A320 Eng 1(2) Reverser Fault

[Microburst2002]

According to FCOM 1: "Loss of thrust reverser on one engine, due to system components or input faults", no master caution nor single chime, just the ECAM caution. Inhibited all throughout the take off until 1,500 ft.

In the FCOM 3 there is an if line in small fonts. So I understand that only if that condition is met, the affected engine thrust goes to idle and the ECAM prompts you to retard the affected lever. It has a LAND ASAP, as well. If that condition is not met we just have the caution, with no ECAM actions ¿Is that right?

I don't understand this failure. What is the nature of the fault and the condition for the ECAM actions to be displayed?
"if reverser position fault with reverser pressurized"
Pressurized by the pilot? Does that mean that, having a reverser fault, only if we select that reverser we will have this ECAM actions?
But then... Why the LAND ASAP? can this failure occur in flight?
I find it quite confusing

[CJ1234]

Could you possibly make your question(s) clearer, and more coherent, and then I will be happy to try and help you.


1234:ok:

[Microburst2002]

Thanks CJ

Let me try!
I don't understand the ENG REVERSER FAULT.
According to the FCOM 1.70.90 p15, it seems a minor fault. No aural warning, no master caution. The failure description is that the reverser is lost, basically. No big deal. And it is inhibited until 1,500 ft.
However in FCOM 3.02.70 p1 you can see a LAND ASAP and the engine thrust locked at idle. This is big deal. This occurs only "If reverser position fault with reverser pressurized". Otherwise there is no idle protection and there are no ECAM actions.
After thinking a while, if there is an engine thrust locked in idle, this would trigger the ENG FAIL warning.
Anyway, I still don't know what is a "position fault". Reverser unlocked is covered in another caution.
I think the reversers are too briefly explained in FCOM 1.

[CJ1234]

Actually, you raise a very good point. It is poorly explained in the FCOMs. I've never thought about it before.

I shall ask around for any answers at work.

I'd be interested to know the answer.

1234

[Microburst2002]

:)Thanks again

[Slasher]

Micro I think it depends wether the buckets (cascades in Airboos-speak) are fully deployed or not. I cant work it out in those bloodey FCOMs nether. :ugh:

But cast back to the days when you flew Bill Boeing's machines. In the QRH it said "with buffet and yaw" and "without buffet or yaw". That determined wether your had a minor fault or a full-blown (aka Lauda 767) emergencey on your hands.

"If reverser position fault with reverser pressurized".
If you get a green REV on the upper ECAM on TO or in flight Id say your in deep poo. Otherwise a fault which may or may not give you a locked Idle.

[aristoclis]

My explanation:

No big deal if reversers not pressurized.

Reversers are "pressurized" if selected by pilot on ground in normal operation or if not selected by pilot on ground or air and some thing(s) went wrong. In that case thrust goes to idle and it is a big deal. (imagine reverser pressurized on ground during take off roll or in flight). In that case if in air, LAND ASAP.

Regards.

[TyroPicard]

The FADEC will automatically select idle thrust if the reverse thrust is not selected and:
The four doors are detected unstowed, or
At least one door is detected unstowed and hydraulic pressure is detected in the HCU, or
The door position is indefinite and hydraulic pressure is detected in the HCU

This is what is meant by the phrase "if reverser position fault with reverser pressurized". I suppose it may be a detection fault, or one or more blocker doors may actually be open, so the thrust is set to idle automatically.

If the reverser is not pressurised it is locked out and there is now no risk of deployment in flight (the no big deal case).

REV UNLOCKED: A reverser door can be unlocked but still be in the stowed position (no position fault).

[Microburst2002]

The three main REV ECAM cautions:

REV FAULT
REV PRESSURIZED
REV UNLOCKED

In case of PRESSURIZED (uncommanded but blocker doors closed and stowed) precautionary we have to retard the lever, except below 1,500 ft in take off, since it is inhibited. So it cannot be worse that an ENG FAIL at that height.

In case of UNLOCKED (uncommanded not locked and stowed) there are three or four degrees of severity:
- no idle protection activated (none of the conditions quoted by Tyropicard is met). There is no retard lever as a precautionary measure.
- idle protection activated (one condition met)
- same plus Buffet
- the damned REV is actually deployed, may God help us.
(of course there is no inhibition when idle protection is activated)

In case of FAULT (inop due component or input fault) accompanied by the idle protection (one condition met), not only the reverse is inop but it is pressurized and has a "position fault". However there is no buffeting nor deploying.

Maybe this is the case of the "indefinite position and hydraulic pressure" condition?

It is interesting that it is inhibited till 1,500 so it it occurred during take off roll or shortly after lifting off we would just have an ENG FAIL warning.

[aidey_f]

Sorry for showing my ignorance, but why would you get an engine fail message with a reverser fault?

[Microburst2002]

Hi

Good question!

If the idle protection is activated, the affected engine thrust will be reduced to idle. There is no caution regarding the reverser fault because it is inhibited, but (I thought) the ENG FAIL caution would be triggered when the thrust was reduced.
However, according to FCOM 1.70.90 p14 this caution is triggered when the engine core idle is below idle. I thought it was also triggered if there was a significant difference in n1 o egt or other parameters with respect to the other engine, but I don't know where I read that and the FCOM is the only valid source.
So if we have an idle protection below 1,500 ft due to a reverser fauld during take off we will sense the engine failure but the ECAM will be silent.

thanks

[747MC]

Folks, I think you are mixing apples and oranges here ..
Message: ENG 1 (2) REVERSE UNLOCKED
Condition: One or more reverser door are not stowed
position and a deploy order has not been given.
If on the ground:
• Place the ___ THRUST LEVER to IDLE.
• Place the ___ ENG MASTER switch to OFF.
• End.
Caution: In flight, the warning alone without buffet or vibrations may be a false warning.

Message: ENG 1 (2) REV PRESSURIZED
Condition: One reverser is pressurized. Reverser doors are
stowed and locked with no deploy order.

Message: ENG 1 (2) REV SWITCH FAULT
Condition: The reverser switch is faulty.
This is the message inhibited during t/o ...

Message: ENG 1 (2) REV ISOL FAULT
Condition: The reverser shut off valve is failed open.

An engine fail message is completely another subject and is triggered as stated above with the engine master switch in the on position and the engine rotating below idle speed

[Microburst2002]

Hi

What about the REV FAULT caution?

[Tinwacker]

This is the basic msg saying there is a fault, there could be a hugh number of reasons from wiring, relays, switches, latches, actuators, EEC ++++.
On the ground the engineer will find the associated msg that links to the REV FAULT and action accordingly.
Crew action might be awareness and that when on the ground the indicated reverser may not deploy.

REV POS is telling you that the reverser cowl might not be in the commanded position - buffeting expected, it could simply be a position switch out of tolerance and no buffet. This msg via the EEC would ensure that engine stays at idle dependant upon the logic seen.

FCOM is going to be very vague at telling you the full reasons as there are too many to mention in detail other than the AMM or TSM.

TW