Embraer Performance Question

[FlyChicaga]

This question was posed to me today, and I'm curious what others think.

If you depart with the Anti-Ice in the ENG position, but do not expect to get ice on takeoff (strictly for contaminated runway), must you enter Anti-Ice ON on the takeoff data, and must you take the performance hit?

 

[flatspin7]

I would think that you would have to take the penalty for 2 reasons-


1) If you have the override switch in auto you will get an Ref Anti-Ice Disagree message

2) With the engine lip anti-ice on the bleed valve is open and you have the performance penalty- Even when taking off into ice you still only have the switch in ENG not ALL.

Thats just my $.02

 

[LJDRVR]

Hey M,

I'm just another dumb probationary FO like yourself, but I think that flatspin is correct. There's a distance penalty for both runway and climb. My take on that is the loss of performance is less bleed air equals longer takeoff run with decreased climb performance, regardless of whether or not icing conditions are encountered in the initial climb.

Just my .02, there are folks on here far more clever than I.

Cheers!

 

[FlyChicaga]

My take:

If you are going to have the Engine Anti-Ice on for takeoff, then you are going to need to a) take the performance penalty, b) enter it in the takeoff data, c) configure properly with engine bleeds on, packs off.

But I've been led to believe you can depart with the APU bleed open, engine bleeds closed, packs on, engine anti-ice on, no takeoff data for ice-on, and no performance hit. I just don't see how this is the case. So, hence me asking. Reason being that you won't encounter ice on the takeoff or climb, except for slush or lose snow remaining on the runway. But even for this, I'd say engine anti-ice should be used properly.

 

[flatspin7]

I'm not sure if the APU puts out enough bleed air for the anti-ice system, plus Its simply an improper configuration... No where in the book does it mention doing that.


Honestly 99% of the time I find that were landing structual limited and the anti-ice performance hit doesn't come close to factoring into anything, especially on any runway longer than 7500 feet.

 

[millhouse21]

If it's just a matter of engine anti-ice, then it shouldn't really be a problem to take off with the apu running the packs and the engine bleeds off. The reason is that the engine inlet anti-icing valve is upstream of the bleed shut-off valve. Thus, the engine anti-ice will still work with the engine bleeds closed.

Having said that, your SOP may say something different about the desired configuration. Also, you will want to have the engine bleeds on before entering actual icing conditions (obviously).

 

[Flechas]

I think that you would have to take the penalty for the weight because you are still taking bleed air (read thrust) from the engine, even if you have the engine bleeds closed. As far as the take off data, if it is only for contaminated runway, you could probably enter off, because you are not expecting to open the wing anti-ice valve. Also, since you are taking off with the engine bleeds closed, if you enter ON on the take off data, you will get an EICAS message related to wing anti-ice fail (APU bleed not enough for wing antii-ice).
So, taje the performance hit but do not enter Anti-Ice ON on the take off data.

Flechas

 

[TheRaven]

But I've been led to believe you can depart with the APU bleed open, engine bleeds closed, packs on, engine anti-ice on, no takeoff data for ice-on, and no performance hit. I just don't see how this is the case. So, hence me asking. Reason being that you won't encounter ice on the takeoff or climb, except for slush or lose snow remaining on the runway. But even for this, I'd say engine anti-ice should be used properly.

The wing/stab A/I system will come on with the selector in ENGINE at wheelspeeds above 25kts if the ice detectors sense ice, but you will instantly get the STAB and WING A/I FAIL, as they will not have adequate air supply from the APU.

So to preclude this from happening and getting a Caution message during climb it would be easier to just open the engine bleeds, select Ref A/I on, and close the apu bleed and packs for departure til you are in the air. Anyone who configures the system as you had asked about is over-riding the purpose of the Ice Detectors and needlessly inhibiting the wing and stab a/i system.

 

[rattler]

My take:

But I've been led to believe you can depart with the APU bleed open, engine bleeds closed, packs on, engine anti-ice on, no takeoff data for ice-on, and no performance hit. I just don't see how this is the case. So, hence me asking. Reason being that you won't encounter ice on the takeoff or climb, except for slush or lose snow remaining on the runway. But even for this, I'd say engine anti-ice should be used properly.

100% False, TheRaven is right.

 

[nimtz]

Ah Matt,

We have a training department for these questions. Why don't you just call or email them and ask somebody whose opinon OFFICIALLY matters. Trust me they want your questions and they want to help you learn the company way. Getting anon opinons on the internet does not promote standardization which our airline sorely needs.