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Flyman35
9th May 2009, 09:34
Yesterday I was on a flight to Europe the duration is 5:30 hours at FL 340 we experienced the following:
1-Pack 2 Regulator Fault.
……Hot Air OFF.

Now even if you put Hot Air On(it will not open) you are no longer able to control FWD and AFT cabin Temperature and all trim valves were completely closed the Temperature on cruise page was as follows 25 18 18 no further ECAM actions and No Further Paper work checklist.No blankets on the aircraft enough for the all passengers and the passengers start to feel cold.
For the next 60 minutes we were actually making a brain storming on how to solve such a problem or what to do, and all of a sudden a pilot who came up with an idea and said: what about closing Pack 2 it may let the computer senses that there is no longer a problem in the regulator and the computer may allow the hot air valve to open again) we discussed the solution and noticed that we are able to operate on one pack at that altitude.ok let’s give it a try ..pack 2 off …pingo Hot Air Valve is a life again , we continue as this for the rest of the flight with some fuel management (X-Feed) and during descent we put pack 2 on again, at destination maintenance were not able to solve the failure and as it is a minor failure and is not a no go item we departed back to other destination with 5 hours flying. when we arrived and start boarding again, now ECAM came up with pack the following:
PACK 1 FAULT …. And the rest of the actions. Now we lost both packs and we can’t depart in such a situation. passengers sent to the gate again and after 1:30 hours of Engineer Trying to fix the problem no progress happened. and all of a sudden we call our chef pilot who suggested a complete disconnection of the power evern the battery and leave the aircraft for 2-3 minutes to make a reset to all systems. again Pingo every thing is back no Faults and the two packs are working normal+HOT AIR valve and every thing.Thanks to Pprune because I’ve seen the reset solution before suggested by one the fellows here.
I learned about Airbus from that:
1-we can always use our minds to think and not to surrender to the computer all the time,remember you are the boss.
2-never be a shy to take advice of people who has little experience,be open minded, do a brain storming, discuss, evaluate and test if within safety limits.
3- A good understanding of the system helps a lot so don’t be boared from keep studying as they say here in my country say: (studying is the soul of science and knowledge).


My friends: please feel free to write any notes or suggestions; we are here to share our experience for the safety of our souls, our passengers and to light up the way for the next generation also.

hetfield
9th May 2009, 09:59
Yeah, that's bus driver's daily business.

Can't remember the 320, doesn't the ECAM say OFFr (OFF-RESET) ?

Sometimes it helps...

Shutting down the elec power incl. batteries on ground CAN also be avoided if you simply switch von APU GEN to EXT ELEC...and vv.



Regards

Landroger
9th May 2009, 10:21
All the usual disclaimers - I'm not a pilot nor even an aircraft engineer - I'm an MRI/CT Scanner field engineer, but on relevant levels of technology.

It is quite astonishing just how effective the old 'Power On Reset' gag is, with any and all computer driven equipment. Years ago, when computer control was rare or in its infancy, it was possible to know what the computer was doing at any given second - or even millisecond.

Now the computers are so fast and are multiplexing and multitasking at such mind boggling rates, it is not possible for anyone - not even the programmers - to know precisely what it is doing in any given microsecond. If only one of its inputs falls outside the expected range of numbers, the computer can confuse itself to the point where it looses the big picture all together. I imagine this is rarer in aviation products than it is in slightly less critical kit like mine, but computers are computers and they all suffer the same sort of electronic confusion.

Turning them off, leaving them for a short time to let all the capacitors discharge and CCD memories drain away, then turning them back on again can work wonders. Once a computer controlled device has 'glitched up' there really isn't any point in trying to work out exactly what has gone wrong - just POR the sucker. The problem with an aeroplane is; many systems are 'interleaved' and interconnected and it is not possible to Power On Reset individual systems effectively. The communications simply will not restart.

Plus, of course, it is not possible to Power On Reset the aeroplane in the air - only when it is safely on the ground and with hardly anybody or anything inside it.

Incidentally, we used to use a standardised inferface - a PPI, Programable Peripheral Interface - which could lock up so hard that a POR would not clear certain glitches. Only a POR followed by running a specific Diagnostic would shift and clear a particular form of hang up. That was spooky.

Roger.

Alteburger
9th May 2009, 15:44
Flyman,

This is an interesting problem. Our A320 FCOM procedure for AIR PACK 2 REGUL FAULT makes no mention of turning the HOT AIR off, though with loss of the Hot Air Regulating Valve, the Trim Air Valves are automatically closed. Depending on whether it is the pack Primary Channel, or the Primary AND Secondary channels of the Pack regulator which have failed, it does mention that the pack is at a fixed temperature. Mention is also made of the pack air inlet and outlet valves opening fully OR, the pack outlet temperature is regulated by the anti ice valve to a temperature of between 5 and 30 degrees C.

As Pack 2 serves the FWD and AFT cabin in the situation of loss of Hot Air Regulation according to the FCOM, whichever of the situations above it is, and all other parts of the air conditioning system being serviceable, you could assume that the lower than desired cabin temperatures are as a result of the fixed pack temperature from Pack 2. So, just by turning off Pack 2, you should still have a fully functioning and regulating temperature source from Pack 1 anyhow which will then serve the whole aircraft.

Flyman35
9th May 2009, 16:44
Our A320 FCOM procedure for AIR PACK 2 REGUL FAULT makes no mention of turning the HOT AIR off, though with loss of the Hot Air Regulating Valve, the Trim Air Valves are automatically closed
it is the same procedure in our FCOM, but the situation happened,there was a xx amber on the pack flow valve 2,the HOT air was closed,Trim air valves closed,when we printed the failure it said,temperature sensor fault.

batman123
9th May 2009, 17:44
you said youi have 25,18,18...
I would have let the cockpit door open to warm the rest of the cabin, still dont know if that's enough....

Alteburger
9th May 2009, 18:26
Flyman,
It sounds as though pack 2 had reverted to one of the fixed temperature modes (which was very cold!) and as you were getting pack 1 air in the cockpit, you were getting a much more reasonable regulated temperature in there. My thoughts were that by simply supplying the whole aircraft with Pack 1 output and having Pack 2 switched off, the whole aircraft should be regulated as normal at the selected temperatures rather than just the flight deck. Haven't had this fault so haven't tried it myself...!

hetfield
9th May 2009, 18:33
I would have let the cockpit door open to warm the rest of the cabin, still dont know if that's enough....

Perhaps it may get hot in the cockpit....:ouch:

Flyman35
9th May 2009, 20:08
My thoughts were that by simply supplying the whole aircraft with Pack 1 output and having Pack 2 switched off, the whole aircraft should be regulated as normal at the selected temperatures

that's what exactly happened as mentioned earlier we discussed the solution and noticed that we are able to operate on one pack at that altitude.ok let’s give it a try ..pack 2 off …pingo Hot Air Valve is a life again

guiones
10th May 2009, 01:04
Flyman:

You just became a wanabe Test Pilot(with passengers onboard); I hope you know more than the Engineers and TP's at Airbus that designed the 320 and developed procedures.

The interaction with all the computers and systems on Aibus FBW are very complex, so the advice is to stick to documented procedures. Shutting down a pack if ECAM or procedure does not call for it leaves you exposed to a lot of problems; legal and technical. All for temperature control!!!

If you think you have discovered a good way to improve a procedure, send it to Airbus and they will look at it and test it properly. Do not expose yourself and the passengers to your "ideas" if you realy care about safety.

I will send what you did to Airbus and get an expert opinion; it will take a while, but when I get it I will post it.

G

ALK A343
10th May 2009, 06:00
Flyman35 used one of the oldest tricks known to aviators. It is called airmanship. What is wrong with thinking outside the box? In my opinion we need more pilots like that in this day and age.
Sometimes normal line-pilots end up unknowingly being test-pilots.
Few examples are the United DC-10 guys in Sioux city, DHL A300 in Baghdad and British Airways 747 over Jakarta, though you can hardly compare those with a little Pack 2 fault.
I would like to know how the Virgin A340 partial gear extension landing in LHR would have ended if the crew had not used proper airmanship and altered the procedure to suit them? What was the Airbus reply to it? Well they amended the QRH. Well done boys.
Also why have pilots in the first place, if we are not supposed to use our brains. Airbus and the airlines could save a lot of money and have the ECAM checklist execute itself without pilot input.
Please think outside the box gentlemen!

Flyman35
10th May 2009, 19:30
guiones Shutting down a pack if ECAM or procedure does not call for it leaves you exposed to a lot of problems; legal and technical. All for temperature control!!!


Thanks for binging that into my attention and I appreciate if you point out any legal reference in ICAO,FAA or JAR regulations or even Airbus Industries, Boeing Manuals, or Douglas, or any MEL that states the prohibition of flying with one pack with the any related type of aircraft, except for altitude restrictions. so I think I hadn’t breached the law, jeopardize the passengers nor violated any procedures rather than thinking outside the box in an attempt to prevent the passengers from spending 5 and half hours in 18 degrees Celsius .however I like your idea about getting further information from the manufacturer and I will email them and see.

toby320
11th May 2009, 04:22
if we follow the procedures and at the end we don't get what we want and we think out side of the box and found something with no risk and solve a problem...bravo that's what a pilot have to do is our job if we only follow procedures we become robots, so just think about it. :D

pensador
11th May 2009, 08:24
Flyman35. You are very lucky pilot. You lost PACK 1 on the ground shortly before the flight and the failure could be linked to your previous manipulating with the PACK 2. Let's assume that you lost PACK1 in cruise. So, as minimum you will have "cold" flight (you will fill it first) and you will be forced to make much more brain storm and on transit stop you have to solve problem with PACKs. The question is why wasn't it done during first transit stop? Nothing can be minor on this a/c.
I am positive about being open minded, do a brain storming but don't forget about flight safty (you are not alone in the a/c).
Waiting impatiently for the Airbus reply on the guiones' post.

aulglarse
12th May 2009, 10:06
I have had a similar experience where we turned off Pack2 as ACSC #1 controls Pack 1 and the Hot Air valve, therefore a good chance of eliminating the threat.

Dom Joly
12th May 2009, 12:19
Flyman35

Thanks for your post, as mentioned, thinking outside the box.

Naturally, when it comes to CRM, I often consider what will happen should we lose the remaining system, however in this case if you lost Pack 1 in flight, potentially you could reinstate Pack 2, so no big issue.

Can I ask whether you looked at the MEL though? I appreciate that the aircraft is in flight, therefore not legally pertinent but still has some useful tips. In our MEL with one pack inop/switched off I would refer to 21-52-01 which has a limiting altitude of 31,500'. Therefore this would have meant a descent to FL 300 (if available). On top of this, there would be the additional fuel burn (roughly 5% per 4000') to consider.

After considering our fuel state, delays, wx @destination & alternate, I would have then considered descending.

I have to admit that I am not totally sure what the 31,500' relates to, I would presume that it may be to do with sufficient air pressure in the fuel tanks? However, just to play safe I would have complied with the MEL, after all it must be in there for some reason!

396.8T
12th May 2009, 12:34
Dom,There is no FL restriction,once airborne,with single pack operation on the A320.IF your MEL states this its different to most 320 operators.

Dom Joly
12th May 2009, 13:53
The 31,500' applies to my current airline and my last airline. Could this be a UK restriction, I appreciate that airlines are able to make further restrictions on the original MMEL but for two airlines to do it, makes me think that there may well be a reason for it. A copy of the exact wording is below:

a) Except for ER operations, one may be
inoperative provided:
1) Flight altitude is limited to 31,500
ft (9,600 m), and
2) COND ZONE REGUL FAULT
caution is not displayed on ECAM
E/WD, and
3) Affected PACK 1(2) pb sw is
selected OFF, and
4) Affected pack flow control valve is
checked closed on ECAM BLEED
page.
Note: Above condition 4) does not
apply if pack valve has been
secured closed as per item 21–51–
01.

Naturally, I know that the MEL is not limiting when airborne but I would adhere to it's guidance, especially in the circumstances where you are doing something non-standard.

Is this 31,500' in any other airlines MEL? Seems strange why it is as exact as to the 500' when other airlines don't have it at all in their MELs.

396.8T
12th May 2009, 14:50
Have a look at http://www.pprune.org/tech-log/365740-single-pack-ops-a320.html where its been discussed previously.Ive had to shut down a pack very early into a 5 hrs 30 sector where I could have continued below FL 315 where a tech stop was probable.We elected to continue at higher levels with single pack ops but after landing the CIDS started to give some problems due to the fact we had 180 pax on board and a lot of condensation had built up behind them!!

Thunderbug
12th May 2009, 17:27
Dom

Until about a year ago we had the 31,500 alt restriction for dispatch with a single pack.

Now the company (major UK Airbus operator) have changed to what is pretty much a direct copy of the Airbus MEL. This gives us the options of no altitude restriction provided the speedbrakes work. If your speedbrakes are U/S and you have a single pack then 31,500' is your max.

You have to check the MEL very carefully especially with respect to MSN number as some aircraft are restricted to 37,000 on a single pack even with the speedbrake working.

T'Bug :ok:

ALK A343
13th May 2009, 04:17
Agree with T'bug,
It is very important to get the MSN right, especially for operators who fly both the really old A320s as well as the latest ones.
When we had the older models I remember having the 31500' limit without speedbrakes.
The company took a very practical approach and limited all aircraft to 31500' irrespective of MSN if single pack operations were planned, giving us extra fuel on the flightplan.