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320DRIVER
26th Apr 2004, 17:25
Do any of you guys use PACKS OFF Take-off as the standard procedure on the Airbus SA family?

If you also use the standard ICAO noise abatement procedure i.e. reduce thrust at 1500 AAL and accelerate at 3000 AAL, did you find a way to tweak your procedure to avoid the AIR PACK 2 OFF warning which is triggered if the standard Airbus SOP is followed i.e. PACK 1 ON at THR RED, and PACK 2 ON at ACC ALT?

Airbus SOP also state that PACK 2 may be selected ON earlier and I wonder if someone has found the optimum procedure.

In $$$, what are the savings per take-off that one would expect by systematically using as PACKS OFF take-off?

Thanks for any feedback.

oldebloke
26th Apr 2004, 17:31
Some Co's do Packs/bleeds off as a standard.In the co's I was with it was an operatioal option(use if needed).Climb thrust ,at 1500AGL.one pack on either wait 10 secs second pack on to avoid the press' bump,or select second pack with flaps up. :O

idg
27th Apr 2004, 01:26
We use packs on almost exclusively, however we do practice the packs off technique during line training should it be necessary for any reason one day.

As per AI instruction we turn both packs on (sequentially) after thrust reduction and in most cases the warning is thus prevented.

By using packs off there will of course be an extension of engine life (lower EGT, higher flex...yes you can flex packs off) as long as you are not performance limited. Trying to quantify those savings would, I suspect, be very hard to do and would depend on the kind of operation being undertaken.

We have just removed an engine with 6000 hrs and 12000 cycles from the wing where it had been since delivery. The only components that needed replacing were some of the first stage hp compressor blades (one of which was damaged) and was rebuilt and is ready to go back for more. Not bad life I reckon for our shorthaul kind of operation. Note that there was no turbine blade replacement which one would have expected if our engines were under undue stress. :ok:

Torque2
27th Apr 2004, 10:49
Our company SOP is for packs off on take off. We reduce thrust at 1500 agl and then select both packs on with a 10 second delay between 1 and 2, accelerate is at 3000 agl. Can't answer your question re cost saving but the performance gained is significant. ;)

Pegasus77
27th Apr 2004, 10:53
We have packs on; only when the FLX would be lower than 45 deg. we would switch them off for takeoff, to get a higher FLX temperature.

IMHO it is not comfortable for the pax to have an unpressurized takeoff, followed by a quick pressure buildup around 2000'.

P77

BRAKES HOT
27th Apr 2004, 13:05
in my company packs off is the standard for t/o as per torque2's explanation. if we need to use packs on a hot day the apu bleed can be used for take off assuming the it's not inop.:)

Pegasus77 is that because you use CFM56's? i seem to remember Tmax is 44 or there abouts. the v2500 lets you go a bit lower.

Pegasus77
27th Apr 2004, 17:52
Actually, we have both types of engines (V2500 on the 321, the CFM on 319/320) and use the same procedure on both.
The only reason is to prevent engine wear. As our technical pilot states: The most important FLX-degrees are the first ones... Meaning that the difference between FLX56 and FLX58 is almost nothing compared to the difference between FLX39 and FLX41.

For pax-comfort we takeoff with packs on, only if the FLX becomes below the said 45 we switch them off. And even then some captains don't like to do that, and leave them on for pax comfort, if we don't need them for performance.

P77

Capt Chambo
27th Apr 2004, 18:43
It is sometime since I flew the A321/320, but I do recall that there was a procedure buried in the FCOM where the APU is used to provide air for both packs. After take off one then simply turned the APU bleed off at a suitable time, followed by turning the APU off. The same procedure you follow basically after engine start, and it avoids all those ECAM warnings.

Boeing 7E7
27th Apr 2004, 19:13
Packs off in my company, and it is suppossed to save large amounts of money over the entire fleet over the year by reducing maintenance costs of the engine.

747FOCAL
27th Apr 2004, 20:09
Is this just how Airbus aircraft are flown or do Boeing operators do this as well? :)

qwertyuiop
27th Apr 2004, 23:31
My SOPs are for T/O with bleeds off. Its cuz the engines are crap and it saves them going pop. Its not cost cutting cuz the other fleets dont do it. Not actually an airbus prob, just shi# engines.

OPEN CLB
28th Apr 2004, 16:35
SOPs are packs off. Switched off during line-up, turned on again after setting of climb thrust.
If we decide we need the packs for whatever reason, its packs on engine bleed, nothing else.
Engine bleed off or APU bleed on might work fine as long as you don't encounter icing conditions. APU bleed is not authorized for wing anti-icing, as it simply does not supply the required temperature. Engine bleed off is self-explanatory. This might pose a risk in a high workload / stress situation.