Procedures and Methods

Airworthiness Regulations :

✈

_{Appendix D of CASR}

_/

_{14 CFR (FAR) Part}

43

requires –

inspection.

There are Two (2) kinds of Aircraft

Cleaning:

1. Exterior

Cleaning

, and

2. Interior

Cleaning

.

• Aircraft Exterior Cleaning = Aeroplane Structural Surface Cleaning.

Aircraft Cleaning



C

A

K

I

C

–

E

,

:

• Dirt _{: – can cover up cracked or damaged}

components, as well as trap moisture and solvents that lead to corrosion.

• Dirt and debris_{, if accumulate over time, can build}

to a considerable weight and decrease the useful load of the aircraft.

• Dirt _{– can hide crack in the skin.}

• A film of dirt _{- if left on the aircraft’s outer surface,}

reduces flying speeds (increase drag) and adds

Reasons for a/c cleaning. . . (cont’d):

• Dust and Grit – cause hinge fitting to wear excessively.

• A cracked Landing Gear Fitting covered with

mud and grease – may be easily overlooked.

• Dirt or Trash _{blowing or bouncing around the}

inside of the aircraft is annoying and dangerous.

• Small pieces of Dirt _{blown into the eyes of}

the Pilot at a critical moment – can cause accident.

Aircraft Cleaning

• Reasons for a/c cleaning. . . (cont’d):

• A coating of Dirt and Grease on moving parts – makes a sort of grinding compound that can cause excessive wear.

• Salt water has serious corroding effect on

exposed metal part of the aircraft, and it should be washed off immediately.

• It also helps to promote a good image to

customers – and makes the aircraft more pleasant to work on.

Aircraft Cleaning

Reasons for a/c cleaning. . . (cont’d):

• Moreover, clean aircraft as a whole & its component parts should be kept clean, since this helps to :

– Reduce Wear;

– Allows for Leaks to be more readily detected,

– Reduce Crevice Corrosion, and

– Makes the a/c more aerodynamic (for surface cleanliness).

 Therfore, the cleaning of the aircraft exterior and interior should not be taken lightly (jangan dianggap enteng) .

Aircraft Cleaning

• Materials and procedures presented in the

textbooks are intended only as Guidelines.

• When performing the work, Mechanics / Technicians – should always follow

manufacturer’s recommendations for :

Cleaners, Solvents, and Cleaning Procedures.

Aircraft Cleaning

Maintenance crews wash an airplane at the gate.

Kru pemeliharaan mencuci pesawat di pintu gerbang.

EXTERIOR CLEANING :



_{There are}

_{3 (three) Methods of Cleaning}

the Aircraft Exterior :

(1) Wet – wash

(2) Dry – wash, and (3) Polishing:

a. Hand Polishing, and b. Mechanical Polishing.

 Cleaning method to be used – is determined by:

♦ _{The Type & the Extend of Soiling, and} ♦ _{Final Desired Appearance}

Aircraft washing /

cleaning

(1) W

W

M

• Removes Oil, Grease, or Carbon deposits,

and most Soils, with the exception of Corrosion and Oxide films.

• The cleaning compounds used are usually applied by spray or mop, after which high-pressure running water is used as a rinse.

• Either Alkaline or Emulsion cleaners can be used in the wet-wash metohd.

EXTERIOR CLEANING :

(2)

D

W

M

:

• Is used to remove Airport film, Dust, and Small Accumulation of Dirt and Soil, when the use of liquid is neither desirable nor practical.

• This method is not suitable for removing heavy deposits of Carbon, Grease, or Oil, especially in the engine exhaust areas.

• Dry-wash materials are applied with Spray,

Mops, or Cloths, and Removed by dry mopping or wiping with clean, dry cloths.

(3) P

:

• Restores the luster to painted and unpainted surfaces of the airplane, and is usually

performed after the surfaces have been cleaned. • Polishing is also used to remove oxidation and

corrosion.

• Polishing materials are available in various forms and degrees of abrasivness. It is important that the aircraft manufacturer’s instructions be used in specific applications.

EXTERIOR CLEANING :

The washing of aircraft should be performed in the shade whenever possible as the cleaning compounds tend to streak the surface if applied to hot metal, or permitted to dry in the area.

►WHEN WASHING AN AIRCRAFT :

• The Aircraft should be parked on a wash rack, or in an area where it can be hosed down.

• Avoid washing an aircraft in the sun to help prevent the surface from drying before the cleaner has time to penetrate the film and dirt.

• For the main part of the a/c exterior, use a 1:5 or a 1:3 mixture of water and an emulsion–type cleaner that meets MIL-C-15769

specifications.

• Brush or spray the mixture on to the surface and allow it to stand for a few minutes, then

• Rinse it off with a high-pressure steam of warm water.

►Certain Areas and Components must be Protected :

a) Install covers over all openings where water or cleaners might enter and cause damage.

b) Pitot Tubes and static openings – should always be plugged or taped prior to cleaning an a/c to prevent water ingestion.

c) Wheel and Break assy – should be covered to keep out cleaning agents.

d) Engine Cowling and Wheel Well area usually have grease or oil deposits that require special

treatment.

EXTERIOR CLEANING –

BEFORE S

W

A

:

 Various Areas of Aircraft, such as:

1. The Sections housing radar and the Area forward of

the cockpit that are finish with a dull paint, should not

be cleaned more than necessary and should never be scrubbed with stiff brushes or coarse rags.

• A soft sponge or a cheese-cloth with a minimum of manual rubbing is advisable.

• _{Any oil or exhaust stains on the surface should first be}

removed with a solvent such as karosene or other petroleum-based solvent.

• _{The surface should be rinsed immediately after cleaning}

to prevent the compound from drying on the surface.

EXTERIOR CLEANING –

2. Engine Exhaust:

• Stubborn Exhaust stains – may require a 1:2 mixture of cleaner with Varsol or Kerosene. • Mix these ingredients into a creamy emulsion

and apply it to the surface. Let it stand for a few minutes,

• Then work all of the loosened residue with a bristle brush (sikat ijuk/jerami), and hose it off with a high – pressure stream of warm water. • Repeat this treatment, if the first application

does not remove all of the stain.

18

EXTERIOR CLEANING –

♦_{Before applying Soap and water to Plastic or}

Plexiglass surfaces, Flush the plastic surfaces with fresh water to dissolve salt deposits and wash away dust particles.

• _{Plastic surfaces should be washed with soap and water,}

preferably by hand. Rinse with fresh water, and Dry

with chamois or absorbent cotton.

♦ _{In view of the Soft surface, do not rub plastic with a}

dry cloth since this is not only likely to cause scratches, but it also builds up an electrostatic charge which

attract dust particles to the surface.

• The charge, as well as the dust, may be removed by

patting or gently blotting with a clean damp chamois.

EXTERIOR CLEANING –

NONMETAL

SURFACES

• Do not use scouring powder or other material which can mar the finish.

• Remove oil and grease by rubbing gently with a cloth wet with soap and water.

• Do not use Acetone or Benzene, Carbon Tetrachloride, Lacquer Thinners, Window

Cleaning sprays, Gasolines, Fire Extingushers, or De-icer Fluids on Plastics bacause they

soften the plastic and cause crazing.

EXTERIOR CLEANING –

NONMETAL

SURFACES

• Surface Oil, Hydraulic fluid, Grease, or Fuel can be removed from aircraft’s tyres (tires)

by washing it with a mild soap solutions.

• After cleaning, lubricate all grease Fittings,

Hinges, etc..., where removal, contamination, or dilution, of the grease is suspected during washing of the aircraft.

EXTERIOR CLEANING –

NONMETAL

SURFACES

Aircraft Cleaning Agents

• The Type of Materials to be used in cleaning depends on the nature of the elements that need be removed.

• In general, Types of Cleaning Agent used on aircraft are: Solvents, Emulsion Cleaners, Soaps, and Synthetic Detergent.

 Their use must be i.a.w the applicable Maintenance Manual.

The Soap and Synthetic Detergent type

cleaners – are used for Light-duty cleaning, while

The Solvent and Emulsion type cleaners – are used for Heavy-duty cleaning.

The Light-duty cleaners, which are non-toxic

and non-flammable, should be used whenever possible.

Aircraft Cleaning Agents

 SOLVENT CLEANERS.

• In general, solvent cleaners used in a/c cleaning should have a flashpoint of not less than 105° F, if explosion proofing of equipment and other

special precautions are to be avoided.

• Chlorinated solvents of all types – meet the non-flammable requirements but are toxic, and safety precautions must be observed in their use.

• Use of Carbon Tetrachloride - should be avoided.

 Dry-Cleaning Solvent.

• Stoddard solvent – is the most common petroleum-based solvent used in aircraft

cleaning. Its flashpoint is slightly above 105° F and can be used to remove grease, oils, or light soils.

• Dry-cleaning solvent – is preferable to kerosene it leaves a slight residue upon evaporation which may interfere with the application of some final paint films.

26

 Aliphatic and Aromatic Naphta :

• To remove Oil, Grease, or Soft Preservative

Compounds, dry-cleaning solvent or Naphta, is often used.

• There are two most common types of Naphta are: Aliphatic Naphta and Aromatic Naphta.

a) Aliphatic Naphta – is a hydrocarbon solvent

that dissolves oil and grease, but does not harm rubber or acrylic components.

Aliphatic Naphta (cont’d) – because it is safe on most materials, therefore, it is recommended for wipe-down of cleaned surface just before painting. It flashes at approximately 80° F., and must be used with care.

b. Aromatic Naphta – should not be confused with the aliphatic material. It is toxic and

attacks acrylics and rubber products, must be used with adequate controls.

28

Other Solvent Cleaners :  _{Safety Solvent.}

 Methyl Ethyl Ketone (MEK).

 Kerosene.

 Cleaning Compound for Oxygen Systems:

anhydrous (waterless), ethyl alcohol, isopropyl (anti-icing fluids) alcohol, or a mixture of freon and isopropyl alcohol.

 EMULSION CLEANERS.

• Solvent- and water-emulsion compounds are used in general a/c cleaning. Solvent

emulsions are particularly useful in removal of heavy deposits, such as Carbon, grease, oil, or tar.

• When used i.a.w. Instructions, these solvent emulsions do not affect good paint coatings or organic finishes.

30

 SOAPS AND DETERGENT CLEANERS.

• A number of materials are available for mild cleaning use. In this section, some of the more common materials are discussed.

MECHANICAL CLEANING MATERIALS.

• Mechanical cleaning materials must be used with care and i.a.w directions given, if damage to finishes and surfaces is to be avoided.

• Examples :

– Mild Abrasive Materials;

– Abrasive Papers.

32

 CHEMICAL CLEANERS.

• Chemical cleaners must be used with great care in cleaning assembled aircraft. The danger of entrapping corrosive

mateials in faying surfaces and crevices counteracts any advantages in their speed and effectiveness.

• Any material used must be relatively neutral and easy to

remove. It is emphasized that all residue must be removed.

• Soluble salts from chemical surface treatments such as chromic acid or dischromate treatment will liquefy and promote blistering in the paint coatings.

• Procedures when using Chemical cleaning agents – (read in your text: JSAT , pg 12-3, 12-4).

Table: CLEANING AGENTS - F.Y.I*

34

DESIGNATION SPECIFICATIONS

(SPECS)

USES

Aircraft Exterior Turco Air Tec USA (MIL-C- 087936)

General Purpose Aircraft Exterior Cleaner. Liquid Detergent

Concentrate

Ardrox 6025 (MIL – C – 87936)

Cleaner and Stain Remover.

Varsol / White Spirit UK; and USA Cleaning Solvent for Mechanical Parts. Tri- chloro-ethane

(Methyl Chloroform)

Genklene , USA Cleaning Solvent.

Tri-chloro-tri-fluor-ethane Frcon TF Cleaning Oxygen System Pipe Lines.

Isopropyl Acohol Air3660 ; France; USA General Cleaning.

Table: CLEANING AGENTS

- F.Y.I* -

(cont’d)

DESIGNATION SPECIFICATIONS

(SPECS)

USES

Rain Repellant Cleaner Altupol Cleaning Rain Repellant Off Windscreens.

Safety Solvent USA Odour Free Sovent Cleaning Agent. Stain Remover Teepol

(MIL-D-16791) Dry Cleaner PD 680

(BS 245: 76 Type 1)

Solvent for Cleaning Mechanical Parts. Plastic Polishing

Compound (fine grade)

PP-560 USA

Paste for Polishing Plexiglass.

VDU Cleaner Alglas V Anti Static Flight – Deck CRT Screen Cleaner.

EXTERIOR FINISH MAINTENANCE

• A clean, polish surface prevents corrosion from starting to take place. Therefore, a/c should be kept clean and waxed.

• All drain openings must be kept open, and

deposits formed from engine exhaust must be removed before they build up excessively.

• Do not use harmful cleaning, polishing,

brightening, or paint removal materials to avoid damage to the aircraft.

EXTERIOR FINISH MAINTENANCE

• Use only – those Compounds which conform to existing government or established industry

specifications, or Products that have been specifically recommended by the aircraft manufacturer as being satifactory for the intended application.

• Observe the product manufacturer’s

recommendations concerning the use of their agent.

EXTERIOR CLEANING –

After Airframe Cleaning

CHECKING

 _{After cleaning the Airframe, CHECK ALL DRAINS to see}

that they are Clear and Make Sure water/cleaning liquid has NOT entered parts of the A/F, such as:

– Engine Intake and Exhaust.

– Pitot Static Vents, etc.

– Windows, Doors, and Hatches.

– Air Conditioning Vents.

– Cooling Grills.

– Drain Holes.

• Glass Windscreen – can be washed with a non-acid soapy

solution and cleaned with a chamois leather and

• Plastic Windows – can be washed with the same solution

and cleaned with a fine grade plastic polishing compound.

INTERIOR CLEANING

• Keeping the interior of the aircraft clean is just as important as maintaining a clean Exterior surfaces.

• Corrosion can establish itself on the inside

structure to a greater degree because it’s difficult to reach some area for cleaning.

• Nuts, bolts, bits of wire, or other metal objects

carelessly dropped and neglected, combine with moisture and dis-similar metal contact, can cause electrolytic corrosion.

• The following Cleaning Operation procedures for aircraft interior are taken from “The

National Fire Protection Association (NFPA) Bulletin # 410F “Aircraft Cabin Cleaning

Operations”.

INTERIOR CLEANING



TYPES OF CLEANING OPERATIONS.

• The principal areas of a/c cabins which may need Periodic Cleaning are :

(1) Aircraft Passenger Cabin areas (seats, carpets, side

panels, headliners, overhead racks/ stowage bins,

curtains, ash trays, windows, doors, decorative panels of plastics, wood, or similar materials).

(2) Aircraft Flight Station areas (similar material to those

found in pax cabin area plus instrument panels, control pedestal, glare shields, flooring materials, metallic

surfaces of instruments, and flight control equipment, electrical cables, and contacts, etc.).

 TYPES OF CLEANING OPERATIONS (cont’d) (3) Lavatories and Buffets areas (similar

material to those found in pax cabin area plus toilet facilities, metal fixtures and trim, trash containers, cabinets, wash and sink basins, mirrors, ovens, etc.).

INTERIOR CLEANING

A. Non-flammable Aircraft Cabin Cleaning Agents and Solvents:

1) Detergent and Soaps. 2) Alkaline Cleaners.

3) Acid Solutions.

4) Deodorizing or Disinfecting Agents. 5) Abrasives.

6) Dry Cleaning Agents.

Aircraft Cabin Cleaning Agents

B. Flammable and Combustible Agents :

1) High Flash Point Solvents. 2) Low Flash Point Solvents. 3) Mixed Liquids.

44

POWERPLANT CLEANING

• Accumulated dirt on PP – can cover defects and

lead to overheating. Therefore, a/c engine should be cleaned on regular basis.

• When cleaning PP, all electrical components in the engine compartment must be protected from solvent and soap. This include – wrapping the

magnetos so no water can get in the vents.

Aircraft wash

–

Deicing operation on horizontal

stabilizer

Operation performed in the airport

Deicing operation on horizontal stab of Boeing 747

Boeing 737 horizontal stabilizer being deiced

(photo credit: Jeff Walsh)

D

AFTAR

P

USTAKA

/R

EFERENCES

:

JEPPESEN Sanders Maintenance.  Ch. 12, sect.A;

2. FAA – AC 65-9A: " Airframe & Powerplant Mechanics

,General Handbook “, Consolidated Reprint (includes

CHG 1, dated 3/31/99); Chapter 06.

3. FAA AC 43.13-1B: Chap. 06 – “ Corrosion, Inspection, & Protection ”.

4. CASR Part 43 Appendix – D. 5. FAA- 14CFR/FAR Part 43 – D. 6. EASA –Airbus.

Glossary

• Compound : senyawa, campuran.

• _{Soiling (dirtying) : mencemari; mengotori.}

• Streak (to scratch): menggores, mencoreng; mencoret;

• Lacquer thinners: pengencer pernis/vernis.

• Harmful: membahayakan.

• Hazzardous: berbahaya.

• _{Crevice: celah, belah,rekahan}

• Mar (spoil, defect, deface) : cacat, cedera, mengelupas.

• Wear (to deteriorate, to wear out) : aus; usang

• Flashpoint /flash-point (point at which

something is ready to blow up): titik nyala.

• Combustion: pembakaran.

• Combustible: mudah menyala, dapat/mudah terbakar;

• Flammable: mudah terbakar, dapat terbakar/ tersulut.