A320 Engine failure packs off takeoff

[Speedwinner]

Hello folks,


i have a question: always fly packs on for takeoff in our company (except performance does not allow it) so i never actually thought about the pack management in case of a engine failure after go. How do you do it exactly? During acceleration there will be the pack warning on ecam right? but which may we switch etc? Any publications on that?

[bigfatchris]

I haven't seen anything on it either.

We had a similar situation positive climb, rotate, thud thud.

Having had a birdstrike in one engine, after PF had stabilized the aircraft, and above acceleration, I as PNF announced that I was about to turn on the unaffected engine's pack, and said I would hold on the other. We agreed on that and did it. We got the ECAM caution about PACK x OFF, and a few minutes later with just high eng vib on one side, we elected to turn the pack on.

It didn't present us with any problems as it was mainly N1 rotor damage, and not a full shut down. No one smelled roast chicken.

Engine damage was 3 bent fan blades and unknown damage to the hot section - I think it was very minor. The vibs were high enough to warrant digging out the QRH and diverting.

Has anyone else experienced similar, or different with engine trouble and pack operation? I would be interested too...

[rudderrudderrat]

Hi Speedwinner,

If you've done the performance calculation assuming packs off and suffer an engine failure, the you shouldn't turn on the 1st pack until after the first thrust reduction (MCT).

Just one pack selected on the operative engine side keeps ECAM happy. If you open the cross bleed, then ECAM will invite you to turn on the second pack.

[TSIO540]

My FCOM PRO-NOR-SOP "Takeoff" section says "at acceleration altitude, set thrust levers into the climb decent then select pack 1 on and then select pack 2 on (if applicable)" which says to me judgement may be used - I.e. should you be doing a flight test, complying with a MEL O procedure or a depress ferry you may configure as desired.

Depending on your MSN number, the later model Bleed Management Computers (BMC) will automatically close the affected bleed if the engine is shut down so pack selection in that case would be irrelevant unless the cross-bleed was set to open for some reason - MEL?

With the cross-bleed switch in 'auto', IIRC the cross-bleed will be closed and the affected pack inlet valve will close automatically or in this case remain closed.

In all models it is my understanding that the BMC will close the affected engine bleed if there is reverse flow through the bleed valve (I.e. of a failed engine), so again in this case (failed side) pack selection would be irrelevant.

Following the failure, if a pack was necessary, it would be logical to me to switch on on a pack on the serviceable side and change bleed switches only as directed by the ECAM or QRH.

[Uplinker]

Implied, but not stated so far, is that an engine failure can contaminate a pack and the pneumatic ducts, with oil and other nasties, which could lead to fumes in the aircraft.

Therefore, one should think very carefully before switching on the same-side pack of an engine failure, or even of opening the cross bleed valve to feed both packs from the good engine, because contamination could then get through. Be warned: the ECAM does not consider contamination, and may invite you to configure the pneumatics to feed both packs.

[vilas]

Uplinker & RRR
If engine failed with damage then you would have pushed the fire button. ECAM will only ask you to open the Crossbleed if fire button is not pushed and wing anti ice is off that too performance permitting. Even without damage good idea to consider single pack operation. If it is after take off then one could do without second pack.

[rudderrudderrat]

Vilas
ECAM will only ask you to open the Crossbleed if fire button is not pushed
That's very odd because ours shows the following even if ENG FIRE PB has been pushed.

http://www.blackholes.org.uk/PP/Start%20valve.jpg

[OPEN DES]

Hi RRR,

The caption you show is displayed on the ECAM after the ENG FAIL in the CAE sims. It is usually cleared as spurious.

What Vilas implies is the line on STS (when ENG FAIL NO DAMAGE)

If performance permits:
X-bleed..... OPEN (to restore (symmetric) wing anti ice)




Rgds from an orange

[vilas]

RRR
What OP Des say is correct. It is spurious it has nothing to do with engine fail. It should be cleared.