FAO Scy11a, Crazyscot

Risks Digest 24.93
Date: Fri, 21 Dec 2007 21:24:51 -0600
From: Peter G Neumann <>
Subject: Nitrogen Used To Fill Aircraft Oxygen Systems

Airlines all over the world are being warned to check to make sure
there's 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 that's 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 didn't 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.

See also:
  • Current Location: the boxroom
  • Current Mood: horrified and amused
  • Current Music: Saul Williams - Black history month
I thought that aircraft didn't carry oxygen but chemical oxygen generators, at least for the main masks-that-drop-down stuff; possibly they have other contexts for oxygen, like medical supplies.
This varies between aircraft types, some use oxygen cylinders for the oxygen masks. If you need therapeutic oxygen (which I think is stored separately, in hand-carryable cylinders), I don't think one can substitute therapeutic nitrogen either.

Overall, who needs terrorists when we've got stupids?
Ah, thanks for that.

The therapeutic oxygen was what I meant by medical. Either way, it'd be extremely bad news for anyone trying to breathe it.
I could see airlines wanting to carry therapeutic oxygen for passengers with breathing problems and therapeutic (... from the crew point of view) nitrogen for really annoying passengers...
Oxygen comes in bottles with oxygen connectors - therapuetic or not. Nitrogen comes in bottles with nitrogen connectors. They do not mate with oxygen connectors. So, in fact, you have to be quite clever or at least ingenious to fill an O2 tank with N2 or in fact anything other than oxygen.
As noted in the article, the stupids concerned were quite ingenious enough to swap the nonworking (correct) connectors on the nitrogen cart with their working (incorrect) connectors from their previous oxygen cart.
Just weld the connectors on; the idiots will set fire to themselves trying to detach the oxygen connectors with welding kit and that'll solve the problem.

.. you still flying for that orange airline, or not? Still hoping to get on one of your flights and say hello.
That's carrying in the sense of "in the hold". Having them installed is still OK, and some currently-produced aircraft use them, eg the A330.
Also, oxygen for the flight crew is supplied from cylinders. Supplying them with nitrogen instead could cause a safety hazard since most current safety procedures for smoke or fumes in the cabin begin with "pilots should immediately begin to use oxygen masks".
They may do, or some may do. I don't know the current situation, but according to this FAA page,

The carrying of oxygen generators on passenger aircraft was banned following an in-flight cargo fire and subsequent crash of a ValuJet DC-9 near Miami, Florida, on May 11, 1996. The probable cause of the accident was determined to be the inadvertent activation of one or more oxygen generators in the forward cargo compartment that resulted in an uncontrollable fire

This does not, of course, mean that the situation hasn't changed since, or that other kinds aren't now used.
Actually, it looks like that means carrying them as cargo is banned, rather than their installation.
Yes, so if we drop the 'rubber jungle' then the plane is effectively grounded until we can get spares sent out by road or ship : ( (or, of course, we could fly it back unpressurised or without passengers which would be cheaper).

Crew have a big O2 bottle to ourselves, and cabin attendents have therapuetic / portable oxygen bottles, but in the first instance they just sit down and use spare masks from the drop-down passenger oxygen
on a stick.

I can't get the image of what would happen when the masks dropped down out of my head.

That is one magic fuckup.
Actually, the passenger oxygen would've been fine as that produced from oxygen generators in the overhead passenger service units. The flight deck crew get their O2 from a bottle which gently depletes as we have to do daily checks on the supply and also tiny leaks. At EZY they have to send the bottles away and put in a new one for just this reason - to protect against f*ck ups! Also, to reassure all you nervous passengers, the first action cabin crew take in case of a pilot incapacitation is to administer their own therapeutic oxygen, so the chances of all of them being filled with N2 is quite remote.
hmmmm, Australian air support crews strike again.... don't let them touch your baggage either!
*yawn* old news. Been round the block on Pprune already. A pal of mine watched as a work experience guy attempted to fill a hydraulic accumulator with oxygen instead of nitrogen. Hydraulic fluid is highly flammable under heat and pressure...
More scary is the story about hackers and the new B787 Dreamliner
That's not entirely new news either.

You've come across Windows for Warships, I take it?
A subsidiary of BAe is standardising the control systems for British warships on Windows 2000.
I know where they should, but I'm sure they won't.

Note also this fine effort :
>>Declan - GCN followed up the story cited below with this one
>>( in which the same
>>author wrote:
>>"Human error, not Microsoft Windows NT, was the cause of a LAN failure
>>aboard the Aegis cruiser USS Yorktown that left the Smart Ship dead in the
>>water for nearly three hours last fall during maneuvers near Cape Charles,
>>Va., Navy officials said.
>>The Yorktown last September suffered an engineering LAN casualty when a
>>petty officer calibrating a fuel valve entered a zero into a shipboard
>>database, officials said. The resulting database overload caused the ship's
>>LAN, including 27 dual 200-MHz Pentium Pro miniature remote terminal units,
>>to crash, they said.

The two issues, of course, being why the input wasn't sanitised and how a database error managed to bring the whole network down.
Hm, and I spend my working days flying an aircraft with no physical connection between the flight controls and sidestick, and running multiple ficcal and tempremental computers which include several Wondows-based components.

That inspires me with so much confidence.
Reassuring or what? Lucky it wasn't hydrogen or we'd all be talking in a high-pitched voice.