What Aircraft Owners Should Know About Dry-Wash Methods

A dry wash cleans the exterior with products applied and wiped off by hand instead of washing and rinsing with running water. The FAA describes it as a method for removing airport film, dust, and light dirt when liquids are not desirable or practical, and says it is not suitable for heavy deposits of carbon, grease, or oil, especially in exhaust areas. Used on the right aircraft for the right job, it is practical; used on a heavily soiled surface, it risks dragging grit across the finish.

How the FAA describes dry washing

The FAA’s Aviation Maintenance Technician Handbook lists three ways to clean an aircraft exterior: wet wash, dry wash, and polishing. Its description of dry washing is brief and useful:

• It removes airport film, dust, and small accumulations of dirt and soil
• It is used when the use of liquids is neither desirable nor practical
• It is not suitable for heavy deposits of carbon, grease, or oil, especially in engine exhaust areas
• Products are applied with spray, mops, or cloths and removed by dry mopping or wiping with clean, dry cloths

The handbook adds that the type and extent of soiling, and the final appearance wanted, determine which cleaning method should be used. In other words, dry washing is a tool for a particular kind of dirt, not a replacement for every wash.

“Dry wash” also covers a range of commercial products, from rinseless washes that use a small amount of water to sprays applied and buffed off. Their chemistry varies, which is why compatibility matters.

Why owners and operators choose it

• Facility limits. Some hangars and ramps do not have a wash rack, a water supply, or drainage, or they restrict washing. Facility rules vary by airport and must be confirmed per job.
• Less water near sensitive areas. FAA AC 43-4B recommends protecting against water and cleaning compound intrusion at openings, vents, and pitot-static openings. Airbus has published an in-service event where a high-pressure jet forced water into a landing gear sensor through a vent. Using less water reduces, though does not remove, that concern. Sensitive areas still need protection and care.
• Weather and season. When it is too cold to wet wash comfortably or safely, or water would freeze, a dry method may be the practical option.
• Maintenance between washes. On an aircraft that is mostly clean, a dry wash can handle light dust and film without a full wet wash.

The main risk: grit

Wet washing floats dirt off the surface and rinses it away. Dry washing lifts dirt into a product and a cloth, and if there is too much dirt, or the cloth is not changed often enough, abrasive particles get dragged across the surface. FAA guidance on transparent plastics makes the same point in a different context: rubbing with a dry cloth is likely to cause scratches and builds static that attracts more dust.

This is why dry washing suits light soil and why heavy dirt, mud, sand, and grime usually call for wet methods or pre-cleaning first.

Other considerations

As with any cleaning product, the aircraft manufacturer’s handling and service guidance and maintenance manual, and the paint and transparency manufacturers, set what is acceptable. A provider should be able to tell you which product they intend to use and why it suits your aircraft.

Dry wash or wet wash: a decision guide

• Light dust and airport film, aircraft hangared: a dry wash is often a reasonable fit.
• Bugs on leading edges: may need softening and a method suited to the surface; a dry product alone may not be enough.
• Heavy belly grime or exhaust soot: wet methods or targeted cleaning are usually needed, per FAA guidance on dry-wash limits.
• Mud, sand, or heavy dust after outdoor storage: wet wash or a thorough pre-rinse first, to avoid grinding grit into the finish.
• No water allowed at the facility: dry methods may be the only option, which affects what is realistic for a heavily soiled aircraft.

Water-related concerns like spotting are covered in water spots on aircraft finishes. If you are working out whether on-location work is possible at your airport, see mobile aircraft detailing: access and facility questions.

Where dry washing fits in ongoing care

Because it suits light soil, dry washing tends to work best as part of regular attention, keeping an already clean aircraft from building up dirt. That is one reason it often appears in recurring aircraft care arrangements, with periodic wet washing when conditions call for it.

Requesting a quote

When you request a quote, let us know how the aircraft is stored, how dirty it is now, whether the facility allows water use, and any product restrictions in your aircraft’s documents. That helps us discuss whether a dry method, a wet wash, or a combination fits, subject to airport and facility approval.