Switch off engine anti-ice during de-icing?

[PENKO]

Hi there!
As usual, apologies if this has been discussed earlier.
I have a question which came up recently.
Do you need to switch off the engine anti-ice during de-icing on the ground?

The Airbus 320 FCOM clearly states that you should prepare the aircraft for de-icing by closing the bleed valves, pushing the ditching button etc. All very good. But what about the engine anti-ice when you de-ice with the engines running in icing conditions? Should you switch those off also so as to prevent fluid ingestion in the cowl anti-ice system? Or do you leave it on to prevent ice buildup on the engine?

I can't find any reference to this..

[Rubis]

The current Company I work for has ENG A/I off as the second step of the "ENG RUN DeIce procedures.

[rubik101]

Short answer, YES. Even if your manuals don't mention it specifically, common sense tells you that sucking de-icing fluid into the air systems, whether they be engine or cabin systems, is not to be recommended.

[a5in_the_sim]

I don't fly this type but other jet types I know have the engine anti-ice bleed valve upstream of the normal bleed valve. This means that the engine anti-ice bleed supply is not effected by the engine bleed valve selection.

Engine anti-ice or lip anti-ice is switched/controlled by a separate valve. In the event of electrical failure it is common for this valve to fail "OPEN" so that this de-ice function is not impaired.

It would be worth consulting the pneumatic schematic for the type to see if this is the case.

The main reason for deselecting the bleed source is to prevent contamination of the bleed air gallery with de-icing fluid, especially as this air supplies the cabin via the packs (normally).

At the end of the day....follow the instructions in your type specific manuals...they may constitute an aircraft limitation.

[PENKO]

Thanks for the replies so far! Indeed common sense might dictate that anti-ice is to be switched off but I am very surprised this is not mentioned anywhere (as far as I know). However, bleed air is always extracted anyway for engine turbine cooling etc. So maybe it is not such a problem anyway to keep the anti-ice on?

My worry is still sitting there in heavy icing, with engines running for a good ten minutes whilst the airframe is being de-iced without any ice protection for the engines.

a5-in-the-sim, we have similar engines (CFM)

[woodywood]

If Airbus FCOM does not ask to switch them off, then keep it, also it needs to be extremely freezing to form ice on the intakes when standing still.
Happy Xmas!

[The Bartender]

If the conditions are that bad, might i suggest beeing towed to the de-icing area, or at least have them shut down during de-icing?

Just yesterday i had a Fokker 100 visiting me for a bit of de-icing, in FZFG, and during the treatment, the crew complained about vibrations in the engines.
I offered to have a look at the fans if they shut them down, and guess what..

During the short taxi to the de-icing area, and during the treatment, the fanblades picked up a layer of 5-10 mm's of ice behind the fanblades...

As we had no equipment available at the de-icing area to remove the ice, i suggested they return to ramp to have it taken care off...
The crew agreed, started back up again, and departed... :rolleyes:

[FlyMD]

We have the same engine as a F100, and our manual suggests, for taxiing in icing conditions, to periodically run the fan speed up to 60%, to avoid ice accumulation behind fan blades...

It has been my assumption that the same procedure applies if a fan that's icing up starts to vibrate... if a short run-up of power gets rid of the vibration, fine, otherwise investigate further..

Have I been to cavalier in my attitude to fan-blade icing?

[Clarence Oveur]

Engine anti-ice, which is perhaps a somewhat misleading name, does not affect the fan blades. It is not uncommon for ice to form on the back of the fan blades in cold and humid conditions. This will happen after engine shut down where condensation will form and eventually freeze. Engine anti-ice will not prevent or remove this. The fan should be checked before start and any ice removed. If fan icing is suspected during taxi the ice shedding procedure must be used. Most aircraft also have a requirement for engine run-ups at specific intervals when taxiing in icing conditions for this very reason.

[Canuckbirdstrike]

The company I work for specifically directs that engine anti-ice be on during live (engines on) deicing. The logic behind this is that any deicing fluid spray that inadvertantly enter the engine may cause blead contamination, but by using engine anti-ice it is purged out through that system and with the bleeds off the likelihood of bleed system contamination is very low. This reduces the chances of air conditioning system contamination and problems after takeoff with cabin air quality.