How close was I to dying? (serious question)

[kuhne]

First of all let me say I tried other places in the net, one of them being Yahoo answers and it was absolutely no help, which led me to look for serious, smart people who are related to actual airliners and flying in general, so I came to this forum, made an account and here I am.

A small introduction, I am a guy who doesnt fly often, I average 12 flights a year I would say and they are all pleasure related. I am no pilot or have anything to do with the airline industry but in the past me and my family were involved in the business enough time for me to gain respect and admiration.

I was never (and still am not) an easy flyer, I love airplanes and airports and traveling but once I am inside the airplane, every single unusual noise or unusual bump makes me nervous, even though deep inside I know all the facts of why such things happen.

So here I am, yesterday, my wife and me took a flight to cancun in a Mexican airline called Interjet, this airline prides itself in having good prices, new airplanes, top of the line service and great comfortable seats. I have flown with them 4 times in the past and I allways loved it.... but then came yesterday.

We got into the plane, a A320, very, very new looking, very clean and we took off.. nothing out of the ordinary until the flight attendant calls for a medic... apparently a lady was feeling sick (or scared, I dont know) and the pilot had to return to the airport and land. Medical personel went into the plane and took the lady and her family member off the plane, they refueled the plane, and off we went.... second try to go to cancun..

Before I continue, there is this sound airplanes make, usualy before they even move away from the terminal, it allways sounds as if the pilot is testing something, I think it is the spoilers moving or something, the sound is like a screeching horrible sound that goes like "Wwwweeeeeehhhhhooooouuu! wwwweeeeeeeeehhhhooouuu!!"

Ok, now that I have told you about that sound, ln, let me continue my story.

We take off again, great take off, no turbulence, everything seems fine, I am sitting right beside the left wing in the exit row, window seat, so I can see the flaps and spoilers (or whatever they are) are still in position, I am just looking, waiting for the pilot to revert them back.. the moment they go back, that screeching sound I talked about before sounded for about 4 seconds and then stoped and right after the sound stoped I could a kind of leak... something bubling or something.... not a good sound to hear inside an airplane.. after that the "wweeeehhhh" sound came again and stoped, followed by the same bubling sound.. and this went on for about 20 times... as if the pilot was trying to make something work but it just wasnt working... then it just stoped.. but the bubbling sound seemed to continue and we flew for about 20 minutes but I noticed we werent climbing.. then I noticed we were turning around.. and then the flight attendant says that we are going back to the airport (AGAIN) because of that sound that we heard a while back.. its not a normal thing that should happen and for security reasons we are going back.

So of course we all went silent.. the whole plane.. then after a few minutes the pilot says this.

"This airplane has 3 hydraulic systems, one of them has failed, the second one has overheated and the third one is working properly, we have attempted to cool down the overheated one and have succeeded and will be using that one to land the plane, which means we will have landed with two fully working hydraulic systems and one failed. This is an emergency but a perfectly doable manuever"

He sounded calm and I know enough to know that we would probably be ok.

The thing is, once we got over the airport, the pilot kept doing circles around the airport and wasnt landing, I know for a fact there was no trafic and as far as I know, dumping fuel is only a procedure you do when there's an engine problem and as far as I know fuel dumping would have taken way longer. But the pilot didnt say a thing, he just kept circling the airport and I was worried then, thoughts of past crashes started filling my head of how hydraulic systems fail and the pilot has no control over the aircraft, I started to think he wasnt able to lower the plane.. simply not able to land.

After about 20 minutes of this, we eventualy heard the landing gear come out (best sound i've ever heard in my life) and we landed safely, the pilot instantly shut the engines off and the emergency crew outside came to check the plain and they confirmed to the pilot what had happened, and the pilot instantly confirmed it to us, he said "as expected, a hydraulic hose was broken"

Then we were towed to the terminal, they changed us to another A320 right beside the one we were in and we took off to Cancun in that one, which I am happy to say, other than horrible turbulence during take off, it was a very, very pleasant flight and right now I am writing this from cancun, very relieved.

Now, after all that story you people are still here and not bored, here are my questions.

First, the not very important question but still looming over my head.. WHAT ARE THE #^$@^$ ODDS OF THIS HAPPENING TO ME! god damn! first the lady feels sick and we return then we take off again and a hydraulic hose breaks? I felt that flight was cursed!

Ok, now for the important questions.

1. How common is this type of problem? I know it's relatively common to have Hydraulic problems in airplanes but what about this specific type of problem?

2. How close were we to actually dying? Honestly, I know A320 planes (and planes newer than the 737) dont have manual controls, they have 3 hydraulic systems and if those 3 were to fail you are basicaly screwed. Sure you can do some maverick stuff with engine thrust and what not but more than likely you are screwed. I know many people will say "Well, thats why you have 3 hydraulic systems, to make sure that never happens" And you would be right.. except the pilot said 1 system failed and the other overheated which means for a while we were relying only in one of them (before the other one cooled i guess) so if two fail like that..... why not 3?

3. Was the woman feeling sick a lucky thing? I am thinking if the lady doesnt feel sick we would have been in the middle of the sea on our way to cancun when the problem would have surfaced.... OR maybe it wouldnt have surfaced at all? Maybe it would have been in the landing or maybe the next passengers on that flight?

4. Why do you think the pilot did so many turns around the aiport before landing? I know it was not trafic and apparently ty the plane was working fine, was he trying to cool down the system a bit more? I dont think he was dumping fuel, that would have taken quite a while longer and we didnt have any type of engine trouble.

Basicaly thats it, I know we dodged a bullet, I just want to know what type of bullet it was, for a while there I was really afraid.. specialy when the pilot kept circling the airport without saying anything. I was expecting a message from the pilot at any moment saying "we're having trouble, we can't land, etc..." I just grabbed my wife's hand and well... you know....started thinking about not very pleasant stuff. There were some "funny types" in the plane that laughed every time there was a turbulence bump and were making fun of everything and even then, when the weird sound came on, they just went silent.

To be honest it was kind of hillarious when we were in the second plane right about to take off and the pilot moves the spoiler and makes the "Wwwweeeeooeoooo" sound again, one of those guys went "Hey wait, this one has the same symptoms as the other!" Me and my wife just had to laugh at that... I am just glad I am here to talk about it.

Alright, thats a big story, sory to bore you, just had to get it off my chest. Please, I beg you, if you know about aircrafts enough to answer my questions, please do so.. the kind of replies I get from Yahoo answers range from "Oh yeah, many times theres accidents due to hydraulics"

to

yeah, thats how "xxx" plane crashed

then the next post is another guy saying "no foo, "xxx" plane crashed because of something else.

You get what I mean.

[flame_bringer]

I reckon it was very wrong and stupid of the pilot to provide the passengers with extra details over the current on going snags on the PA and freaking them out.
He could of just informed you that there is a technical issue and due to it you're expected to go though an emergency landing for safety reasons but to tell the passengers of how many hydraulic systems have failed and one has overheated, freaking them out and things as such is just rather unprofessional, This pilot should be kicked out of the airline.

Circuling around the airport was probably a procedural turn or perhaps he was asked to do that by the ATC controller untill the runway is cleared for him to land.
The screeching sound was probably the slats&flaps retraction.
Let's see what the experienced folks around pprune think.

[Gentle Climb]

Firstly, I don't fly the Airbus, but in general...
1. Failures occur sometimes. Dual failures of the same system occur less frequently.
2. I don't think that you were even remotely close to dying. The situation was dealt with by the crew no doubt in accordance with SOP's.
3. I can't think that the sick passenger made too much difference. The problem could have evolved at any time during the flight and diversions would be available.
4. There are any number of reasons for the circling. Maybe getting all of the checks done accordingly, maybe wating to burn off some fuel, waiting for the airfield to be ready. The crew were just doing the right thing. The biggest clue to the lack of emergency would seem to be the ordered manner in which the situation was dealt with. A significant problem would have had your aircraft inbound to land very quickly. I wouldnt worry about it. You were merely inconvenienced.

As for the subsequent post...I would think that the passengers would be relieved that the flight crew knew exactly what the issue was and how it was going to be dealt with. A general 'technical problem' statement from the flight crew may lead passengers to think the worst. Disagree with most of your comment I'm afraid.

[WillDAQ]

I know we dodged a bullet

You didn't, there was no bullet.

1. Hydraulic system failure.
2. Isolate fault
3. Return to airport, burn off fuel until maximum landing weight is reached
4. Land.

While not a common fault, it is something that all of the crew are trained for. Your 'chance of death' was increased from "phenomenally unlikely" to "exceedingly unlikely" while they isolated the fault. After that it's service as usual.

Man up.

[Genghis the Engineer]

Originally Posted by WillDAQ

You didn't, there was no bullet.

1. Hydraulic system failure.
2. Isolate fault
3. Return to airport, burn off fuel until maximum landing weight is reached
4. Land.

While not a common fault, it is something that all of the crew are trained for. Your 'chance of death' was increased from "phenomenally unlikely" to "exceedingly unlikely" while they isolated the fault. After that it's service as usual.

Man up.

Pretty much - the aeroplane is fully controllable on any one of the three hydraulic systems, possibly with loss of a few facilities, but nothing critical.

In the event of failure of all three hydraulic systems, the aeroplane remains controllable - albeit with rather more difficulty.

Burning off fuel is a common and legitimate action; much slower than dumping but upsets the locals less and gives the airport time to prepare in case the emergency does escalate.

An interesting point about how much the captain chose to tell the passengers. Personally I think he was right to be open with them, but many experienced pilots would feel otherwise.

G

[vs69]

I wouldn't say you were particularly lucky to survive or unlucky to be on that flight, things on aeroplanes fail from time to time hence the built in redundancy in systems.
A few points from your post:
There is no fuel dump facility on A320 a/c so land overweight if in a hurry or if you have the time fly around and burn some off.
The noise you heard (which some people often think is a dog barking) is the PTU, it is a hydraulic motor that can transfer hydraulic pressure (not fluid) between 2 of the hyd systems on the aircraft. If the logic in the system detects a pressure drop on one of the systems (Green or yellow for you spotters out there) the PTU operates and maintains system pressure. Operating a heavy user fed by that system is enough to enable this IE flaps.

[ChrisJ800]

The "Wwwweeeeeehhhhhooooouuu! wwwweeeeeeeeehhhhooouuu!!" sound you describe is probably the PTU or power transfer unit which is really noisy on A320's but entirely normal especially on engine startup when it needs to pump hydraulics to the other side. You should be more worried about the car or taxi drive to or from the airport!

[mono]

Even with one hydraulic system you have more chance of dying or being injured crossing the road

[cod liver oil]

Why are you banging your head against a wall mono?

It seems that our friend kuhne does not have the same knowledge and insight into the world of aviation that you might benefit from. He has taken the time to post a reasonable query in order to solicit opinions on this site. I imagine he just wants to put his mind at ease for future travels.

Not so sure I understand the reason for your level of frustration.

rgds cod

[Alber Ratman]

The A320 has 3 hydraulic systems, Yellow circuit, Green circuit and Blue. Yellow and Green systems are pressurised in normal use by the engine driven pumps (that are bolted to the accessory gearbox of each engine). If these pumps fail, the circuit does have electric motor driven pumps that while not being able to produce a flow rate as high as the engine driven ones, produce enough pressure and flow to operate controls as quickly as if fluid was supplied by the EDP. Flap/slat and undercarriage opperation rates would be reduced due to reduced flow rate, but that would be the only a few seconds at most. One system can drive generate pressure and flow into the other (and vice versa) by your noisy PTU. If both the Green and Yellow systems fail, There is always the Blue system that operates all control surfaces via seperate servo actuators to the flying controls and if that circuits electrical pump fails, there is still the Ram Air Turbine (RAT) hydraulic pump avaiable to pressurise it. If all electrics fail, the flight crew still have some control available via mechanical link to the horizionatal stab actuator (THSA) and the Rudder.. Some old Fly by Wire, but not really one that should be wished to be used by any crew..

BTW you have more chance of dying walking out of your house (being in Mexico) than you did in this aircraft incident (that it is, because some system failed when it should not have..)

[tom775257]

It is a problem on the A320 that as pilots we are told about. For example, you take off, you lose pressure in the yellow hydraulic sytem, the power transfer unit (in this case driven by the green system) attempts to pressurise the yellow system. If the yellow system was lost due to loss of fluid and not a simple pump failure the PTU will be attempting the impossible and if you are not fairly quick to turn off the PTU on the overhead panel you can overheat the other system that is driving it.

During takeoff you will have many things to do and in the drills it takes a while to get to turning off the PTU so hence this can cause overheat. We were issued an aircrew notice reminding us to kill the PTU if we have a loss of fluid.

Either way the aircraft is fine to fly on one hydraulic system, just not ideal.

[kuhne]

You guys have been really helpful, this made me and my wife feel better about the situation we were in, I guess the crazy thing about it is how we took off two times and both times we had to return fro two different situations. Thats just bad luck.

It's nice to see many of you helped me with technical specs, its nice to know that even though its not normal, it's something that happens and I was perfectly fine in that flight.

I do find it interesting how one person flat out siad thats why he never flies an Airbus, Ironicaly, the last crash I remember happening due to complete hydraulic loss was a 747.. wasnt it?

[kuhne]

Tom, what you are saying is that the second hydraulic system was trying to "fix" the first hydraulic system that failed.. but because the first system failed in a way that was unfixable (broken hose) then it just kept trying and trying and trying and thats why it got overheated? Was this the sound we kept hearing over and over?

If worst came to worst and both systems would have died... does the third system act completly independent to these two and would we have been fine with that third one?

[kuhne]

I wrote a post before thanking all of you for trying to help me and told you all your comments helped me and my wife in ways you cant imagine.

But for some reason the post didnt show up.. maybe it was deleted?

[Blacksheep]

"Sniff! Sniff!! Hmm, smells like a journo." Cocks leg on post and trots off looking for a bone....

[tom775257]

<<Tom, what you are saying is that the second hydraulic system was trying to "fix" the first hydraulic system that failed.. but because the first system failed in a way that was unfixable (broken hose) then it just kept trying and trying and trying and thats why it got overheated? Was this the sound we kept hearing over and over?>>

Yes and it would keep on trying until you turned off the power transfer unit (PTU). This automatic feature is very nice in many circumstances eg engine failure. Because the main hydraulic pump on both yellow and green are engine driven, if you have an engine die, the PTU automatically kicks in to replace the lost engine driven pump... therefore you don't have to deal with an engine failure and combined hydraulic failure. The automatic function of the PTU is annoying when you have a fluid loss in one system.

<<If worst came to worst and both systems would have died... does the third system act completly independent to these two and would we have been fine with that third one? >>

Yes, the blue is indeed independent and the aircraft can happily fly with only one remaining hydraulic system.

That said you should be able to recover the overheated system after turning it off for a while and you would be back to two hydraulic systems as happened in your case.

[truthinbeer]

I sometimes wish I was a CPL just so I could switch on the intercom and say to the passengers, "Ladies and gentlemen, I just wish to say that there is absolutely no cause for alarm."

And then I would switch the intercom off.

[Matt101]

May or may not find interesting.

A very simple (pilot friendly) overview of the A320 Hydraulic system. It may just help you to see how much redundancy is built into the thing and how not worried you should be. The general idea put forwards by other posters sounds about right though I'd caution anyone to make any assumptions based on what they heard. However the one Hyd fail PTU overheats other system sounds about right.

A320 Hydraulic System Overview (Sorry I'd embed the image but it is huge and I have no idea how to scale it down on PPRuNe)

I'd also add the holding may have been to burn fuel off to escape having to perform an overweight landing, given that on 2 HYD systems the urgency to land is removed.

[FlyingEagle21]

more of a chance choking on you in-flight snack.

[FlyingEagle21]

more of a chance choking on you in-flight snack.

Like this guy..

Man chokes to death on an in-flight meal | Mail Online