Failures in A320 during CAT II/III approach

[IFLY_INDIGO]

Friends, where can I find the list of failures in A320, occurring below 1000ft agl during CAT II/III which demand a go-around?

Recently an examiner told me that during CAT II/III if MASTER CAUTION lights up below 1000ft agl due to NAV FM/GPS POS DISAGREE, don't go around, continue approach.

I always believed that any master caution below 1000ft on CAT II/III approach means go-around.

appreciate any help

[a350pilots]

It is a go around unless you are below the alert height of 100ft for a CAT3B approach NO DH.

[FlightDetent]

The Examiner seems to understand what's the job of flying in LVP about. Unfortunately, the FCOM says differently: Amber Caution (Single Chime) = GA.

Why? The LVP Getting to Grips explains: "simplified abnormal procedures, which are necessarily more conservative, are published in the FCOM." (when compared to AFM certification baseline).

The reason given for the GA below 1000 is that you do not have the time to re-assess the landing capability. But what if the failure is definitely NOT compromising the landing capability...? Such as VENT: Blower Fault
... at 820 ft?
... at 780 ft?
... at 220 ft?

What is the proper course of action? It is impossible to create a procedure (a decision making model in this case) for this. So a more conservative approach is taken.

---- to answer your question ----

Airbus FCOM has a simple rule that amber caution (single chime) below 1000 ft AFE requires the crew to go-around. There is no "approved-to-continue" list of amber failures.

Ironically, the logic behind the examiner's suggestion is valid. But if he was to train that, he'd just confuse the students and make a joke of the whole system.

[mcdhu]

PRO-NOR-SRP-01-70 should help.

[LW20]

Acc. Airbus you have to fly a Goaround between 1000ft and 200ft if there is an amber caution with single chime or a mode degradation (triple click).
But I think it's good airmanship to take a look and think about the amber caution. Will you go around if you get a fuel lo level caution in 500ft?

[vilas]

Once LOC is captured GPS/FMS plays no part in ILS approach whatsoever. So the examiner is not wrong. If you see PRO-ABN-34 P 13/30 NAV FM/GPS POS DISAGREE it says the following:

If the ECAM alert is displayed during ILS/LOC approach (LOC green):
Continue the approach
Off course if you went around you won't be faulted. You can assess the situation and make another approach. One Examiner telling a few pilots is not much of help. It should be incorporated in the SOP.

[Mungo Man]

...if MASTER CAUTION lights up below 1000ft agl due to NAV FM/GPS POS DISAGREE, don't go around, continue approach.


For this particular ECAM message, the QRH says continue approach. Obviously you'd have to have prior knowledge but when I used to fly regularly into an airport where NAV FM/GPS POS DISAGREE was common I would brief that we would continue if we were doing an ILS.

[FlightDetent]

May I suggest that the LVP SOP (and CAA approval for the operation) does override the ABN-NAV-34 "not displayed on ECAM" sequence?

I am afraid that following the rules on LVP abnormals means you need to G/A. If briefed beforehand - then ok, different story.

[sabenaboy]

"Rules are made for the blind obedience by fools, and as guidelines for wise men."

[IFLY_INDIGO]

I wrote to Airbus yesterday, seeking the clarification.

Airbus replied today and confirmed that a go around is required in the above mentioned case

[C.M]

I agree with FlightDetent. If you have mentioned this as part of a briefing you would make an exception .
It’s an interesting case of a failure : it is one that is unrelated to auto land capability ( it would not downgrade you from say CAT3 DUAL to SINGLE ) but it also happens to be one that is not inhibited by the LDG INHIBIT ( because it requires investigation if you had been using managed NAV ) .
The major thing to consider here is that it does not affect your auto-coupled approach and auto land , but should you go around at minimums you would not have time to assess if you could trust your NAV mode to manage you missed approach .
When Airbus advises you to Go Around in this case , it covers itself from any potential cock-up from considerations you have not briefed or thought about

[vilas]

IFLY_INDIGO
That's the way to go. Always consult the manufacturer. By the way which email do you use for tech request?

[IFLY_INDIGO]

company email id

[vilas]

I meant Airbus email id. Is it [email protected]

[ESCAT]

There is a lot of people referencing of the old FCOM blue diagram showing all the possible failure cases, and the associated actions. This has been removed as far as I can tell in the big documentation overhaul.

However, (At least for my company, perhaps it's tailored"), there is a simpler description of actions to be taken, located in:

NOR-SOP-18/ Aircraft Guidance Management /Approach Using LOC GS Guidance / Management of Degraded Guidance

Does everyone else have this in their new NOR as well?

It seems to give quite a good, simple explanation of what to do:

FOR CAT II, CAT III OPERATIONS
In the case of:
‐ Amber caution (single shime), or
‐ Landing capability degradation.

Above 1000 ft:
ECAM / QRH PROCEDURE................................................... ........ COMPLETE
REQUIRED EQUIPMENT................................................... ..................CHECK
Refer to QRH/OPS Required Equipment for CAT2 and CAT3
APPROACH AND LANDING CAPABILITY............................................ CHECK
If required:
RVR......................................................... ................................CHECK
DH.......................................................... ...............................ADJUST
BRIEFING.................................................... ........................ CONFIRM

If the flight crew does not complete all the above actions at 1 000 ft:
GO AROUND FLAPS....................................................... ........ COMPLETE


Below 1000 ft:

If external visual references are not sufficient:
GO AROUND FLAPS....................................................... ........ COMPLETE

Below 100 ft (Alert Height) for CAT 3 DUAL:
Approach may be continued unless autoland light comes on.

In the case of Autoland warning light:


Visual references not sufficient:
GO AROUND FLAPS....................................................... ........ COMPLETE

Visual references sufficient:
Approach may be continued manually

[IFLY_INDIGO]

for the curious ones :)