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Jet Blue A320 loses two hydraulic systems

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Jet Blue A320 loses two hydraulic systems

Old 21st Jun 2012, 11:30
  #61 (permalink)  
 
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Known fault that if GREEN or YELLOW loses pressure due to fluid loss then the PTU starts BUT if there is only fluid on one one side then the PTU burns out causing the other system to leak out through the burned hole!!!

Our Company SOP is the to turn off the PTU without delay following the 'low pressure' of GREEN or YELLOW system. I think Airbus are working on a fix that this will happen automatically allowing the crew to make the decision about turning the PTU back on?

10 says that this crew left the PTU running.
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Old 21st Jun 2012, 11:35
  #62 (permalink)  
 
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Quite sure in a single failure ECAM alls for PTU off...
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Old 21st Jun 2012, 12:12
  #63 (permalink)  
 
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I think (although stand to be corrected) it depends on FWC standard?
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Old 21st Jun 2012, 12:23
  #64 (permalink)  

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PTU is used after single engine failure or hydraulic pump failure. It must be switched off quickly with lo pressure, lo level, or overheat of either the green or yellow system. Otherwise one will end up with a dual hyd system failure.

Some have made reference to the 330 in their comments. Not the same. Different hydraulic system, no PTU.

Insufficient info here to draw conclusions.
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Old 21st Jun 2012, 13:16
  #65 (permalink)  
 
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i'm not a pilot but dumping fuel is a customer option ??
i would have thought this was mandatory
Well, dumping fuel is basically a crew option.

To have a fuel dump system installed or not...., look to previous posts.
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Old 21st Jun 2012, 13:28
  #66 (permalink)  
 
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Deggers,

On A320, fuel dumping is not an option, it's plainly NOT available (unless you can pay A LOT of money to get a customized one )

Locked Door, could you elaborate how the A320 is still flyable after a triple hydraulic loss? I haven't found anything in my books...

The A320 needs always at least one source of hydraulics to control the (remaining) flight surfaces. Lose all of them and your remaining flight time will be rather short.

The equivalent of a manual reversion on the A320 series is simply not called a manual reversion because there is nothing manual about it. It only means the flight computers are not able to compute and actuate surface movements with the degraded systems. Rudder will steer with pedals via cables to the tail (need at least one hydraulic system), and the pitch trim is called "manual pitch trim/only" as opposed to autotrim normally provided. The pilot moves the trim wheel, which turns a bicycle chain and actuates valves in the hydraulic block in the tail...so you still need the hydraulics.
Without the autotrim, the FBW is uncomfortable to hand-fly due to the neutral on the joystick not matching balanced elevator, so for example to fly straight and level in this case will require a constant push/pull pressure on the stick, making it sensitive to departure from steady conditions.
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Old 21st Jun 2012, 13:57
  #67 (permalink)  
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Not with regard to this incident, about which I know very little, but on the general subject of fuel dumping/overweight landings--

There appears to be a very strong bias in the United State/FAA land against overweight landings. It is generally not trained, or even discussed in training (in my experiance), while fuel dumping is in almost every checkride in airplanes so equipped.

This is a problem, to put it mildly.
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Old 21st Jun 2012, 14:12
  #68 (permalink)  
 
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A year or so ago a poster noted that a good percentage of (those who claim to be?) Airbus pilots appeared not to have a sound grasp of systems knowledge.

If no other thread has demonstrated the point, this one surely has.
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Old 21st Jun 2012, 14:21
  #69 (permalink)  
 
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Possibly because Airbus produce the worst suite of manuals I have ever seen in four jet endorsements.
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Old 21st Jun 2012, 14:32
  #70 (permalink)  
 
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KUDOS TO JOCKSTER for giving us a very plausible scenario.

It might add to his case that a cable news show said: the plane had to be towed off the runway as ITS NOSEWHEEL STEERING DIDN'T WORK.

This implies, or allows me to infer, that they landed on the blue system.

that PTU seems like a weak link...and don't even get me started about the other weaknesses in the 'bus.

and in my free time in the sim...the thing I would practice is flying the thing on thrust changes, both symmetric and assymetric...just in case

and boys...if you are out west...head for EDWARDS dry lake.
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Old 21st Jun 2012, 14:39
  #71 (permalink)  
 
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and again...about FUEL DUMP...most planes don't have it and don't need it by regulation. offhand I would say that the 747, 777, 787 have it....some, not all 767 have it.

the DC8 had it, and Air Canada bought DC9's with it...though no one else has it on the DC9 and it was turned off later on the ones equipped with it.

Boeing even put out a chart that I have, but can't upload, of Boeing planes that did have fuel dump.

I think the L1011 and DC10 had it too.

There are some cases which for PERFORMANCE issues require the ability to dump fuel...and this performance is for engine(s) out go arounds. And while bubbers and others are right, you can GENERALLY come back to the runways you just took off from, there are specific situations , mainly with extremely long range planes loaded with huge amounts of fuel, that require dumping.

fuel dumping (while helpful) is not SOLELY for protecting the structure of the plane on landing.
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Old 21st Jun 2012, 14:44
  #72 (permalink)  
 
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flying ANY underwing engined airplane without hydraulics:

1. add power on both, nose goes up, plane goes up (within limits)

2. reduce power on both, nose goes down, plane goes down.

3. add power on right engine, reduce power on left engine , plane skids around to left, poorly...perhaps losing altitude, perhaps gaining.

4. add power on left engine, reduce power on right engine, plane skids around to right, poorly, perhaps losing altitude perhaps gaining.

one could with God's good graces manage a marginal landing...see Sioux city DC10 accident.

A computer program to manipulate thrust was developed for the air force (USAF) to show how a battle damaged plane could be landed...using thrust only.
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Old 21st Jun 2012, 15:08
  #73 (permalink)  
 
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Gents:
Mechanical back-up is rudder and trim - both need hydraulic pressure to work, so a triple hydraulic failure leaves you with NO flying controls. You have engine thrust, gear extension and passengers running forward and rearward for control ... mechanical back-up is designed to provide a minimum of control following a complete loss of electrical power (side sticks don't work!) ...before you can get the RAT deployed, and the emergency generator up to speed.)

Mechanical Backup on the Airbus is not a redundancy against hydraulic loss. It's to be used "during temporary loss of aircraft electrics" whilst the backup gen comes online (from the Airbus FCOM) and requires at least one functioning hydraulic system.
As has been said above, total loss of hydraulics on the Airbus results in loss of all flight controls.

Locked Door, could you elaborate how the A320 is still flyable after a triple hydraulic loss? I haven't found anything in my books ... A320 needs always at least one source of hydraulics to control the (remaining) flight surfaces. Lose all of them and your remaining flight time will be rather short.
Grateful for the clarification, and FWIW, this appears to match my outdated A330 systems diagrams and systems explanation. The further commentary on fuel dumping, or its absence, is also appreciated in terms of adding to understanding. (I realize this is an A320, but the similarity in design philosophy does not surprise).

Likewise, grateful for the commentary on reasons to, or not to, remain airborne while trying to recover use of one of the two hydraulic systems that had shut down. For all the bickering, there is some very good stuff in this thread.

Last edited by Lonewolf_50; 21st Jun 2012 at 15:09.
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Old 21st Jun 2012, 15:30
  #74 (permalink)  
 
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742:

There appears to be a very strong bias in the United State/FAA land against overweight landings. It is generally not trained, or even discussed in training (in my experiance), while fuel dumping is in almost every checkride in airplanes so equipped.
Almost every bird I flew had fuel dumping. So, we had to go through the dumping drill in the simulator because it was a proficiency requirement that came with those types.

We didn't do overweight landings in the sim because it would have served no useful purpose.

But, starting after the first embargo in 1973, the company made it quite clear that landing overweight was the preferred course of action over dumping except perhaps with an engine failure or a missed approach OEI climb gradient issue.

From that time most crews at my company landed overweight as opposed to dumping fuel and no one ever heard from the FAA. In fact overweight landings had tacit FAA approval.
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Old 21st Jun 2012, 15:37
  #75 (permalink)  
 
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I trust these overweight landings were not a regular occurence though? Would have put the MX costs up with all those extra inspections??
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Old 21st Jun 2012, 16:17
  #76 (permalink)  
 
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There has been a recent case of an A319 crew not being able to switch the PTU off due to a faulty PTU switch... Therefore a single hydraulics low level activated the PTU which has overheated and taken out the second hydraulic system...

Incident: Air Canada A319 near Winnipeg on May 30th 2012, two hydraulic systems failed after leak
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Old 21st Jun 2012, 17:01
  #77 (permalink)  
 
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Not with regard to this incident, about which I know very little, but on the general subject of fuel dumping/overweight landings--

There appears to be a very strong bias in the United State/FAA land against overweight landings. It is generally not trained, or even discussed in training (in my experiance), while fuel dumping is in almost every checkride in airplanes so equipped.

This is a problem, to put it mildly.
Almost every bird I flew had fuel dumping. So, we had to go through the dumping drill in the simulator because it was a proficiency requirement that came with those types.

We didn't do overweight landings in the sim because it would have served no useful purpose.
Errrr, right... I'm curious, what did they expect you to do in the sim (i.e. in real life) during a engine/cargo/cabin fire that could not be contained? Spend 40-50 minutes dumping fuel?

With regards to airmanship and system knowledge this thread is an absolute shocker. United 232 at Sioux City? Swissair 111 near Halifax? Any lessons learned?
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Old 21st Jun 2012, 18:33
  #78 (permalink)  
 
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Bokkenrijder: 
errrr, right... I'm curious, what did they expect you to do in the sim (i.e. in real life) during a engine/cargo/cabin fire that could not be contained? Spend 40-50 minutes dumping fuel?

As I said in my previous post, overweight landings were the real world preference. Sim, in my book, is not "i.e. in real life." Never burned up a simulator yet.

Last edited by aterpster; 21st Jun 2012 at 18:35.
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Old 21st Jun 2012, 18:40
  #79 (permalink)  
 
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@ aterpster

But, starting after the first embargo in 1973, the company made it quite clear that landing overweight was the preferred course of action over dumping except perhaps with an engine failure or a missed approach OEI climb gradient issue.
As I said in my previous post, overweight landings were the real world preference. Sim, in my book, is not "i.e. in real life." Never burned up a simulator yet.
Again, two very strange statements;

1) With the 1973 embargo, I assume you are referring to the 1973 oil embargo? Why would any pilot let commercial considerations take priority during a severe technical failure? The whole point of overweight landings is to save time, not fuel!

2) Why would you treat a sim session any different than a real life scenario? Isn't the the whole purpose of sim training and checking to simulate real world scenarios?

Last edited by Bokkenrijder; 21st Jun 2012 at 18:43.
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Old 21st Jun 2012, 19:15
  #80 (permalink)  
 
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My major airline in the US advised not dumping fuel if the landing was just as safe landing over weight. I wondered how this would sound at the hearing so decided overweight landing couldn't be as safe as landing at Max landing weight so ignored their advice knowing it was put out by the management people. A few months later I got a 727 with a radar problem written off as re racked ok for service. I told the FO we have a bad radar and we need it for this flight through a tropical storm to south America so expect it to quit since they didn't fix it.

We hit a bump on the runway at rotation and the radar quit but we knew where the close in weather was so requested a straight out departure. Circuit breakers , pounding on scope and normal pilot techniques didn't work so we went off shore and dumped fuel to max landing weight and came back to MIA. Never heard a word about why didn't we land over max landing weight and no hearing. I think the hearing is when you follow their advice and land overweight and have to explain why.
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