A340 ACM,s
 

I noticed a A340 grounded with a dual ACM seizure recently.I'm not familiar with the design of these components and wondering if operating in the middle east is responsible,there appeared to be a lot of fine silt throughout the unit which I'm thinking could play havoc with air bearing design.Any thoughts?

which 340-300 or 500/600, as the acm's are different? Not that it will make a lot of difference, They do both have a bypass mode, but it is done differently.
Environment will have an effect on the packs, perhaps the operator needs to review the AMS and get the packs checked/cleaned more often!

Check the MEL think you will find only one pack can be operated in standby mode

I know, didn't say they could both be in bypass mode at the same time.

Hewlett:

Never heard about double failure. Sitting in MCC ,we have normally no big issues with ACM's in common. But like You mentioned, cooling air is taken from the turbine inlet of the ACM to bleed the air bearings. It might be, that a long grd time can contaminate them, but like I told you , it is not common. My last time was 12 yrs ago on an A320, double seizure on ACM due to long GRD time before delivery. (long means 6 month) but also here , one by one , with a 2 week timeframe. AB went on warranty without any trouble, when back to work, I will look for a TFU, I remember there was one .

Rgds

h3dxb

Thanks for the interest.Said a/c may well originate from your location.H/x replaced also.I believe 1 pack was operating in bypass on arrival the other not operating.

We had a 330 arrive in UK from Middle East the other day with one ACM seized and operating in bypass mode. Happened in flight, upset the pax! Is there something in the air?:ok:

Dunny

Murphys law is true :} sent a AB to africa with an engine change crew due to high vibration and picked up on #3 Vib over limit for the incoming. So they stayed for 2 changes :ok:

rgds and all times happy airplanes:}

TFU for seized ACM's
 

Hewlett

Like promised , I checked for the TFU. (U can also check for it 21.52.21.012) It is not contamination of the airbearings, it is damage on the turbine due to ice impact. Reason is unsufficient water extraction on affected pack. We have at the moment 60-80% rH here. So make sure the water extraction pipe is clear :ok:

hope this helped

rgds