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Merged: Oxygen tanks topped up with Nitrogen

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Merged: Oxygen tanks topped up with Nitrogen

Old 17th Dec 2007, 02:02
  #21 (permalink)  
 
Join Date: Mar 2007
Location: Australia
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Oxy cart bottles are black.

Nitrogen cart bottles are grey

I have an idea. How about QF paint the whole oxy cart green? (aircraft bottles being green).

Oops... lean smegma mite steal that idea off me and someone may use it to get their purple belt.
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Old 17th Dec 2007, 04:30
  #22 (permalink)  
 
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So who were the 'industry professionals' who scoped out and oversighted the design of the new carts .......? did they consider 'human factors' issues ie. the new nitro carts should be clearly distinguishable from the new oxy carts... what about risk assessments and training on the new equipment... did a breakdown of 'due process' cause this..??
sharman, the answer to your question is so blindingly obvious I'm surprised you didn't answer it yourself.

Readers just need a translation to modern day aviation-speak.

- "industry professionals" = beancounters
- "due process" = cheapest quote
- "risk management/assessment" = cheapest option/procedure

There... it's simple when you speak the language, isn't it?


***

Since the mistake was found before the proverbial hole in Dr Reason's last slice of cheese lined up with some hapless crew suffering an decompression or a cabin fire, I suppose we should be grateful that the original mistake was getting a nitrogen cart confused with an oxygen cart and not the other way around. Had it been the other way around, there could have been a major explosion had some unfortunate LAME tried working on the cart with a greasy spanner - or, as someone has mentioned already, if someone had tried using oxygen to fill an undercarriage oleo.
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Old 17th Dec 2007, 18:20
  #23 (permalink)  
 
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if someone had tried using oxygen to fill an undercarriage oleo.
That thought makes my hair stand on end. How does an exploding oleo on full compression on touch down sound?

As for "Nitrogen Narcosis", nope, you would need to be breathing normal strength air in an atmospheric pressure of about 60PSI to get whoopsy.
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Old 17th Dec 2007, 20:22
  #24 (permalink)  
 
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Having worked in the medical area in a past life, this sort of thing would not have happened if they took the lessons learnt from medicine. A long time ago, Doctors discovered that if you fill a patient up with the incorrect gas, the results were not conducive for a long life. Following some investigation they came up with the idea that if you make each gas fitting unique, then the possibility of placing the wrong gas in the wrong area was removed from the equation. As a result, oxygen cylinders can not be connected to CO2 cylinders because the collar is different. It is the same with nitrogen and the other gases found in hospitals. Anaesthetic gases work along a similar line when added to the anaesthetic machine.
The question I ask is "How difficult would it be to have unique fittings for each gas cylinder?" I know of nitrogen and oxygen being used in an aircraft, but are they any other ones? Maybe the gingerbeers out there can help.
Tinkicker
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Old 17th Dec 2007, 20:38
  #25 (permalink)  
 
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Wrong Gas leads to thread creep.

Good one for the Mythbusters.

Will an oleo disintegrate if some idiot tries to pressurize it with oxygen?

And what are the consequences of filling a tyre with oxygen?

And how about the fuel cells that are nitrogen purged?

Some interesting stories may be about to come to light.

Murphy's Law says it will happen!
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Old 18th Dec 2007, 00:09
  #26 (permalink)  
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Can this be for real???

NITROGEN USED TO FILL AIRCRAFT OXYGEN SYSTEMS
Airlines all over the world are being warned to check to make sure thereís actually oxygen in their aircraft oxygen systems after an embarrassing mix-up by Qantas Airlines at Melbourne International Airport. For ten months, crews have been filling airliner oxygen systems from a nitrogen cart thatís supposed to be used to fill tires. The mistake went unnoticed until a couple of weeks ago when an observant aircraft engineer spotted service workers using the cart. "He was walking around the plane and asked what they were doing. When they said they were topping up the oxygen, he said, 'No you're not, that's a nitrogen cart,'" an unnamed source told The Age. As anyone who works with industrial gases knows, oxygen tanks have different fittings than other gases to prevent exactly this kind of mix-up. However, when the crews discovered the fittings on what they thought was their new oxygen cart didnít fit, they swapped them for the ones on the old cart they were retiring. Of course, Australian officials are looking into the error and Qantas has been busy notifying other airlines that use its services in Melbourne. Hundreds of aircraft may be affected.
 
Old 18th Dec 2007, 01:09
  #27 (permalink)  
 
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The carts were designed by LAME's, for LAME's and IAW the relevant standards, i.e. colour coding etc.
Extensive consultation was carried out across the network with involvement of both trades.
No they weren't the cheapest or easiest option. They took a hell of a lot of frigging around to get right.
The cheapest and easiest would have been an off the shelf product which didn't meet our requirements so far as ease of use, safety and maintenance.
The carts are coloured coded differently.
The bottles are still grey for nitro, black for oxy.
The fittings are still different between carts.
The only possible deficiency may have been in the implementation and training stage in Mel, but that is purely speculation.

I hate to say it, but it could have just been a monumental brain explosion.
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Old 18th Dec 2007, 01:28
  #28 (permalink)  
 
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The difference between grubby scratched grey or black cylinders at night, when raining, in blinding sun, under time constraints with a good level of fatigue etc, etc, etcÖ. Itís gunna happen.

As stated before, why not paint the cylinders green or the carts green (even easier), it will now be obvious at a great distance to all.


Talk to CASA & BOC, stop the holes in the cheese aligning now.
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Old 18th Dec 2007, 07:22
  #29 (permalink)  
 
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Some important points.

1)The fittings are different between oxy and nitrogen systems as stated several times already. SO TO ALL THOSE WHO KEEP SUGGESTING THIS, STOP IT. IT HAS BEEN MENTIONED HERE OVER AND OVER AND OVER.

2)Different coloured bottles... different shut off valve and regulator arrangements on the carts. If even basic training had been given, those involved should have known immediately that they were using the wrong cart.

3)Potentially fatal? Highly unlikely. An oxy system is never completely filled and therefore, there is no chance that the system would contain pure nitrogen or even a high percentage. If the system is showing empty, bottles are REPLACED with FULL bottles from stores. Those bottle would have been filled in the oxygen shop in component maintenance.

Normally, you would only have to add around 100-300PSI to the system. Off the top of my head, 1850PSI is the aprox. system pressure. 300PSI represents 16% of the total pressure.
The air we breathe is aprox. 78% nitrogen and 21% oxygen. In order for a potentially fatal level of nitrogen to be added, the aircrafts system pressure would have to have been considerably less than 380PSI!!!!!!!!!! If this were the case, It would indicate a major leak in the system and considerable troubleshooting would be carried out.

To say that this was a potentially fatal incident is just scare mongering. Far more potentially fatal would be filling a landing gear strut with oxygen due to the presence of oil and yes, this did happen im Melbourne once too.

Despite the scare mongering, those involved should be asked to sit down for tea and biscuits and to explain. I am guessing however, that the were probably not trained.
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Old 18th Dec 2007, 08:24
  #30 (permalink)  
 
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I am guessing however, that the were probably not trained
My thoughts exactly when I first heard about this.

If true, it more or less backs up Wiley's comments about "cheapest option". There was a time, before the beancounters took over damn near every facet of our jobs, where an untrained person would never have been in a position airside or in a maintenance hangar where he or she could have made such a decision (to switch the fittings).
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Old 18th Dec 2007, 08:48
  #31 (permalink)  
 
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Normally, you would only have to add around 100-300PSI to the system. Off the top of my head, 1850PSI is the aprox. system pressure. 300PSI represents 16% of the total pressure.
The air we breathe is aprox. 78% nitrogen and 21% oxygen. In order for a potentially fatal level of nitrogen to be added, the aircrafts system pressure would have to have been considerably less than 380PSI!!!!!!!!!!
This would be correct at sea level, but, at high altitude a much higher percentage of Oxy is required. If an explosive decompression happened at 40,000 feet, the regulator on each flight crews Oxy mask would give 100% Oxy in order the get sufficient partial pressure of Oxy into each pilot's lungs. If some of the gas being inhaled is not Oxy, then it's possible that the partial pressure of Oxy would be insufficient to remain concious. This error could have had very serious consequences if one of the affected aircraft had a decompression at very high altitude.
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Old 18th Dec 2007, 09:06
  #32 (permalink)  
 
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Hey NAS1801, You raise some very valid points. You must be a cone head..
You say someone in MEL has already filled a landing gear strut with oxy. I find that impossible to believe. Surely as soon as they opened the oxy tap, the fitting at the strut (wet with oil) would heat up, ignite the oil, turn into a flame thrower and destroy the strut/aero!????
Check this story from the United States Fire Administration..
The pressure regulatorís T-handled adjusting screw had become difficult to move. A maintenance employee used a popular hydrocarbon based lubrication spray on the screwís threads. The lubrication was done without the knowledge of the nursing or respiratory therapy staff who would have likely recognized the danger in applying a hydrocarbon lubricant. The next time the valve on the oxygen cylinder was opened, the heat of compression ignited the residual hydrocarbon contamination inside the regulator. The burning of the residual contamination was sufficient to start the internal parts of the pressure regulator and the brass body on fire. The health care worker who opened the oxygen cylinder was injured by the molten metal and blowtorch like flames.
Colouring the oxy cart green would be an idea. You cannot legally paint the bottles. They have to be black = international standards.
Magoo31 says
The only possible deficiency may have been in the implementation and training stage in Mel, but that is purely speculation.
Hmmm? Maybe look at who did the training at all the ports.
You also say
Extensive consultation was carried out across the network with involvement of both trades.
One has to ask "was there enough consultation". Possibly not! Sounds a bit like the ACS procedure for charging the small oxy bottles at the nitro cart. When they did their consultation, there was one BMS cone head oh&s guy on the team. As soon as he questioned their ideas, he got left out of the whole project. They didn't even talk to the oxy cave guys about the issues. Big mistake. Any cone head will tell you that procedure is a croc.
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Old 18th Dec 2007, 11:10
  #33 (permalink)  
 
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A similar error led to an engineer being supplied nitrogen during confined space work in a fuel tank at Ansett's Perth hangar some years ago.

On that occasion a (grey) nitrogen bottle was connected to the confined space breathing kit instead of a (grey) compressed air cylinder. Perth used the large compressed air bottles as their air compressor did not supply air of suitable quality for filtering to breathing standard.

Luckily, the engineer was up on a stand and only up in the tank to his waist.

When he became unconscious he fell limp to the hangar floor and was revived.

So, it can happen......

MP.
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Old 18th Dec 2007, 11:56
  #34 (permalink)  
 
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....and one of the findings of the subsequent investigation was that the fittings on the breathing air cart and the nitrogen cart were the same

saw that video some months back.
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Old 18th Dec 2007, 12:15
  #35 (permalink)  
 
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Correct, and not just the fittings, the neck of the bottles and thread sizes were the same on both the Nitrogen and the Compressed Air bottles.

And for the record, if he had been working alone he would be dead!

No radio or phone could have helped him.

MP.
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Old 18th Dec 2007, 18:30
  #36 (permalink)  
 
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The guys that did the risk assessment on the new carts arenít the A380 boys by chance? O.M.G.
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Old 19th Dec 2007, 03:30
  #37 (permalink)  
 
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The guys that did the risk assessment on the new carts arenít the A380 boys by chance?
Definitely not. One of the team that carried out the RA has been considered a loud mouth bully. Word is he kicked guys off the team when they disagreed with the way things were going. Isn't that right SK?

Last edited by sobast; 19th Dec 2007 at 08:19.
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Old 20th Dec 2007, 19:45
  #38 (permalink)  
 
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This just gets better, so the bottles are different colours are the carts not white and red respectively too?

So these were engineers and not baggage handlers doing push backs...
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Old 21st Dec 2007, 10:34
  #39 (permalink)  
 
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I hate to say it, but it could have just been a monumental brain explosion.
18th December 2007 01:09
Maybe a new Queens birthday honour award for LAME's that Fuc,k up ..... give them a ' MBE ' (Monumental Brain Explosion)
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Old 21st Dec 2007, 10:45
  #40 (permalink)  
 
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BTW..... I am taking nominations...... bag chuckers may apply
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