MEL Dispatch (ATA-46)
Dispatch with an information-systems item inoperative follows the operator's Minimum Equipment List. The exact categories, numbers and provisos are operator-specific — this article teaches the logic of ATA-46 dispatch, not any one operator's numbers. Always defer to the current operator MEL.
The ATA-46 dispatch logic is unusually uniform: a datalink item may almost always be dispatched inoperative (datalink is an aid), at the cost of — ATC datalink unavailable, revert to voice, RCP/RSP performance lost, no FANS-mandated routes, and no 4D operations.
1. The uniform datalink dispatch pattern
The datalink items — the ATSU, the DCDU, the ATC MSG pushbutton, the ATC datalink — are all dispatchable inoperative, with a common consequence:
- ATC datalink applications (ADS-C, CPDLC, DCL, OCL, D-ATIS) become unavailable;
- the RCP (CPDLC communication performance) / RSP (ADS-C surveillance performance) capability fails (see FCOM DSC-46-10-10);
- for a 4D-capable aircraft, 4D operations are not allowed;
- where the procedure requires ATC datalink, another means of ATC communication is required (voice); on routes not requiring FANS A capability, ATC may permit voice.
[!warning]- Dispatching a datalink fault means you cannot fly FANS-mandated routes The datalink item itself is easy to dispatch, but do not forget the route requirement (article 10): the published FANS route networks require FANS 1/A (for example the FANS routes over China — Y1/Y2/Y3/L888 — per GTG-FANS), and some North Atlantic routes carry a datalink mandate. Dispatching an ATSU/ATC-datalink fault = losing FANS capability = those routes cannot be flown — only an alternate route not requiring FANS A, on voice. So the ATA-46 dispatch question is not "can this item be dispatched?" but "does this flight's route need FANS?" — on a FANS-required route, the datalink becomes effectively required. This is MEL coupled to route (as with ATA-23's external-voice dispatch).
2. Redundancy — keep one of two
The DCDU and the ATC MSG pushbutton are each installed as two, required as one — one may be inoperative (the other covers), and only losing both triggers the "procedure requires / does not require ATC datalink" split.
3. Company datalink — tied to SATCOM voice
The company (AOC) datalink may be dispatched inoperative, with one hard proviso: SATCOM voice must be working — preserving the voice link to the company (the same "a dispatchable item needs a working substitute" as ATA-23).
4. The EFB is not a MEL item
The EFB itself is not subject to the MEL — it is an operational aid, and its dispatch is not governed by ATA-46 of the MEL (follow the operator's EFB policy / operations manual). The EFB external power supply is separately dispatchable.
5. The lines of dispatch logic
Line one: datalink is almost always dispatchable, at the cost of voice-only and lost FANS. ATSU/DCDU/ATC MSG pb/ATC datalink can be dispatched, but ADS-C/CPDLC go unavailable, RCP/RSP fail, and no 4D — of a piece with article 11's "datalink fault = crew awareness = revert to voice". Dispatching a fault is accepting "this flight is voice-only ATC".
Line two: keep one of two. DCDU and ATC MSG pb are two-installed, one-required — one may be inoperative.
Line three: company datalink is tied to SATCOM voice. A dispatchable company-datalink fault requires SATCOM voice working — a working substitute.
Line four: the EFB is not a MEL item. It is an aid, dispatched per operator policy, not MEL-46.
In one line: ATA-46 dispatch = "datalink is an aid, so dispatch it and go voice — unless the route needs FANS."
Self-test
[!note]- Q1. Which ATA-46 item is not a MEL item? The EFB itself.
[!note]- Q2. Can the ATSU / ATC datalink be dispatched inoperative, and what is the cost (ADS-C/CPDLC, RCP/RSP, 4D)? Yes; but ADS-C/CPDLC become unavailable, RCP/RSP capability fails, and 4D operations are not allowed.
[!note]- Q3. Why does dispatching a datalink fault mean you cannot fly the FANS route networks (e.g. Y1/Y2/Y3/L888)? Those routes require FANS 1/A; dispatching a datalink fault loses FANS capability, so only alternate, non-FANS routes on voice can be flown.
[!note]- Q4. DCDU / ATC MSG pb — installed/required? What is the hard proviso for dispatching company datalink? Two installed, one required (one may be inoperative). Company datalink dispatch requires SATCOM voice working.
Key takeaways
| Point | Detail |
|---|---|
| Datalink | Almost always dispatchable; cost = ATC datalink unavailable, RCP/RSP lost, no 4D, voice-only |
| Route coupling | Dispatching a fault = cannot fly FANS-mandated routes; ask "does the route need FANS?" |
| Redundancy | DCDU / ATC MSG pb: two installed, one required |
| Company datalink | Dispatchable, but SATCOM voice must work |
| EFB | Not a MEL item |
| Defer to operator | Categories/numbers/provisos are operator-specific — use the operator MEL |
References
- Operator Minimum Equipment List, ATA-46 — the authoritative dispatch conditions (operator-specific; not reproduced here).
- FCOM DSC-46-10-10 — RCP/RSP performance; the mechanisms behind the dispatch logic.
- GTG-FANS — FANS route mandates behind the route coupling.
Independent study material, not an Airbus publication and not endorsed by the manufacturer. Dispatch is governed by the current operator MEL; always defer to it and to the operator FCOM, FCTM and QRH for operational use.