Aircraft Washing

[canjond]

I am doing a research project for my environmental law class on aircraft washing and how they are regulated to prevent adverse effects on the environment. I have read online that certain service manuals of aircrafts specify types of soaps that can be sued to wash an airplane, soaps that will not affect the outer surface of the aircraft or harm the environment. I have tried, albeit without any luck, to obtain some service manuals to see exactly what they say... do they just describe washing procedures?; products that can be used?; are there product lists?; etc. If anyone can help me or give me some more direction, I would greatly appreciate it. Thanks!

 

[Loafman]

People actually WASH airplanes? At Eagle, they just use them to grow experimental dirt.

 

[ShawnC]

Well other than the windows, at my airport we use this special enviromentally friendly soap to was our airplanes. It's called rain water.

 

[A Squared]

Washing Airplanes

Much Hysteria and mis-information surrounds washing airplanes. Not long ago it was published in an aviation publication that SImple Green was *CORROSIVE* Shock-Horror !!!!! An immediate panic ensued in all who had been using Simple Green on aircraft.


Ummmm, folks, All cleaners are corrosive to some degree, because they are all alkaline to some degree. Take any of the the cleaners under your sink and apply it to unfinished aluminum and leave it for a while without rinsing... they are all going to leave a dulled spot (corrosion) even dish soap.

Now, back to simple green. If you look at the Material Data Safety Sheet (MSDS) for Simple Green, you will find that it has a Ph of 9.5, which means that yes, it is Alkaline (anything over 7 is alkaline, less than 7 is acidic) OK,. now for contrast, take a look at the MSDS for Carbon-X an *approved* aircraft cleaner, which meets MIL-C-257 69 E (whatever that is). The Ph of Carbon-X is listed as 12.5 to 13, which makes it *more* corrosive than Simple Green, yet Carbon-X is supposedly safe for use on aircraft. (bear in mind that 14 is the extreme end of the the Ph scale, that alkaline wasteland inhabited by things like sodium hydroxide, otherwise known as lye) Go figure. It is also interesting to note that the chemical ingredidnts for the two cleaners are pretty much the same.

If you use *any* detergent or cleaner on an airplane, make sure you rinse it very thouroughly with lots of clear water.

 

[ThomasR]

Environment

.......... I have tried, albeit without any luck, to obtain some service manuals to see exactly what they say... do they just describe washing procedures?; products that can be used?; are there product lists?; etc...............

My background is in helicopters. I never saw a military aircraft get washed in all my 16 years with the army inventory. The military has manuals and procedures on everything, I'm sure they have a list of products approved for washing aircraft. In the civilian market flying offshore in is a corrosive environment mixing dirt, dust and salt through engine intakes, leading edges and windshields. We washed aircraft as a matter of post flight procedures both the fuselage and combustion chamber. Most of the time it was just a water rinse through a garden hose and nozzle. Once in awhile maintenance used some kind of sudsing agent but I never payed much attention to the products used.

 

[avbug]

Simple green really is very corrosive to aircraft, as is Purple K and other degreasing agents.

PH is only part of the equation; reactivity with aluminum and magnesium is a bigger issue.

Washing the chemical from the aircraft is not enough. Capillary action draws the chemicals into faying surfaces where it is retained for extended periods, contributing to corrosion which is difficult to locate or control.

Individual maintenance manuals always include cleaning washing practices and proceedures, applicable to any given specific airplane.

Certain washing operations (such as a compressor wash) requires distilled water. Some operations require specific cleaners or cleansers, and call for Stoddard Solvent, MEK, or other specific cleaning agents. Additional specific precausitions apply to each cleanser. Disposal of rinse and rinsate is controlled by local, state, and federal laws.

 

[avbug]

Apparently due to a ridiculous change to the forum, a message can't be edited after ten minutes has elapsed after posting...so I find myself adding material by making a reply to myself.

To continue from before...

Washing an airplane is the same as washing a car, for the most part. Certain chemicals should not be used, as these react adversely with aluminum and magnesium. Washing degreasing agents such as simple green, purple K and others tend to be highly corrosive to aircraft, and should never be used.

Some airports utilize "wash racks" that capture rinse water and funnel it into a drain system, usually utilizing an oil separator. Many airports do not, and washing an airplane amounts to the same thing as washing a car. Soap on, scrub, wash off.

Aircraft utilizing Avgas have lead deposits in any exhaust stains or exhaust deposits, which comes away with scrubbing and rinse water. No guidelines have been established for dealing with this minimal hazard, or any other hazardous waste materials which might attend washing aircraft.

Specialized operations involving dispensing of materials from aircraft do have certain guidelines attached for rinsate of chemicals or materials which might adhere to the aircraft, it's systems, etc.

In general, the guidelines you're searching for don't exist.
On the subject of washing agents and military specifications (milspec), don't make the assumption that because something has been issued a milspec designation, or in other words that because something meets a military specification, it's acceptable for any other use. A military specification is not an approval for use; its a statement of certain criteria which must be met by an agent, chemical, part, etc. It is not a general or specific authorization. Aircraft manufacturer or component manufacturer guidelines always take precedence, though these may call out a specific item by military specification or other standard.

A given grease, for example, while having a milspec designation such as mil-81322 (aeroshell 5) may be highly desirable for a specific application on a specific airplane such as wheel bearings. It is not compatable with certain other greases however, which also hold a milspec designation, and the mixing of the two (aeroshell 22, for example) can be disasterous under the right circumstances. Look to the aircraft manufacturer for specific recommendations or cautions first, and then to other sources.

For the most part, standard dish soap is hard to go wrong with. In times past, I've also found that Zep high foam degreaser does a very credible job. Don't make assumptions with cleaners, however. What is appropriate on one surface may not be appropriate on another.