Mercury Contamination

[Steamhead]

Understanding that mercury contamination of the airframe is a no no, how does one identify the problem and what does it do to the metal.

[aeroguru]

Once saw it after a big bag full of African eels split and spewed it's contents into the belly area.Don't know how the eels got the contamination but it just eats al.alloys and embrittles frames and stringers.You have to cut out all the damage ruthleessly,
I hate to think what happened to all the eels in the other bags and who ended up eating them!

[CCA]

We used to x-ray the bilge area when there was a suspected spill, it sticks out like dogs balls.

[Genghis the Engineer]

Aluminium (and pretty much all of its alloys) is incredibly reactive with air. This actually protects it because aluminium oxide forms on the surface in about a nothingth of a second which is then impervious to pretty much anything and protects the aluminium.

However, aluminium oxide dissolves http://www.pprune.org/ubb/NonCGI/eek.gif very http://www.pprune.org/ubb/NonCGI/eek.gif quickly in mercury (and just about nothing else). So, the mercury keeps stripping off the protective oxide, immediately after which the oxide re-forms from fresh aluminium - well you get the picture.

So, in a fairly short time, the mercury effectively eats its way through the aluminium. I've not tried it, but I'm told that with a spare bit of alloy sheet and a test tube of mercury a rather educational demo can be done.

G

[Blacksheep]

A problem that cost us hundreds of manhours and tens of thousands of dollars when nobody checked the contents of "Medical Supplies" before loading. In the end we cut out the frames and re-skinned the aft cargo belly -- twice. You can find the extent of the spillage by using Flowers of Sulphur, mixed into a paste and spread all over the suspected area and beyond. The paste dries on yellow and is harmless but amalgamates with any minute amounts of mercury to form various sulphides of mercury clearly seen as black patches. This makes the full extent of the contamination visible. Then you get out the saws drills and rivetting guns, there's no safe way to clean it up! The mercury gets in everywhere and if you don't re-build, the affected parts are eaten away faster than the "C" Checks come round.

Be careful working in the area, mercury vapour will be in the air and it can be absorbed through the skin. It is a very nasty poison and once in the body Mercury is not excreted, you just build up a lifetime dose. Good Luck!

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Info noted. Plse report further.

[Steamhead]

Thanks everybody for the very informative replies.
I heard on the grapevine that Boeing had
advised scrapping of an aircraft recently
because of this problem also a heavy maintainence organisation in the u.k. has had to do some re-skinning recently.

[forget]

In 1967 the RAF had a Britannia make a one way trip to Nebraska. It was hauling support equipment for a bombing competition – Vulcans verus B-52’s. On arrival a piece of test equipment was found to be broken in its carton and a load of mercury had disappeared into wherever. The RAF left the aircraft there.

Incidentally, the Vulcans won.

( My grammar checker is telling me that ‘was found to be broken’ is ‘Passive Voice’. What the hell is that? )

[Genghis the Engineer]

Passive: was found to be broken
Active: I broke it
Accusative: You broke it

Now you know why passive voice is always used in engineering reports.

[forget]

Genghis - God you're sharp. Now I know.

The spooky thing is - the bombing competition I referred to was code-named Giant Voice. When I saw this reminder, 'Passive Voice', I thought Bill Gates had maybe gone a step too far!

Sorry Genghis - 'the bombing competition to which I referred.....

[This message has been edited by forget (edited 11 February 2000).]

[Wino]

It was evergreen that had the spill recently. They had to write off one of their younger 747s....


Wino

[Blacksheep]

Giant Voice! Aaaaahhh.... I remember it well.
Of course, being an irreverent bunch we immediately renamed it "Big Mouth" Something to do with the locals over there ;)

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Through difficulties to the cinema