TAP002: The Air Conditioning System



29 Sep 2017 10:43 PM
I would not turn the remaining pack to off, because this would induce a depressurization. First I would start a descent and during the descent I would select warmer air in the regulator zones, reducing the remaining pack workload.
25 Apr 2018 01:28 PM
With a pack overheat, the associated pack flow control valve closes automatically in the event of a pack overheating (outlet temp > 260°C or outlet temp > 230°C four times in one flight). This leads to a slow cabin depressurisation since both packs are now off. If there are simultaneous faults with both packs as in this case, ram air can be used to control the depressuisation further. You would still need to descend to FL100 (or MEA if higher). If a PACK button FAULT light subsequently extinguishes (i.e. its now cooled down), an attempt should be made to reinstate that pack. Never seen what this would be like for real but maybe you wouldn't need to don the masks and carry out an emergency descent if this is diagnosed quickly. Not sure.
1 Feb 2019 10:44 AM
I agree with your statement about design flaw in not displaying if external air conditioning is connected or not. However, there is a way of finding out if it is connected or not. With packs not supplying air. Open the eye ball vent (next to the pfd) Turn off the cabin fans. If there is still an air flow out of the vent then external air conditioning is working. If not, then all air flow out of vent will stop.
3 Apr 2021 02:47 PM
I'd be interested to know whether my initial thoughts are correct please: 1. According to MEL, you can dispatch with one pack inop. 2. On receiving the AIR Pack 2 OVHT message (indicating the pack compressor outlet temp is above 260C) I would: * FNC (paying particular attention to MORA along route) * ECAM Actions which would likely lead us to turn Pack 2 OFF * A quick DODAR (assuming cabin altitude has not risen to unacceptable levels by now, otherwise O2 masks on next) * Call ATC to request descent to FL100 (or MORA if higher) * NITS or PA to pax (here I have prioritised descent over comms to keep cabin altitude safe) * When differential pressure is less than 1psi and below FL100 (or MORA), I would select the guarded RAM AIR pb to ON * Call to Company in case they want us to divert * Keep cabin crew and pax in the loop as decisions are made

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