A-320 Using of Engine anti-ice

[PENKO]

Ok, before we get hopelessly confused, which is not very hard on an Airbus, what is this talk about half deflection being available with autopilot on? All it says in my (edit: A319) books is that you get half rate when flying faster than .75/315 with AP engaged. No more, no less.

The part about anti-ice, with airbus one must be always very suspect of translation vagueries (French to English). I know, a dangerous statement, but not less true.

[SoundLesS]

1.27.10 P11 bottom it tells about AP spoiler deflection being achieved with half speedbrake lever deflection.

[PENKO]

Ok thanks, can find no such note in the A319 FCOM. Forgive the confusion.

edit

I compared the 319 FCOM with the generic FCOM. There is less speedbrake authority on the 319. And no distinction between manual and autoflight.

[wingattack]

In my company we do not turn EAI on in the descent until just before entering moisture (say 10-15 seconds before). Is this wrong? Should it be on for all the descent/hold if the only moisture anticipated is a layer of FZFG?

As an aside and please excuse the thread creep.... Found myself very high once in an A320 so decided to select full speed brake and disconnect the AP. Cabin crew rang from the the back galley thinking the tail was about to fall off; shan't try that again!

[DesiPilot]

Penko,

In A319 and A321 you will get full speed brakes even with A/P engaged whereas in A320 you get half the speed brakes only.

To achieve full speed brakes in A320 one must disconnect the autopilot!!

[PENKO]

Thanks for clarifying that! However when I compare the actual deflection of the control surfaces it seems that there is more deflection on the 320 than on the 319...so what is considered full speedbrake deflection on the 319 is actually half the deflection on the 320.

FCOM319 (1.27.10)
The maximum deflection for spoilers is :
25° for spoilers 3 and 4
12.5° for spoilers 2 in configuration 3, and 17.5° in other configurations
(NB , the same as on the A320 with AP engaged!!)

Whereas my generic A320 paper manual states someting like:
The maximum deflection for spoilers is :
40° for spoilers 3 and 4
20° for spoilers 2 in configuration 3, and 17.5° in other configurations


Sorry for the thread creep.

[TheGorrilla]

Can understand speed restricting spoiler displacement (?). However I fail to see why manually flying the thing should allow greater amounts of spoiler use. Particularly as the autopilot seems to have access to a higher roll rate than the pilot.

Ho hum... It seems that as I fly more hours my brain gets smaller.

[Dan Winterland]

Half speedbrake on the 320 is roughly equivalent to full speedbrake on the 321.

[TheGorrilla]

sounds like I should just accept this fact!

[manuel ortiz]

Girilla,

Edited after reading Airbus info.

A-320 was modified to deploy only half speedbrakes with A/P ON to avoid:

- Activation of AOA protection when starting emerg desc with A/P ON

- Posible overshoot of VMO at speed brake retraction with A/P ON

- AP pitch authority not sufficient to counteract the pitch up moment at full extension of the speed brakes

Best regards,

Manuel

[pakeha-boy]

Ok, before we get hopelessly confused, which is not very hard on an Airbus


after 15r yrs.....its easy

[Jonty]

The theory of below -40 is that all the moisture should be ice crystals and as such should pass through a fast rotating fan without adhering to the surface.

When in the decent not only are the stall margins of the engines much smaller but the fan is rotating much slower allowing ice to build up on the surface of the fan.

Its not just a 320 issue, we also did it on the 757.

As for the speed brake, all I know is you get half speed brake with the AP engaged on a 320 and full on a 321. Why? I have no idea!

[eight16kreug]

EAI is anti-ice so I agree it's a belt and suspenders thing. You asked for plus 1,000 kg fuel anyway, why not turn those heaters on? You don't want the ice until it's for the scotch at the hotel after the flight.

I pull the speedbrake lever when I need to kill the speed due to ATC restrictions. I've been hopelessly confused in the airbus for a long time so I leave it to the engineers to decide how many degrees they want to deploy which panels. (Aren't the speedbrakes those thingies that open up on the tailcone?)