResult(
+      message,
+      'Pre-Departure Clearance (PDC)',
+    );
+
+    const text = (message.text || '').replace(/\r/g, '').trim();
+    if (!text) {
+      this.setDecodeLevel(decodeResult, false);
+      return decodeResult;
+    }
+
+    // ── Header: FACILITY.DC<n>[./]CLD HHMM YYMMDD ICAO PDC SEQ ──
+    // Separator between SUBTYPE and MSGTYPE is either `.` (e.g. SBGR form)
+    // or `/` (e.g. EDDF/Frankfurt form). A leading `/` in front of the
+    // facility is optional.
+    const headerRe =
+      /\/?(?<facility>[A-Z0-9]+)\.(?<subtype>DC\d+)[./](?<msgtype>[A-Z]{2,4})\s+(?<time>\d{4})\s+(?<date>\d{6})\s+(?<dep>[A-Z]{3,4})\s+(?<format>PDC)\s+(?<seq>\d+)/;
+    const h = text.match(headerRe);
+    if (!h?.groups) {
+      this.setDecodeLevel(decodeResult, false);
+      return decodeResult;
+    }
+
+    const { facility, subtype, msgtype, time, date, dep, format, seq } =
+      h.groups;
+    const headerEnd = (h.index ?? 0) + h[0].length;
+    let body = text.slice(headerEnd).trim();
+
+    // ── Callsign + clearance line: CALLSIGN CLRD TO <ICAO> OFF <RWY> VIA <SID> ──
+    let callsign = '';
+    let destination = '';
+    let runway = '';
+    let sid = '';
+    const clrRe =
+      /(?<callsign>[A-Z]{2,3}\d{1,5}|[A-Z][A-Z0-9]{2,7})\s+CLRD\s+TO\s+(?<dest>[A-Z]{3,4})(?:\s+OFF\s+(?<rwy>\d{1,2}[LRC]?))?(?:\s+VIA\s+(?<sid>[A-Z0-9]+))?/;
+    const c = body.match(clrRe);
+    if (c?.groups) {
+      callsign = c.groups.callsign;
+      destination = c.groups.dest;
+      runway = c.groups.rwy || '';
+      sid = c.groups.sid || '';
+      body = body.slice((c.index ?? 0) + c[0].length).trim();
+    }
+
+    // ── Trailer fields (any order, anywhere in body) ──
+    let squawk = '';
+    let adt = '';
+    let nextFreq = '';
+    let atis = '';
+    let appRaw = '';
+
+    const sqM = body.match(/\bSQUAWK\s+(\d{4})\b/);
+    if (sqM) squawk = sqM[1];
+
+    // ADT is usually HHMM (digits), but some implementations emit a
+    // short alphanumeric flow-control token (e.g. "ADT MDI"). Accept both.
+    const adtM = body.match(/\bADT\s+([A-Z0-9]{2,6})\b/);
+    if (adtM) adt = adtM[1];
+
+    const nfM = body.match(/\bNEXT\s+FREQ\s+(\d{3}\.\d{1,3})\b/);
+    if (nfM) nextFreq = nfM[1];
+
+    const atisM = body.match(/\bATIS\s+([A-Z])\b/);
+    if (atisM) atis = atisM[1];
+
+    const appM = body.match(/\bAPP\s+(\d{3}\.\d{1,3})(?:\s+(D\d{1,3}))?/);
+    if (appM) appRaw = appM[2] ? `${appM[1]} ${appM[2]}` : appM[1];
+
+    // ── Startup / TSAT block (Frankfurt / CFMU-style PDCs) ──
+    //   "STARTUP APPROVED ACCORDING TSAT <token>"
+    //   "STARTUP APPROVED" (no TSAT token)
+    let startup = '';
+    let tsat = '';
+    const startupM = body.match(
+      /\bSTARTUP\s+APPROVED(?:\s+ACCORDING\s+TSAT\s+(?<tsat>[A-Z0-9]+))?/,
+    );
+    if (startupM) {
+      startup = startupM[0].replace(/\s+/g, ' ').trim();
+      tsat = startupM.groups?.tsat || '';
+    }
+
+    // ── Route: everything between SID line and SQUAWK/ADT/NEXT FREQ/ATIS/APP/STARTUP ──
+    const trailerStart = ['SQUAWK', 'ADT', 'NEXT FREQ', 'ATIS ', 'APP ', 'STARTUP']
+      .map((t) => body.indexOf(t))
+      .filter((i) => i >= 0)
+      .reduce((a, b) => Math.min(a, b), body.length);
+    const route = body
+      .slice(0, trailerStart)
+      .replace(/\s+/g, ' ')
+      .trim();
+
+    // ── Date YYMMDD → ISO YYYY-MM-DD (assume 20YY).
+    // Note: the analyst report labels this "DDMMYY" but the wire value
+    // matches YYMMDD against today's date (260419 = 2026-04-19).
+    const yy = date.substring(0, 2);
+    const mo = date.substring(2, 4);
+    const dd = date.substring(4, 6);
+    const isoDate = `20${yy}-${mo}-${dd}`;
+
+    // ── raw[] ──
+    decodeResult.raw.facility = facility;
+    decodeResult.raw.subtype = subtype;
+    decodeResult.raw.message_type = msgtype;
+    decodeResult.raw.format = format;
+    decodeResult.raw.pdc_sequence = seq;
+    decodeResult.raw.date = isoDate;
+    if (callsign) {
+      decodeResult.raw.callsign = callsign;
+      ResultFormatter.flightNumber(decodeResult, callsign);
+    }
+    ResultFormatter.timestamp(
+      decodeResult,
+      DateTimeUtils.convertHHMMSSToTod(time + '00'),
+    );
+    ResultFormatter.departureAirport(decodeResult, dep);
+    if (destination) ResultFormatter.arrivalAirport(decodeResult, destination);
+    if (runway) decodeResult.raw.departure_runway = runway;
+    if (sid) decodeResult.raw.sid = sid;
+    if (route) decodeResult.raw.route = route;
+    if (squawk) decodeResult.raw.squawk = squawk;
+    if (adt) {
+      decodeResult.raw.adt = /^\d{4}$/.test(adt)
+        ? `${adt.substring(0, 2)}:${adt.substring(2, 4)}`
+        : adt;
+    }
+    if (nextFreq) decodeResult.raw.next_frequency = nextFreq;
+    if (atis) decodeResult.raw.atis_code = atis;
+    if (appRaw) decodeResult.raw.app_trailing = appRaw;
+    if (startup) decodeResult.raw.startup_approval = startup;
+    if (tsat) decodeResult.raw.tsat_token = tsat;
+
+    // ── formatted (one row per field) ──
+    decodeResult.formatted.items.unshift(
+      {
+        type: 'message_type',
+        code: 'MSGTYP',
+        label: 'Message Type',
+        value: 'Pre-Departure Clearance (PDC)',
+      },
+      {
+        type: 'facility',
+        code: 'FACILITY',
+        label: 'ATC Facility',
+        value: facility,
+      },
+      {
+        type: 'subtype',
+        code: 'SUBTYPE',
+        label: 'Subtype',
+        value: subtype,
+      },
+    );
+
+    decodeResult.formatted.items.push(
+      {
+        type: 'time',
+        code: 'TIME',
+        label: 'Clearance Time (UTC)',
+        value: `${time.substring(0, 2)}:${time.substring(2, 4)}`,
+      },
+      {
+        type: 'date',
+        code: 'DATE',
+        label: 'Date',
+        value: isoDate,
+      },
+      {
+        type: 'pdc_sequence',
+        code: 'PDCSEQ',
+        label: 'PDC Sequence',
+        value: seq,
+      },
+    );
+    if (callsign) {
+      decodeResult.formatted.items.push({
+        type: 'callsign',
+        code: 'CALLSIGN',
+        label: 'Callsign',
+        value: callsign,
+      });
+    }
+    if (runway) {
+      decodeResult.formatted.items.push({
+        type: 'runway',
+        code: 'RWY',
+        label: 'Departure Runway',
+        value: runway,
+      });
+    }
+    if (sid) {
+      decodeResult.formatted.items.push({
+        type: 'sid',
+        code: 'SID',
+        label: 'SID',
+        value: sid,
+      });
+    }
+    if (route) {
+      decodeResult.formatted.items.push({
+        type: 'route',
+        code: 'ROUTE',
+        label: 'Route',
+        value: route,
+      });
+    }
+    if (squawk) {
+      decodeResult.formatted.items.push({
+        type: 'squawk',
+        code: 'SQK',
+        label: 'Squawk',
+        value: squawk,
+      });
+    }
+    if (adt) {
+      const adtDisplay = /^\d{4}$/.test(adt)
+        ? `${adt.substring(0, 2)}:${adt.substring(2, 4)}`
+        : adt;
+      decodeResult.formatted.items.push({
+        type: 'adt',
+        code: 'ADT',
+        label: 'ADT (UTC / flow token)',
+        value: adtDisplay,
+      });
+    }
+    if (nextFreq) {
+      decodeResult.formatted.items.push({
+        type: 'next_frequency',
+        code: 'NEXTFRQ',
+        label: 'Next Frequency',
+        value: `${nextFreq} MHz`,
+      });
+    }
+    if (atis) {
+      decodeResult.formatted.items.push({
+        type: 'atis_code',
+        code: 'ATIS',
+        label: 'ATIS Code',
+        value: atis,
+      });
+    }
+    if (appRaw) {
+      decodeResult.formatted.items.push({
+        type: 'app_trailing',
+        code: 'APPRAW',
+        label: 'Trailing APP Field (raw)',
+        value: appRaw,
+      });
+    }
+    if (startup) {
+      decodeResult.formatted.items.push({
+        type: 'startup_approval',
+        code: 'STARTUP',
+        label: 'Startup Approval',
+        value: startup,
+      });
+    }
+    if (tsat) {
+      decodeResult.formatted.items.push({
+        type: 'tsat_token',
+        code: 'TSAT',
+        label: 'TSAT / Slot Token',
+        value: tsat,
+      });
+    }
+
+    this.setDecodeLevel(decodeResult, true, 'full');
+    return decodeResult;
+  }
+}
diff --git a/lib/plugins/official.ts b/lib/plugins/official.ts
@@ -64,3 +64,4 @@ export * from './Label_QR';
 export * from './Label_QP';
 export * from './Label_QS';
 export * from './Label_QQ';
+export * from './Label_A3_PDC';