A320 run-ups

[705pilot]

Just been told by our company that we are to do a run-up prior to every takeoff in icing conditions (10c or less and visible moisture). So +10c and raining, we're doing a 30 sec run-up to 70% N1 in position using about 110kg of fuel.

We used to have 30 minutes of taxi time before this was required but now it's changed.

Any other airbus drivers doing this?

[BluSdUp]

Not Airbus specific if CFM56 engine. Answer is : NO!

[gnarlberg]

at my old company we did this when we really expected icing conditions. like freezing Fog n stuff.
airports would go crazy if you every time it rains at 5 degrees start doing run ups on taxiways or runways... In 12 months flying we maybe did 3 run ups...
Mostly you see in the turnaround if you have ice on the fan blades... then we ordered fan blade deicing and on the runway we did a short run up....

[705pilot]

Not Airbus specific if CFM56 engine. Answer is : NO!

Yes they are CFM56 engines but we've been told this is an Airbus specific directive. Apparently Boeing has a more specific (less restrictive) definition of icing on the ground. Airbus says if 10c or less and visible moisture a run-up is required.

[gnarlberg]

in our FCOM it says if we are in icing conditions more than 30 min we should apply ice shedding proc....

freezing rain freezing drizzle freezing fog heavy snow in 10 min cycles ice shedding...

[giggitygiggity]

Do you think this is going to be an Airbus directive for us all on the A320 then? I operate out of the busiest single runway airport in the world (Mumbai doesn't count!). The A320 is by far the most common aircraft to operate in and out of the airport. If every A320 has got to do a 30sec run up for half of the year then the airport is royally screwed. How on earth can this work?

We haven't been doing that for 30 years of A320 operation with the CFM so why now all of a sudden. Is that the reason for every engine failure?

[705pilot]

I guess "directive" is a poor choice of words.

Our FCOM is becoming much closer to the Airbus FCOM which is the reason for the change. Management blames Airbus by saying its their language.

Anybody have the most recent Airbus FCOM?

[Superpilot]

Does your company acknowledge this is outside of the manufacturer's operating recommendation or has someone misread the FCOM? Any incidents that the company is reacting too?

[Dct_Mopas]

I’m sure ground icing conditions, as described by Airbus, is below +10c with visible moisture reducing visibility to below 1600m (1 mile)

[705pilot]

Don't know if the Airbus FCOM is being misread as I don't have access to the latest version.

We've had some engine damage in years past but nothing I know of this year.

Dct_Mopas

Our definition (which they say is from Airbus) says:

"10c or less and any visible moisture (such as clouds, fog with visibility of 1 nautical mile or less, rain, snow, sleet, or ice crystals)."

So visibility of 1 mile or less only pertains to fog.

[lomapaseo]

Engine damage varies in cause and correction between engine models.

Basically the engine is design and certified not to be damaged from in-flight icing conditions. The presumption being that on-the ground the engine will not be dispatched with visible ice.

However, on-ground operations at low idle condition (sitting and waiting etc.) the depressed air temp inside the inlet (no-ram air) may form ice on the nose spinner, the fan blades or the compressor vane immediately behind the fan.

This ice may be shed during run-up conditions either by centrifugal forces (spinner or fan blades) or by windage effects against the compressor inlet vanes behind the fan. The RPM to effect this shedding (varies with engine model) must occur often enough that the ice that is shed does not visibly damage the engine nor affect its operation. Again even this latter effect varies with engine model.

Thus what turns up in your operating procedures may vary and is there to avoid situations shortly after aircraft rotation.

[BluSdUp]

I see You operate in Canada, possibly?

Time to read up on basic met stuff , Eh?

Have you ever had fan ice at say 9 or 5c pluss in icing condition?
I have not, but I have had at plus two in FZ fog , drizzle or rain.

And that brings me inside freezing conditions defined by visible moisture and 3c or less.

Last time I saw fan ice was the other week DH out of Oslo Gardermoen with minus 12 and a good 3 to 6 mm of solid ice on the back of the CFM56.
Took 10 minutes of hot air to thaw AND dry it.
2 chaps quite happy to do the job as they snuggled inside the engines.

This was picked up in the inversion that often forms there , on the approach.
Nothing on the way out as it was in my estimate 2km in -FZFG overcast 300`
As I recall it we did 40% , then 70% : No vib, all normal, TOGA.

There is some extreme instances at OSL ( Oslo) were they damaged some 8 or 10 engines over a 24 hr period due to fan ice. There is some reports out there.

Lastly, how do You use 120kg extra in 30sec at 70% N1, Dude , that is 13200kg FF/ hr.
The extra fuel used is marginal and the least of your concerns the day it counts.
No disrespect , but dig in the manual and pester your trainers!

[RUMBEAR]

705 pilot

Our FCOM is pretty much standard Airbus. It described icing conditions on ground as 10deg or less (OAT) and either visible moisture or contaminated ramp/taxiways. No reference to visibility below 1nm.

As you describe the engine run required before take off when icing conditions exist!

[705pilot]

BluSdUp

Actually I don't need to "read up on basic met stuff" as you suggest. Just need to follow the manufactures instructions on how to operate the engines. All I'm asking is for anyone who operates the 320 with CFM engines to let me know what their SOP is.

Yes now that you mention it 110kg seems way too high. Took that value from another captain's experience who posted it on our internal forum. Maybe he included some other delay.

I have "dug into my manuals" and I'm not satisfied with the answer. That why I'm asking here.

[ESCAT]

My company operates the CFM equipped A320s, and here is the guidance from the NOR.

"During ground operation, when in icing conditions for more than 30 min, the following procedure should be applied for ice shedding:

If ground surface conditions and the environment permit, the flight crew should accelerate the engines to approximately 70 % of N1 for 30 s at intervals not greater than 30 min. In addition, this engine acceleration should also be performed just before take-off, with particular attention to engine parameters to ensure normal engine operation."

I can see there is cause for confusion here, but it is interpreted as:

If you are in icing conditions for MORE THAN 30 mins, you need to do a run-up every 30 mins, as well as immediately before takeoff.

If your taxi time is LESS THAN 30 mins, no runup is required.

The note "In addition, this engine acceleration should also be performed just before take-off..." is still under the header of "During ground operation, when in icing conditions for more than 30 min" so it only applies if you are more than 30 mins taxi out time.

Under 30 mins, no runup required.

Of course management could have come up with more restrictive guidelines based on their operational experience, or they could have misinterpreted the guidance from the Airbus FCOMs, in this admittedly poorly written paragraph.

[705pilot]

Thanks ESCAT! Exactly the kind of answer I was looking for.

Thats how we used have it written as well. Not sure why the change. Frustrating...