ATO CORROSION

What four conditions must exist for corrosion to occur?

A metal must be present (Anode) Dissimilar Conductive material (Cathode) A conductive liquid (Electrolyte) Electrical contact between Anode and Cathode

What should you not do to depleted Uranium?

Abrade or sand

Exfoliation Corrosion

Advance form of intergranular corrosion where the surface grains are lifted up by the force of expanding corrosion products occurring at the grain boundaries just below the surface. Commonly found on Aluminum sheets around steel fasteners. Can be prevented by separating the metals with a barrier.

What must be done in order to guard against the danger of static electricity during all cleaning operations?

Aircraft must be electrically grounded

Volume II

Aircrafts- Provides cleaning and corrosion control procedures for aircrafts.

Intergranular Corrosion

An attack on the grain boundaries of a metal. Rapid Corrosion occurs at the grain boundaries of certain metals when an electrolyte is present.

What is mandatory when applying sealant whenever the previously applied sealant is damaged?

Apply fresh sealant

Highly susceptible to corrosion. This is especially true in helicopters and aircrafts using external ram air-cooling. Technicians should routinely survey this area.

Avionics Equipment Bay

Volume III

Avionics and Electronics- Provides cleaning and corrosion control procedures for avionics and electronics.

This areas contain all types of avionic equipment, providing many places for the following substances to accumulate: dirt, water, Hydraulic fluid, drill shavings, waste, loose fasteners, others debris.

Bilge Area

The three general equipment areas that are COMMONLY affected by corrosion are?

Bilge Area Equipment Bay Area Engine Compartment

Tools used for applying sealant.

Brush Spatula Masking Tape Caulking Gun

Preferred alternatives for touch-up painting since they produce little paint waste and do not require solvent clean up.

Brush and Rollers

What tools are used to apply Paint coating?

Brushes Touch-Up pens Rollers Spray Guns

Crevice Corrosion

Can occur where a stagnant solution has pooled and an electrolyte inside the crevice contains less oxygen and more metal ions than electrolytes outside the crevice.

Volume V

Consumable Materials and Equipment for Avionics- Lists approved materials and equipment for cleaning and corrosion control, and provides ordering information, for avionics only. AIR FORCE ONLY

Volume IV

Consumable Materials and Equipment for aircraft and avionics- Lists approved materials and equipment for cleaning and corrosion control, and provides ordering information.

Prior to using Sealant...

Container must be inspected to determine if the material has exceeded its shelf life.

NAVAIR 01-1A-509

Contains basic corrosion prevention and maintenance information to be used at the Organizational, Intermediate, and Depot levels.

Volume I

Corrosion Program and Corrosion Theory- provides overall program information and explains what corrosion is, why it occurs, the forms it can take, and how to recognize it.

Hot Corrosion

Corrosion in the absence of water can occur at high temperatures, such as those found in turbine engine, compressors, and hot sections.

Fatigue Corrosion

Cracking of metals caused by the combination of fatigue and corrosion. It can cause a reduction in fatigue resistance.

How does a Circulating Drying Oven work?

Dries avionic equipment and components using circulating air and temperature.

Depends on the complexity of the equipment or component being dried and the amount of humidity in the air.

Drying time

Area containing hardware, electrical connectors, terminal boards, junction boxes and ram air turbine which should be inspected for signs of salt spray contamination and corrosion.

Engine Compartment

Magnesium Parts

Extremely prone to corrosion. Special attention must be given to proper treatment of their surfaces, insulation, and paint coating.

The key to successful preventive maintenance

Frequent Inspections and Spot Checks

What is Rubber subject to?

Fungus Growth, which can cause deterioration of the rubber and corrosion of surrounding metal surfaces.

What are the Operational Uses for the Paint System?

Glare Reduction by flat coating Special finishes for reduction of heat absorption Camouflage and other detection countermeasures High visibility requirements Identification markings

Methods of applying Lubricants

Grease guns: lever or pressure type Oil, squirt and aerosol spray cans Hand or brush

Why are Water Entrapment ineffective?

Improper location or because they are plugged by sealants, fasteners, dirt, grease, or debris.

Condensation

Is produced by closed boxes

Two types of batteries found on avionic equipment are?

Lead acid Nickel- Cadmium

Degrees of Corrosion

Light Corrosion Moderate Corrosion Severe Corrosion

Method of fixing Light Corrosion

Light hand-sanding

Moderate Corrosion

Looks like corrosion except that there may be some blisters or evidence of scaling and flaking of the coating or paint system, and the pitting depths may be as deep as 10 mils (0.010 in).

Severe Corrosion

May be similar to moderate corrosion with severe inter granular corrosion, blistering exfoliation, scaling, or flaking. The pitting depths are deeper than 10 mils (0.010 in).

Pitting Corrosion

Most commonly found on Aluminum and Magnesium Alloys. White or Gray powdery deposit, similar to dust, which blotches the surface. When sheet metals become weak they can perforate.

Fretting Corrosion

Occurs at contact areas between materials under load subject to repeated vibrations. Aluminum, Stainless Steel, and Titanium alloys are most susceptible to this type of corrosion because the movement removes oxide coatings.

Galvanic Corrosion

Occurs when different metals are in contact with each other and an electrolyte such as salt water.

The date of manufacture and shelf life can be found where on the sealant?

On each container

New sealant should...

Overlap the existing coating on the roughened surface.

Lubrication

Performs as a dual purpose. Prevents wear between moving parts, but also fills air spaces, displaced water, and provides a barrier against corrosive medium.

Human waste

Products are very corrosive. Areas should be cleaned frequently and the paint finish kept in good condition. Relief tubes are usually made of plastic and should not present a corrosion problem.

Light Corrosion

Protective coating is scarred or etched and the condition of the metal is characterized by discoloration and pitting to a depth of approximately one mil (0.001 in) maximum.

Who selects what methods has to be used when dealing with corrosion?

Qualified Personnel

Air Drying

Recommended for housings, covers and some hardware. It should NOT be used for equipment containing cavities or moisture traps.

What must you do for cold weather cleaning procedures below 40F?

Refer to NAVAIR 01-1A-509-2 Chapter 2

Method of fixing Moderate Corrosion

Removed by extensive hand-sanding or light mechanical sanding.

Method of fixing Severe Corrosion

Removed by extensive mechanical sanding or grinding.

Uniform Surface Corrosion

Results from a direct chemical attack on a metal surface and involves ONLY the metal surface. The metal gradually becomes thinner and eventually fails.

Prevents the intrusion of moisture, rain, saltwater, dust, and aircrafts fluids, which can lead to extensive corrosion. ONE OF THE MOST IMPORTANT TOOLS FOR CORROSION PREVENTION AND CONTROL.

Sealants

What should you not do with the portable 15 & 45 gallon Foam Generating Cleaning Unit without releasing pressure?

Service it

What should you not do to Natural and Synthetic Rubber?

Shall not be Painted or oiled

Must be removed to facilitate inspection. They are usually the last items to. be inspected for corrosion damage.

Shock Mounts

Lubricant should be applied....

Sparingly to prevent accumulation of dust, dirt, and other foreign matter. Any excess should be wiped away.

Filiform Corrosion

Special form of oxygen concentration cell corrosion or crevice corrosion which occurs on metal surfaces having an organic coating system. Recognized by characteristic wormlike traces of corrosion products beneath the paint film.

The Environmental Protection Agency (EPA) has established specific requirements for using this method to be used on aircraft surfaces

Spray Painting

Corrosion

The electrochemical deterioration of a material or its properties due to its chemical reaction with the surrounding environment.

Solvent Vapor Drying

The fastest and most efficient means of drying. Uses Solvent Ultrasonic Cleaner to dry by means of evaporation. Drying time is usually 15 seconds to 3 minutes.

Forced Air Oven

The most efficient drying oven and be used to dry all types and sizes of equipment and components.

Human Eye

The most useful tool for detection of corrosion.

What must be done if the protective finish which covers the depleted Uranium is chipped, peeled, or otherwise removed so the dark gray or black depleted Uranium is visible?

The part must be returned to the licensee for rework or disposal.

What is the primary objective of the Paint System?

To protect all exposed surfaces against corrosion and any other forms of deterioration.

10X Magnifying Glass

Tool used to find and evaluate the extent of corrosion damage.

The most common type of corrosion.

Uniform Surface Corrosion

Circulating Air drying oven

Used to dry small electrical and electronic components, such as unpressurized instruments, control boxes, printed circuit boards and similar devices. Should NEVER be operated over 130F.

Detailed Inspection

Very effective fro detecting surface corrosion if done carefully and with the knowledge of where and what to look for.

What must you do for hot weather cleaning procedures above 80F?

Wet aircraft exteriors with fresh water before cleaning will cool surfaces and help prevent fast evaporation.

Moisture

What is the biggest contributor to corrosion in avionics?

Design Step

When is the best time to prevent corrosion?

Every 7 days

When should a Navy Aircraft be cleaned when aboard a ship?

Every 14 days

When should a Navy Aircraft be cleaned when ashore?

Daily cleaning of an aircraft is required when....

deployed within 3 miles of salt water or when flown below 3000 feet over salt water.

Sealant may be ______________ of their original shelf life after passing the required test.

one-half