7.18 Flashcards
What are the 2 main types of defects being looked for on disassembly?
Corrosion and metal fatigue.
What is an endoscope used for?
Inspection of interior structure or components.
What magnifying glass is usually used?
8x
What must damage be classified as?
Allowable
Non-allowable
What 5 methods of corrosion removal is there?
Abrasion by hand Wire brushing Grinding Rotary files Abrasive blasting
What corrosion removal method is recommended for heavy corrosion?
Rotary file.
What corrosion removal method is not recommended for internal corrosion?
Abrasive blasting.
What magnifying glass is recommended to inspect the removal of corrosion?
10x
How is corrosion on steel usually shown?
Putting, usually black in colour.
How is corrosion on titanium shown?
Black or white coloured oxide.
What process is similar to anodising but done with sulphuric acid?
Eloxadising.
What is the disadvantage of a eloxadising layer?
Cracks easily.
What are phosphate coatings used for?
Corrosion resistance, lubricity or foundation for coatings and paints.
What are the main types of phosphate coatings?
Manganese, iron and zinc.
What is CCC?
Chemical Conversion Coating.
What is a paint system?
Complete build up of all layers of a paint finish.
What paint systems do Airbus and Boeing use?
Airbus- 3 paint system
Boeing- 2 paint system
What does a wash primer act as in the interior structure?
Corrosion protection.
What does the FCR mean in Wash Primer FCR?
Filliform corrosion resistant.
When is an FCR primer not recommended?
Humidity more than 75%
Temps lower than 15 Celsius
What must wash primer FCR not be applied to steels with breaking strength more than?
180 KSI
What is the pot life time for intermediate primers after preparation?
6 hours at temps of 18-22 Celsius.
What does phosphoric acid cause in primers?
Hydrogen embrittlement
What is the pot life and cure times for epoxy resins?
4 hours.
24 hours at 18 Celsius.
What is the last paint layer applied?
Coating lacquer.
Where are all coating lacquers applied?
All outer cabin parts subject to weather conditions.
And interior parts which have contact with hydraulic oils and other aggressive fluids.
How much can a clear varnish increase age of a paint system?
25-50%
What are electrically conductive paints for?
Plastic parts.
Exception antennae covers
How many countersinks in composite components must be covered electrically inductive paint?
75%
What is the most common encountered water displacing inhibitor?
Dinitrol
Where are fillet seals applied?
Edges of structural joints.
Where are injection seals applied to?
Fill channels and holes that occur as a result of structural design.
What is a faying surface seal for?
Sandwiched between 2 fastened mating parts.
Recommended thickness 0.005-0.015 inch thickness
What are prepack seals for?
Fill structural cavities that are enclosed after assembly.
What is a seal plane?
The structural boundary on which the continuity of seal is established.
What 2 categories are sealants divided into?
Silicon and non-silicon.
What are silicon compounds?
Usually white, red or grey in colour.
Where heat resistance is required.
Where are non silicon sealants used?
Where heat resistance is not required.
What is the classification for sealants?
Class A- Brush coat Class B- Filleting Class C- Faying surface Class D- Hole-filling Class E&F- Sprayable
What will happen to a sealant if temps are over 120 Fahrenheit.
Bubbling will occur.
What do uncured silicons absorb?
CO2
What is the only method of sealing that prevents fuel leakage in fuel tanks?
Fillet.
What is used to seal fasteners within fuel tanks?
Metal seal caps.
Must 2 part sealants be completely mixed?
Yes.
Streaked appearance evidence of incorrect mixing
What temperature are mixed sealants stored at?
Maximum -40 Fahrenheit
What does a vacuum cleaner do?
Removes aluminium swarf and other debris from areas ready to be sealed?
What is the most commonly used solvent for cleaning structures prior to sealing?
MEK
