Datalink and Printing

The FM's two outward mouths: datalink (AOC — airline operational communications — plus the ATC applications CPDLC and ADS) and the printer. The ATSU and DCDU themselves belong to ATA-46; this article covers the FM's side of the conversation. (CPDLC/FANS A+ is fitted on the baseline airframe of this series — article 01.)

1. Two systems, one spokesman

The architecture (per AMM 22-76, attributed summary): AOC — airline operational communication, carried by the ACARS management unit or the ATSU, with each FMGEC's AOC activation decided by an OPC option (article 04); and the ATC applications (FANS-A) — CPDLC plus ADS (the FANS A option, ADS additionally needing its ON discrete).

The communications master — the third member of the master family after guidance and A/THR (article 19, article 16): in dual mode only one FMGEC talks to ACARS/ATSU, decided by its own chain — ATSU-to-FM1 bus READY → FM1; else FM2 READY → FM2; neither → no master (independent/single modes: the communications master follows the guidance master). Manual requests count as single-side transmissions with the other side suppressed — with one exception: the ADS frames are broadcast by both FMs. Note the trap: the communications master and the FMA/A-THR master use different decision chains — one watches the ATSU bus, the other watches the AP/FD — and the two "masters" can be different computers.

The AMI master switch: the airline customises 26 function switches through the AMI file (disabling requests, report triggers, auto-printing…) — and a missing AMI file disables all ACARS functions (article 04's "AMI = airline policy", sharpest edge).

2. The AOC uplink brothers — plan, takeoff data, wind

Flight-plan uplink — the review-then-insert flow changes with the clock. Per FCOM DSC-22_20-30-80:

Before engine start, the flight crew may request a route for the active flight plan. When the route is received, 'AOC ACT F-PLN UPLINK' message is displayed on the MCDU indicating that the flight plan has been received and automatically inserted. After engine start, it is not possible to initialize directly the active flight plan since the received flight plan is automatically routed into the secondary, and the MCDU displays 'AOC SEC F-PLN UPLINK'.

Before start: auto-inserted. After start: everything routes into SEC — nothing rewrites the active plan in flight without your INSERT (article 21's fifth official SEC use). Detail: a missing request star means the FM and ACARS aren't talking; and a pending TMPY or DIR TO blocks uplink insertion — finish your own edit first.

Takeoff-data uplink (request two runways, receive up to four runways' V1/VR/V2 in MAX and FLX/DRT pairs — on the ground). Per FCOM DSC-22_20-30-80:

Note: The 'INSERT UPLINK' prompt is not displayed: ‐ If the uplinked runway is different from the active runway. ‐ If the uplinked TOW differs from the FMS-estimated TOW by more than 1 t. ‐ If the uplinked TOCG differs from the FMS-estimated TOCG by more than 0.5 %. ‐ If the uplink is incomplete.

Four gates — wrong runway, weight off by more than a tonne, CG off by more than 0.5 %, or an incomplete package — any one and the INSERT key simply never appears: the system refusing to let another aircraft's numbers into yours (the UPLINK pages themselves are read-only — view, page, insert; never edit). And a side effect worth knowing:

Note: When the flight crew inserts the takeoff data that contains the takeoff runway wind, all of the following occurs: ‐ The wind is automatically inserted as surface wind on the CLIMB WIND page ‐ The FMS no longer considers the TRIP WIND inserted on the INIT FUEL PRED page.

Insert takeoff data carrying the runway wind and TRIP WIND retires on the spot (article 22's second retirement trigger).

Wind uplink — the automated doorway into article 22's four pages. Per FCOM DSC-22_20-30-80:

‐ For the active flight plan or the secondary flight plan that is a 'COPY ACTIVE', a wind request sent by the crew: • During the preflight or takeoff phase, initiates a demand for climb, cruise, descent and alternate winds. • During climb and cruise phase, initiates a demand for cruise, descent and alternate winds. • During descent/approach and go around, no wind request is possible.

The request's contents follow the phase, not the page: preflight/takeoff asks for all four; climb/cruise for the remaining three; descent and beyond — no requests (the winds are locked — article 22's phase locks; a non-COPY-ACTIVE SEC escapes the phase restriction). Before start with empty wind pages, the uplink auto-inserts; otherwise it waits for a per-phase reviewed INSERT (deletable per phase). And the lock every crew discovers the hard way:

Note: During cruise, whenever uplink wind data is received and not inserted or cancelled on the CRUISE WIND page, access to the DIR TO function is not possible. The WIND UPLINK EXISTS message is displayed on the scratchpad.

An unhandled cruise wind uplink locks DIR TO — before accepting ATC's direct, settle the wind sheet (insert it or cancel it) and DIR TO unlocks. (Uplinked winds for surplus fixes are discarded silently.)

The downlink side (per AMM 22-76): four flight reports — the position report (automatic over ground-designated fixes, ground-requested, or manual — the manual trigger AMI-disableable), the progress report (ETA plus destination EFOB; triggers AMI-defined: minutes to T/D, minutes to destination, ΔETA — and no manual send key exists), the F-PLN report, and the performance report (ground request only) — plus 19 broadcast items flowing routinely to the ATSU, including AP-mode and flight-phase discretes: the company's ground system can, in effect, see your FMA.

3. The ATC side — CPDLC and ADS

The route clearance's SEC channel (per AMM 22-76): the crew builds the desired route in SEC and downlinks the request; ATC's answering route arrives on the DCDU, and LOAD stores it into SEC — CPDLC never touches the active plan directly; review, then ACTIVATE SEC (the same philosophy as the AOC in-flight plan uplink). Message families: cleared-route/position-cleared/cleared-via uplinks, and the time-constraint set. Automatic answering: conditional reports answer themselves when the condition is met; the ATC position report auto-sends at each sequenced ATC waypoint (17 items; climbs/descents attach their level-change messages; an active offset attaches its own message — ATC knows you are riding the offset); confirm-type queries answer immediately; and a deferred clearance hands only its condition to the FM, which announces 30 s before predicted satisfaction, then again at satisfaction.

ADS, four frames: the basic frame (position plus quality) refreshes every second; the predicted-route, intermediate-intent (next altitude/track/speed change point) and fixed-intent frames every 10 s — how ATC "sees" you beyond radar. The ATSU manages the contracts; the FM just broadcasts on schedule — from both FMs (the exception to the communications master).

ATIS (the FM's ATA-46 neighbour). Per FCOM DSC-46-10-50:

The ATIS is automatically sent to the aircraft, when ATIS information is updated.

— per-airport SET ON auto-update from the ATIS MENU page; UPDATE CANCEL returns it to manual request.

4. Printing — three reports and their clocks

Printing is independent of ACARS (no datalink needed to print FM reports). The three flight summaries:

• PREFLIGHT REPORT: after the complete plan and ZFW/ZFWCG are in, FUEL PLANNING run and BLOCK checked — print. Before printing, clear the discontinuities and enter all winds/steps/constraints/alternate, or the report lies. It becomes the flight's master monitoring document.
• INFLIGHT REPORT: printed at cruise with the latest clearance and winds in — history values for flown fixes, predictions for the rest; reprint after each major revision, each print replacing the previous as the new master; after a major failure (an engine out), another copy "time permitting".
• POSTFLIGHT REPORT: after shutdown — full history plus the fuel/time summary and the IRS drifts and ground speeds (article 20's landing drift computation, on paper).

Automatic printing (AMI defaults, page-adjustable): engine start → preflight report; takeoff transition → inflight report; shutdown → postflight report; uplinks may auto-print per AMI (titled FM UPLINK…); a dead printer answers PRINTER NOT AVAILABLE in the scratchpad. And the honest quirks the FCOM itself lists (so you read the paper correctly): headwind always prints 000°, tailwind always 180°; in pound units the historical FOB mis-prints tonne values; a DIR TO ABEAM's TO fix doesn't print — mis-printed is not mis-computed.

5. Operating the mouths

The three-step uplink rule (whole family): read the scratchpad to identify the type (AOC ACT/SEC F-PLN, TAKEOFF DATA, WIND UPLINK) → review on the dedicated page (read-only) → INSERT or CANCEL/CLEAR. The cost of leaving one hanging: a plan uplink blocks your TMPY, a wind uplink locks DIR TO.

Failure face: the FM DATA LINK UNAVAIL / NO ANSWER TO REQUEST message set (22 scratchpad messages in the AMM's table); a vanished request star = link down; the QRH computer-reset table includes the ATSU (article 29); and each function allows only one pending request at a time. Interfaces: uplinked plans in SEC (article 21); uplinked winds replacing a phase's old set (article 22); the TOW/TOCG gates leaning on the weight chain (article 25).

[!warning]- Four misconceptions this article corrects (1) "What falls from the sky goes in the drawer first" — after engine start every uplink lands in SEC or a read-only UPLINK page; the only auto-insertion is onto an empty table before start. (2) The INSERT key not appearing is the four gates working (runway/1 t/0.5 %/completeness) — parcel inspection, not a fault. (3) DIR TO refusing with WIND UPLINK EXISTS is not a lockup — settle the pending wind sheet and it unlocks. (4) The communications master and the guidance master follow different chains (ATSU bus versus AP/FD) — they may be different FMGECs, and ADS ignores both by broadcasting from each side.

Self-test

[!note]- Q1. Where does a flight-plan uplink go before versus after engine start — and when does the INIT REQUEST prompt vanish?

Before start: auto-inserted into the active plan. After start: routed into SEC for review. The request prompt disappears once an active plan already exists (and the star disappears when the FM-ACARS link is down).

[!note]- Q2. The four takeoff-data insertion gates — and what else happens when data with runway wind is inserted?

Uplinked runway ≠ active runway; TOW differing more than 1 t; TOCG differing more than 0.5 %; incomplete uplink — any one suppresses INSERT. Inserting with runway wind writes it as CLIMB WIND surface wind and retires TRIP WIND.

[!note]- Q3. Do wind requests follow the page or the phase — and can you request in descent?

The phase: preflight/takeoff = all four wind sets, climb/cruise = cruise/descent/alternate, descent and later = no request possible (a non-COPY-ACTIVE SEC is exempt).

[!note]- Q4. DIR TO is dead and the scratchpad says WIND UPLINK EXISTS — the fix?

Insert or cancel the pending cruise wind uplink on the CRUISE WIND page; DIR TO unlocks immediately.

[!note]- Q5. The full CPDLC route-clearance channel?

Build the wish in SEC → downlink the request → ATC's route arrives on the DCDU → LOAD stores it into SEC → review → ACTIVATE SEC. CPDLC never writes the active plan.

[!note]- Q6. The ADS basic frame's refresh rate — and which datalink output comes from both FMs?

One second (the route/intent frames every 10 s). ADS itself is the exception: both FMs broadcast, bypassing the communications-master rule.

[!note]- Q7. The communications-master decision chain — and is it necessarily the guidance master?

ATSU-FM1 bus READY → FM1; else FM2 READY → FM2; neither → none (independent/single: follows the guidance master). No — different chains (phone line versus steering wheel), possibly different computers.

[!note]- Q8. The three reports' automatic print moments — and which is the "master copy"?

Engine start → preflight; takeoff transition → inflight; shutdown → postflight. The preflight report is the initial master; each inflight reprint after a major revision replaces it.

[!note]- Q9. The consequence of a missing AMI file?

All ACARS functions are disabled — the airline-policy file is the master switch (26 individual switches when present).

[!note]- Q10. The postflight report shows headwind 000° — how do you read it?

As a known print quirk: headwind components always print 000°, tailwind 180° — mis-printed, not mis-computed (likewise the pound-unit FOB history and the missing ABEAM TO fix).

Key takeaways

References

Datalink architecture, AOC functions, report types and broadcast items, CPDLC message handling with the deferred-clearance notice, ADS frames and rates, the communications-master chain, AMI switches and the missing-file consequence, scratchpad message set and auto-print triggers per AMM 22-76 (attributed summaries of the description text). Flight-plan uplink routing, takeoff-data gates and the runway-wind side effect, wind-request phase rules and the DIR TO lock per FCOM DSC-22_20-30-80 (quoted verbatim). Print independence, the three reports, master-copy mechanics and the known print quirks per FCOM DSC-22_20-10-80. ATIS auto-update per FCOM DSC-46-10-50. The drawer/parcel framings are integrative syntheses.

Independent study material, not an Airbus publication and not endorsed by the manufacturer. Always defer to the current operator FCOM, FCTM, and QRH for operational use.