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A320 Excessive Hot air cabin

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A320 Excessive Hot air cabin

Old 1st May 2015, 09:28
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Question A320 Excessive Hot air cabin

The other day, in cruise the FAs come in and say excessive hot air coming in the cabin, we turn the temperature down, then the indication was cold air coming in. So much heat with the trim valves in the standard positing on the panel.

Later in the flight more complaints of hot air, 36 degrees,

We turned the hot air valve of course. The problem stabilized with the Hot air valve off.

Investigating with maintenance the problem, we suspected the sensors were dirty, but found that they cleaned them 4 days before.

The engineer suspected the zone controllers ? another said it was the sensors but they cleaned them 4 days before? What could be causing this ?
Dirt in the zone controller duct?

Any thoughts from pilots and engineers ?

Thank you in advance for your help and thoughts, on this one.
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Old 2nd May 2015, 10:02
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I've encountered the same problem in some of my flights. The implicit SOP in our company is to switch the HOT AIR Pb off. Recently, I found a senior training captain resort to pulling out a couple of CB's in the rear panel and resetting them, thereby solving the issue. If I remember it right, those were the cb's with the label ZONE TEMP CTL sys 1 & 2 in the rear CB panel. However there's mention of such a procedure in the QRH.
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Old 3rd May 2015, 11:39
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What was the pack outlet temp on the system display??

Failed ACM??
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Old 4th May 2015, 16:08
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It looks like a as very familiar story for me..FF aircraft? I still don't have easy answer what can cause this scenario...but cabin sensors and its inlet ducting,including hose upstream of sensor housing are only mentioned in relevant troubleshooting procedure (Actual Zone Temperatures are above Selected Zone Temperatures (In Flight)). If is high temp limited to cabin and normal in flight deck blockage in sensor inlet ducts can be root cause. Monitoring of zone trim valves position and pack output in flight and comparsion with normal A/C can be very helpful for next steps. I wish quick-effective solution and would like to know the outcome.
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Old 5th May 2015, 01:31
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My first line flight in the A320 I encountered this problem. We were just airborne and extremely hot air started pumping out of the flight deck airvents and within a minute or so the zone temp was saying 40 plus in the flight deck with the cabin also climbing. We turned off the hot air valve which seemed to stop the increase but we couldn't get the temp down. In the end we had to turn the packs off and use the ram air as both the Captain and I thought that we were going to faint, a quick return to departure was made. After much investigation the engineer couldn't fault any component of the air system and the aircraft was dispatched later in the day with no further problems. It was a very uncomfortable experience.
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Old 5th May 2015, 07:50
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I used to experience something similar on 737s, the controllers would agressively overcompensate with either freezing cold or uncomfortably hot air - could be fixed easily during the turnaround by releasing the grills from the cabin temperature sensors with a paper clip and then giving the foam filter a good shake!

€: On the 777 we recently encountered an improperly deactivated zone trim valve, it was left half open (when it should be deactivated closed), raising the temperature in the forward economy section to above 30 degrees... We couldn't do much except cycle the related trim air valve to keep the temperature within comfortable limits while keeping the other zones happy...

Last edited by STBYRUD; 5th May 2015 at 09:24.
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Old 5th May 2015, 09:23
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I have had the case with extremely low temperature ,where the temperature dropped to 5 degrees without any fault or warning.
Surprisingly by switching off just one pack , the temperature started to rise sagain , and was back to normal for the remainder of the flight. This is not a procedure but it avoided a diversion.

In the old days there was a procedure on QRH "too hot too cold ... "Not sure about the name
This procedure asked the flightcrew to swich off one pack in case of too hot or too cold. This procedure is not actual anymore but practically it still gives positive results
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Old 6th May 2015, 05:08
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Ask the engineers to check the pack filters too. You get hot cabins esp with full pax loads if they haven't been replaced a while. Replacing takes 10 mins tops on Airbii.
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Old 6th May 2015, 10:48
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For info, switching off the APU and using ground air conditioning can cause the cabin to get a bit stuffy once you are back on the APU. If the external air is excessively cold it will chill the sensors and the aircrafts air conditioning will start supplying hot air to bring the temperature up to the commanded position once it's back on.

If I've been on external air, I turn the temperature controls to full cold and bring them up gradually.
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Old 13th May 2015, 10:37
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A320 Excessive Hot air cabin

It's quite a common problem on the ground, especially if it's the first flight of the day. I have no idea what causes it but cycling from external powers to APU power often fixes it, although sometimes it may take a couple of goes.
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Old 18th May 2015, 19:06
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QRH Procedure still valid on our oldest A321 Lady:


Apply the procedure if the cockpit and cabin temperature become too hot or too cold with the temperature selector at its maximum cold or hot selection :
PACKS OUTLET TEMP (ON ECAM BLEED PAGE).......................................CHECK
 If difference between both packs is below 10 C:
AIR COND HOT AIR switch...................................................... .......................OFF
A difference between both packs lower than 10 C may reflect a mixer temperature sensor failure. Switching OFF the HOT AIR results in the use of the duct temperature sensors only and no longer in the use of the mixer temperature sensors. A normal cabin and cockpit temperature will be recovered.
 If difference between both packs is at or above 10 C:
PACK (WITH THE HIGHEST OUTLET TEMP)............................................... OFF
A difference between both packs of 10 C or greater than 10 C may reflect a contamination of packs resulting in too hot cabin and cockpit air temperature. The situation may be alleviated by switching OFF the pack discharging the hottest air.
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Old 20th May 2015, 13:28
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N.L.: Thank you for your valuable input!
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