Contamination of Bleed Air

[RvB]

Hello, I talked to a maintanance engineer the other day who told ma about a new method of cleaning the inside of an jet engine and thereby augmenting its performance.It´s basically achieved by water injected under high pressure.The water leaving the compressor stage of the engine is supposed to be that contaminated by traces of heavy metals like nickel,cobalt and chrome that the washings cannot be disposed into the regular sewage water and have to be handled like hazardous waste.
Of course there are more sources for bleed air contamination further downstream as well.
Has anyone ever heard about, or made the experience of physical reactions caused by respirating bleed air through the air conditioning system ?
Is that an issue already discussed earlier ?

Best regards, RvB.

[NSEU]

Is that an issue already discussed earlier ?

Extensively :) Try, maybe, "fumes" as a search word???

"Hello, I talked to a maintanance engineer the other day who told me about a new method of cleaning the inside of an jet engine ..."

Not sure that it's new... our airline has been using it for decades. For some reason, we did it on a customer aircraft (who normally didn't have it done).. and they were amazed with the improvement in engine performance.

Rgds
NSEU

[pjvr99]

Water will mostly take off loose dust, flakes etc, and does increase performance. Normally a detergent of some sort will also be added to the water, to remove the stuff that has solidified on the compressor blades, and remove carbon from the combustion chamber(s) and turbine. Unfortunately, these detergents do need to be collected and special procedures followed for disposal.

[wbble]

RvB,

As well as all the nasties from engine oil entering the bleed air, I think it is very likely that the heavy metals you talk about get into the bleed air too. Blood test results from a group of pilots in 2006 showed unusually high levels of Nickel in most of them, and antimony, beryllium and cadmium were also found. Nickel is extensively used in alloys for compressor blades, and I believe the other metals are also to be found in jet engines. If this stuff can get squirted off the compressor blades by water, it seems logical that it can also get sucked into the bleed air.

[barit1]

Forty years ago I worked on engines with water jets in the front frame for the purpose of compressor cleaning. At that time we used a petroleum-based solvent mixed with the water, injected it while cranking on the starter, then let it soak a while to soften the deposits. Then crank it again while spraying demineralized water to flush the flowpath.

As NSEU says, the improvement was noteworthy.

The cleaner solvent was later decreed unfriendly to the environment, and a new protocol was developed, but I don't have those details at hand.

[Old Fella]

I think a "Night on the Tiles" in most Asian ports would be more hazardous to health than any "nasties" in the air within the aircraft environmental system.