7.18 Inspection & Repair Techniques Flashcards
1
Q
A
2
Q
Why are thorough and repeated inspections necessary in repairing structural damage?
A
To ensure the aircraft is maintained to the highest possible condition and to prevent gradual deterioration of airworthiness.
3
Q
What are the classifications of damage?
A
- Allowable Damage
- Non-Allowable Damage
- Non-Repairable Damage
4
Q
What should be done to prepare for a thorough inspection?
A
Ensure all required panels, access doors, fairings, and cowlings are opened or removed and the structure is thoroughly cleaned.
5
Q
What is a typical checklist for a general inspection of an aircraft?
A
- Fuselage and hull
- Systems and components
- Cabin and flight deck
- Engine and nacelle
- Landing gear
- Wing and centre section
- Empennage
- Propeller
- Communication and navigation
- Miscellaneous items (emergency and first aid equipment)
6
Q
What types of tools are used for inspection?
A
- Inspection mirrors
- Magnifying glasses
- Borescopes
7
Q
What is the definition of ‘damage’ according to the Structure Repair Manual (SRM)?
A
A cross-sectional area or a permanent distortion of a structural member.
8
Q
What is the difference between a defect and damage?
A
A defect is any event or condition which reduces the serviceability of the aircraft, while damage refers specifically to physical harm.
9
Q
Fill in the blank: A _______ is a damaged area that is the result of scuffing, rubbing, scraping, or another type of surface erosion.
A
Abrasion
10
Q
What is corrosion?
A
Damage that results from complex electro-chemical action and gives a cross-sectional area change.
11
Q
What is a crack in terms of aircraft damage?
A
A partial fracture or a full break in the material that causes a significant cross-sectional area change.
12
Q
Explain what a dent is.
A
A damaged area that is pushed in from its contour with no change in the cross-sectional area of the material.
13
Q
What constitutes non-repairable damage?
A
Damage to structural components which cannot be repaired, requiring replacement of the complete component.
14
Q
What is the purpose of a visual inspection system?
A
To ensure that the aircraft is maintained to the highest possible condition.
15
Q
What does allowable damage mean?
A
Damage that is slight or of little significance and unlikely to propagate further damage.
16
Q
True or False: Non-Allowable Damage requires repair by removing the damaged area and inserting a reinforcing piece.
A
True
17
Q
What are Non-Destructive Inspection methods (NDI) used for?
A
To inspect damaged areas for defects such as corrosion, pitting, and heat/stress cracks.
18
Q
What is the function of inspection mirrors?
A
To provide a full view behind flanges and brackets during inspections.
19
Q
What magnification is most commonly used with magnifying glasses during inspections?
A
2x
20
Q
What is a borescope?
A
An optical instrument used for the inspection of the internal structure or components of an aircraft.
21
Q
Name a feature of borescopes that assists in documentation during inspections.
A
Ability to attach a camera for taking photographs of the area under inspection.
22
Q
Fill in the blank: A _______ is a damaged area caused by a sharp object that results in a continuous groove in the material.
A
Gouge
23
Q
What should be considered when evaluating damage during an inspection?
A
Type of damage, type of original material, location of the damage, type of repair required, tools and equipment available.
24
Q
What is the purpose of surface preparation before corrosion removal?
A
To protect adjacent areas/equipment against the effects of chemicals and cleaning agents
Use suitable masking paper and tape.
25
List the metals for which corrosion removal procedures are explained.
* Ferrous
* Aluminium
* Magnesium
* Titanium
26
What are the common visual signs of corrosion on a painted surface?
* Scaly or blistered surface
* Change of colour
* Blisters in the paint
27
What must be done immediately when corrosion is found?
All corrosion must be completely removed.
28
What are some corrosion preventive maintenance actions?
* Adequate cleaning
* Thorough periodic lubrication
* Detailed inspection for corrosion
* Prompt treatment of corrosion
* Drain holes free of obstructions
* Daily draining of fuel sumps
* Daily wipe down of exposed critical areas
* Sealing of aircraft against water
* Maximum use of protective covers on parked aircraft
29
True or False: Corrosion that remains can cause new corrosion.
True
30
What is the recommended equipment for a visual inspection for corrosion?
* Magnifying glass
* Mirrors
* Borescopes
* Fibre optics
31
What is the first step in the corrosion removal process?
Cleaning and stripping of the corroded area.
32
Fill in the blank: Abrasion by hand is suitable for areas of _____ corrosion.
light
33
What is wire brushing used for?
To remove heavy corrosion and embedded paint or dirt.
34
Why should wire brushing not be used on aluminium parts?
Fine particles from the brush can embed in the aluminium and cause further corrosion.
35
What is the procedure for grinding corrosion?
* Remove corrosion by grinding until a firm corrosion-free surface is achieved
* Polish the surface with fine abrasive paper
36
What is abrasive blasting used for?
To clean or finish metal surfaces by bombarding them with abrasive particles.
37
What PPE is required when using abrasive blasting?
* Respirator
* Hearing protection
* Eye and head protection
* Leather gloves
* Safety shoes or boots
38
What is the purpose of neutralisation in corrosion removal?
To complete the corrosion removal where deep corrosion was found on aluminium alloys.
39
Describe the chromic acid inhibitor solution.
A 10% solution by weight of chromic acid, activated by sulfuric acid, effective for treating exposed or corroded aluminium surfaces.
40
What is the most common type of corrosion on carbon steel?
Ferrous oxide (rust)
41
What does phosphoric acid do in the context of corrosion removal?
It actively removes iron oxide without chemically etching the base metal.
42
Fill in the blank: To ensure safety, always read the _____ before using cleaning agents.
Material Safety Data Sheet (MSDS)
43
What happens if minor traces of corrosion are left?
They can act as a starting point for further corrosion.
44
What is the recommended method for deep cleaning aluminium surfaces?
Using a cleaner and brightener compound before polishing.
45
What are the three forms of serious corrosion attack on aluminium alloys?
* Penetrating pit type corrosion
* Stress corrosion cracking
* Intergranular corrosion
46
True or False: Chemical surface treatment chemicals can be mixed with any substance.
False
47
What is the most used rust removing chemical?
Phosphoric acid
## Footnote
Phosphoric acid is commonly utilized for rust removal due to its chemical properties.
48
True or False: Phosphoric acid is safe to handle without any protective gear.
False
## Footnote
Phosphoric acid is corrosive and highly toxic, requiring Personal Protective Equipment (PPE).
49
What should be done if there is spillage of phosphoric acid?
Collect any spillage and properly dispose of it
## Footnote
Proper disposal is crucial to ensure safety and compliance with regulations.
50
What happens when phosphoric acid is applied to rust?
It converts rust to a water-soluble compound that can be scrubbed/washed away
## Footnote
This reaction helps in effective rust removal.
51
What is necessary for treating steel parts in aircraft to prevent rust?
The steel part must be removed from the airframe for treatment
## Footnote
This is to ensure complete removal of rust residues.
52
What are stainless steel and nickel chromium alloys primarily used for?
Where corrosion resistance is a major consideration
## Footnote
These materials are selected for structural parts due to their corrosion-resistant properties.
53
What type of corrosion commonly appears on stainless steels?
Pitting, usually black in color
## Footnote
Pitting corrosion can compromise the integrity of stainless steel components.
54
What is a significant characteristic of titanium alloys?
Highly corrosion-resistant
## Footnote
Despite their resistance, titanium alloys can deteriorate due to salt deposits and impurities.
55
What should not be used for cleaning titanium parts?
Steel wool, iron scrapers, or steel brushes
## Footnote
These can damage the titanium surface.
56
What is the purpose of pre-treatments in corrosion protection?
To increase corrosion resistant properties and provide a good surface for paint adhesion
## Footnote
Pre-treatments are crucial for long-term protection against corrosion.
57
Fill in the blank: A sacrificial corrosion prevention layer has a _______ electrolytical potential than the main metal.
lower
## Footnote
This allows the sacrificial layer to corrode first, protecting the underlying metal.
58
What is anodising?
A method of treating metals to form oxide coatings that enhance surface performance
## Footnote
Anodising increases wear and corrosion resistance of metals.
59
What is the primary electrolyte used in the anodising process for aluminium?
Sulphuric acid
## Footnote
Sulphuric acid is commonly used for anodising due to its effectiveness.
60
True or False: Eloxadising creates a flexible layer on the surface of metals.
False
## Footnote
Eloxation layers are hard and brittle, making them prone to cracking.
61
What are the three layers in the Airbus paint system for the outer fuselage skin?
* Wash Primer
* Paint Primer
* Coating Lacquer
## Footnote
This multi-layer system provides both adhesion and protection against corrosion.
62
What is the function of the Wash-Primer FCR?
Acts as corrosion protection and improves adhesion of the paint system
## Footnote
It consists of phosphoric acid and zinc-chromate pigments.
63
What should be checked when inspecting paint finishes?
* General condition
* Surface polish
* Brittleness
* Cracks
* Colour change
* Satisfactory adhesion
* Separation due to chemicals
## Footnote
A thorough inspection helps identify underlying corrosion issues.
64
What is the risk of not observing the minimum cure time for the FCR primer?
Impaired corrosion protection and adhesion
## Footnote
Proper curing time is essential for effective performance of the primer.
65
What is the minimum cure time importance in a three-layer paint system?
If the minimum cure time is not observed before the next coat, corrosion protection and adhesion are impaired.
66
Under what conditions is the use of FCR primer not recommended?
Humidity higher than 75% or temperatures below 15 °C.
67
What must be applied after the FCR primer?
Aerodur S15/90 or CF Primer 37047.
68
What is the maximum breaking strength for applying Wash-Primer FCR?
180 KSI (1240 N/mm²).
69
What is the pot lifetime after preparation for the intermediate primer?
6 hours at temperatures of 18-22 °C.
70
What is the depth hardening time for the intermediate primer?
About four hours (can be shortened by heating up to 125 °C).
71
What is the cure time for Epoxy Primer at 18 °C?
24 hours.
72
Which products are commonly used as coating lacquers?
* Sikkens (C21/100 or HF-High Flexible)
* Cellomer
* Finsh
* De Soto
* ICI
73
What is the purpose of applying a clear varnish over coating lacquers?
To protect against general aging and decay and increase lifespan by 25-50%.
74
What type of paint is used for plastic components in aviation?
Electrically conductive paints or antistatic primers.
75
What is required to achieve sufficient conductivity with electrically conductive paint?
A minimum of 75% of all countersinks in composite components must be covered.
76
What are water-displacing inhibitors used for?
* Stop corrosion that has already started
* Make surfaces water-repellent
* Enhance corrosion protection.
77
Name two water-displacing inhibitors available in aviation.
* LPS 3
* Boeshield T9 H5
78
What are the safety precautions for using Dinitrol products?
* Ensure proper ventilation
* Wear Personal Protective Equipment (PPE)
* Keep away from heat and ignition sources.
79
What is the thickness of the dry film built up by Dinitrol AV 8?
About 1 - 2 mm (0.3 in).
80
What characterizes Dinitrol AV 30?
A thixotropic, elastic film that does not crack when deformed.
81
What is the cure time for Dinitrol AV 100?
About six hours.
82
True or False: Epoxy Primers can contain phosphoric acid.
False.
83
Fill in the blank: The coating lacquer is applied as the last layer on previously applied _______.
[wash primers and intermediate primers]
84
What are the most important steps in repairing structural damage?
Inspection of damage and an accurate estimate of repair
85
Why is it necessary to perform an extensive inspection of the structure when investigating damage?
To ensure all damage is identified and assessed
86
What does the Structural Repair Manual (SRM) encompass?
Nearly every repair to any part of the airframe deemed appropriate by the manufacturer
87
What is the primary objective of an aircraft repair?
To restore damaged parts as close to their original condition as possible
88
What are the two classifications of aircraft structure?
* Primary structure
* Secondary structure
89
What is a primary structure in an aircraft?
A critical load bearing structure that is essential for flight
90
What are examples of primary structures?
* Fuselage
* Wings
* Stabilisers
* Flight control surfaces
* Landing gear
91
What is a secondary structure in an aircraft?
A structural element that enhances aerodynamics but does not lead to loss of the aircraft if failed
92
What are the classifications of repairs in the SRM?
* Category A, B, or C repairs
* Permanent, Interim, or Time-Limited Repairs
93
What characterizes a Category A repair?
A permanent repair with sufficient inspections from the Zonal Inspection
94
What is a Category C repair?
A time-limited repair requiring supplemental inspections and replacement after a specified time limit
95
What defines a Permanent Repair?
A repair requiring no action other than operator maintenance
96
What is an Interim Repair?
A repair that can remain indefinitely but must be inspected and replaced if deterioration occurs
97
What is a Time-Limited Repair?
A repair that must be replaced after a specified time due to insufficient durability
98
What is an external repair?
A repair that is applied quickly and typically protrudes from the aerodynamic surface
99
What is a flush repair?
A repair that is flush with the aerodynamic surface, usually performed in a workshop
100
What does the Structural Repair Manual (SRM) include?
* Structural damage criteria
* Structure material identification
* Typical repairs
* Substitute materials
* Fastener information
101
What is the purpose of the SRM?
To provide specific instructions and data related to the repair of the aircraft structure
102
What are the chapter headings in the SRM?
* Chapter 51: Structures - General
* Chapter 52: Doors
* Chapter 53: Fuselage
* Chapter 54: Nacelles/Pylons
* Chapter 55: Stabilisers
* Chapter 56: Windows
* Chapter 57: Wings
103
How is the SRM organized?
By chapters and sections, with each section covering specific components of the aircraft
104
What does Chapter 51 of the SRM cover?
General subjects related to the entire structure of the aircraft
105
What is the numbering format for SRM chapters and sections?
A three-element system: chapter, section, and subject number
106
What should be considered if a typical repair is not found in the SRM?
* General repair practices in chapter 51
* Preparing a specific repair design
* Replacing the damaged part
107
What is the first step in using the SRM for a repair?
Check for allowable damage limits in the applicable table of contents
108
Why do older aircraft require special attention in maintaining their airframe?
Older aircraft are susceptible to failure due to corrosion and fatigue, requiring deeper inspections to ensure airworthiness.
109
What is the purpose of the National Ageing Aircraft Research Programme?
To study how age affects aircraft and develop plans to maintain airworthiness.
110
Identify corrosion-prone areas on an aircraft.
* Aircraft galleys and lavatories
* Battery compartments
* Landing gear and wheel well areas
* Bilge areas
111
Differentiate between the different levels of damage in aircraft.
* Corrosion damage
* Fatigue damage
* Accidental damage
112
Explain the structural design approaches of Safe-Life.
Safe-life specifies a 'safe' lifespan within which there is no significant risk of structural failure; components must be replaced before reaching this lifespan.
113
What is the Fail-Safe design principle?
Fail-Safe structures can sustain limit loads even when one element fails, using backup structures and secondary load paths.
114
What does Damage Tolerance mean in aircraft design?
Damage tolerance allows cracks to develop but ensures they can be detected before causing catastrophic failure.
115
Fill in the blank: Corrosion damage is caused by the process of _______.
corrosion or oxidation.
116
True or False: Fatigue damage is time-dependent.
False. Fatigue damage relates to the number of aircraft cycles, not time.
117
What are the three kinds of damage that lead to aircraft failure?
* Corrosion damage
* Fatigue damage
* Accidental damage
118
What factors contribute to corrosion in aircraft?
* Air pollution
* Type of metal
* Type of stress on the metal
* Presence of water and oxygen
119
List some methods used for corrosion removal.
* Chemical
* Mechanical
120
What is the primary threat to the structure of an aircraft?
Corrosion.
121
What is the significance of the Aloha Airlines flight incident?
It highlighted the need for thorough inspection and maintenance of older aircraft due to structural failure from fatigue.
122
What is the critical crack length in fatigue analysis?
The length at which a fracture can occur.
123
Explain the importance of the Corrosion Prevention and Control Programme (CPCP).
CPCP aims to prevent corrosion through regular inspections and treatments, reducing fatigue-related failures.
124
Fill in the blank: Fatigue occurs through _______ loading patterns.
cyclic.
125
What types of aircraft operations increase fatigue rates?
* Aerobatics flying
* Aerial mustering
* Aerial agriculture
126
What is a major contributing factor to the Aloha flight 243 accident?
The average flight duration of the aircraft was just 25 minutes, leading to more pressurisation cycles.
127
What materials can be affected by fatigue?
Primarily metal components, but also non-metallic materials.
128
What inspection methods are effective in detecting corrosion damage?
* Dye penetrant
* Eddy current
* Ultrasonic
* Radiographic inspections
129
What are the two primary areas the FAA divided aircraft into for analysis?
* Structures
* Electrical systems
130
What is the effect of operating aircraft near the ocean on corrosion?
Increased electrolyte action of water due to salt accelerates corrosion.
131
True or False: The fail-safe principle assumes an initial crack in aircraft design.
False. Damage tolerance assumes an initial crack, while fail-safe does not.
132
What is the function of a safety by inspection approach in aircraft design?
To detect cracks before they affect flight safety.
133
What areas of concern should be inspected for magnesium wheels?
Presence of entrapped water or its effects around bolt heads, lugs, and wheel-web areas
## Footnote
Magnesium wheels are prone to issues related to moisture retention, which can lead to corrosion.
134
What specific areas of exposed rigid tubing require inspection?
B-nuts, ferrules, under clamps, and tubing identification tapes
## Footnote
These areas are prone to wear and can accumulate moisture.
135
What are common traps for water and debris in aircraft structures?
Crevices between stiffeners, ribs, and lower skin surfaces
## Footnote
These areas can lead to corrosion if moisture is retained.
136
How does corrosion occur in a metal skin joined by spot welding?
Trapped corrosive agents between the layers of metal lead to corrosion, evidenced by corrosion at crevices
## Footnote
Spot welding can create hidden areas where moisture accumulates.
137
What is the best prevention method for corrosion in aircraft structures?
Keep potential moisture entry points filled with a sealant or a suitable preservative compound
## Footnote
This includes seams and holes from broken spot welds.
138
Why is inspecting fuel tanks challenging?
Fuel tanks are located inside wing and fuselage structures, making access difficult
## Footnote
Internal inspection often requires emptying the tanks.
139
What is a common issue in aircraft fuel tanks?
Bacterial growth
## Footnote
This growth can be controlled with growth-inhibiting additives during refueling.
140
What part of aircraft panels is particularly susceptible to corrosion?
Piano hinges due to dissimilar metal contact between steel pin and aluminium hinge
## Footnote
They also trap dirt, salt, or moisture.
141
What should be included in the inspection of wing flaps and spoiler recesses?
Scheduled inspections due to accumulation of grease, dirt, and water
## Footnote
These areas are often overlooked when the flaps and spoilers are retracted.
142
What materials are reciprocating engine mounts primarily made of?
Welded tubular steel
## Footnote
These mounts require regular inspection for corrosion and fatigue due to engine stresses.
143
What is the recommended inspection method for corroded tubing?
Clean the tubing and test structural integrity using eddy current and ultrasonic inspections
## Footnote
This helps prevent recurring corrosion.
144
How should wire control cables be inspected?
Inspect for corrosion by random cleaning with solvent-soaked cloths
## Footnote
Cables with internal corrosion must be replaced.
145
How can light external corrosion on cables be treated?
Remove with a stainless steel wire brush and re-coat with a recommended preservative
## Footnote
Regular maintenance helps ensure cable integrity.
146
What should be regularly inspected in electronic and electrical compartments?
Circuit breakers, contact points, and switches for moisture and corrosive attack
## Footnote
Component removal may be necessary for thorough inspection.
147
What does NDI stand for?
Non-destructive Inspection
148
What does NDT stand for?
Non-destructive Testing
149
What is the primary purpose of NDI/NDT?
To determine the airworthiness of a component without causing further damage.
150
List three common non-destructive inspection methods.
* Visual inspection
* Ultrasonic
* Radiography
151
What is a discontinuity in NDI/NDT terms?
An interruption in the normal physical structure or configuration of a part.
152
Define 'defect' in the context of NDI/NDT.
A discontinuity that interferes with the usefulness of a part.
153
What is an imperfection?
A departure of a quality characteristic from its intended condition.
154
True or False: A flaw is always harmful.
False
155
What are the advantages of visual inspection?
* Inexpensive
* Highly portable
* Immediate results
* Minimum training
* Minimum part preparation
156
What is a major disadvantage of visual inspection?
Generally only detects large discontinuities.
157
What material types can dye penetrant inspection be used on?
* Aluminium
* Magnesium
* Cast iron
* Stainless steel
* Titanium
* Ceramics
* Plastics
* Glass
158
What is required for a successful dye penetrant inspection?
The defect must be open to the surface.
159
What is the basic process for conducting a dye penetrant inspection?
* Thorough cleaning of the metal surface
* Applying penetrant
* Removing penetrant
* Drying the part
* Applying the developer
* Inspecting and interpreting results
160
What is the significance of the developer in dye penetrant inspection?
It dries to a smooth, even white coating and reveals defects as bright red indications.
161
What can cause false indications in dye penetrant inspection?
* Poor washing
* Press-fit parts
162
What are mandatory safety precautions when using dye penetrants?
* Adequate ventilation
* Wear eye protection, gloves, and overalls
* Avoid looking directly into the ultraviolet lamp
* Dispose of aerosol cans correctly
163
What is the principle behind eddy current inspection?
Inducing eddy currents in a conductive material and measuring changes in impedance.
164
List some applications of eddy current inspection in aircraft maintenance.
* Inspecting engines
* Shafts
* Wing skins
* Wheels
* Bolt holes
165
What does an eddy current test instrument do?
* Generates an AC signal
* Receives signals from the test coil
* Displays the results
166
Fill in the blank: The _______ method is used to detect surface cracks and corrosion.
[eddy current]
167
What is a major disadvantage of X-ray radiography?
It is very expensive and a safety hazard.
168
True or False: Ultrasonic inspection requires significant part preparation.
False
169
What is the role of a borescope in NDI?
It allows inspection of areas that cannot be accessed without disassembly.
170
What types of materials can be inspected using penetrant dye?
* Non-porous materials
* Metals
* Ceramics
* Plastics
* Glass
171
What is the advantage of using a fluorescent dye penetrant?
Defects show up as a brilliant yellow/green color under black light.
172
What does the term 'magnetic particle' refer to in NDI?
A method that detects surface and subsurface imperfections in ferro-magnetic materials.
173
What are the three basic functions of an instrument in testing?
Generating, Receiving, Displaying
174
What is required for the calibration of eddy current test equipment?
A reference standard made from the same material as the item to be tested
175
What typical defects can be found using Eddy Current Testing?
176
What is the ultrasonic inspection method?
An NDI technique that uses sound energy moving through the test specimen to detect flaws
177
What displays can be used for ultrasonic testing results?
Cathode Ray Tube (CRT), Liquid Crystal Display (LCD), computer data program, video/camera medium
178
What are the three types of display patterns in ultrasonic testing?
'A-scan', 'B-scan', 'C-scan'
179
What are the two basic methods used in ultrasonic inspection?
* Immersion test
* Contact testing
180
What are the three basic ultrasonic inspection methods?
* Pulse echo
* Through transmission
* Resonance
181
What does radiographic inspection use to identify defects?
X-ray and gamma-ray radiation
182
What is produced when penetrating radiation is projected through a part in radiographic inspection?
An invisible or latent image in the film
183
What are the three major steps in the X-ray process?
* Exposure to radiation
* Processing of the film
* Interpretation of the radiograph
184
What factors need to be considered for radiographic exposure?
* Material thickness and density
* Shape and size of the object
* Type of defect to be detected
* Characteristics of the X-ray machine
* Exposure distances
* Exposure angles
* Film characteristics
* Type of the intensifying screen, if used
185
True or False: Only qualified radiographers are allowed to operate X-ray units.
True
186
What are some dangers associated with radiation from X-ray units?
* Blood and intestinal disorders
* Leukaemia
* Other cancers
* Skin damage
* Hair loss
187
What is the Magnetic Particle Inspection (MPI) method used for?
Detection of surface and near-surface flaws in magnetic materials
188
How is the part magnetised in Magnetic Particle Inspection?
Either locally or overall
189
What causes local magnetic flux leakage in MPI?
A surface flaw distorting the magnetic field
190
What methods can be used to produce magnetisation in MPI?
* Applying a permanent magnet or electromagnet
* Passing a large current through the specimen
* Using a current-carrying coil
* Making the specimen the secondary loop of a transformer
* Placing a current-carrying coil close to the specimen surface
* Threading a current-carrying bar through a hollow specimen
191
Fill in the blank: The method of magnetisation in MPI must produce a magnetic field with lines of force at a large angle to the expected direction of the _______.
cracks to be detected
192
What type of current can be used for magnetisation in MPI?
DC or AC of any waveform
193
What is the advantage of using fluorescent particles in MPI?
Requires UV-A illumination for better visibility of cracks
194
What can impair flaw sensitivity in MPI?
Applying methods to relatively rough and dirty surfaces
195
What can happen if an aircraft is disassembled and reassembled incorrectly?
Significant damage can be incurred.
196
Why is it important to follow basic aircraft maintenance hangar etiquette?
To ensure safety and organization in the maintenance area.
197
What occurs during the disassembly and reassembly of major components?
Components are removed, inspected, and reinstalled as per the maintenance manual.
198
What happens during the disassembly and reassembly of minor components?
Minor components are serviced or replaced as needed, often following their specific Aircraft Maintenance Manual.
199
What is the process for inserting and removing solid rivets?
Select rivet, prepare hole, insert rivet, and form upset head.
200
What are the two types of blind rivets?
Rivets and bolts.
201
What is the purpose of structural sealing in aircraft maintenance?
To protect components from environmental factors and maintain structural integrity.
202
What are the types of commonly used sealants?
* Silicone
* Polyurethane
* Butyl
* Epoxy
203
What is essential to do before starting any maintenance task?
Ensure all correct tooling, parts, servicing fluids, and support equipment are available.
204
What must be done to components removed during maintenance?
Label and store them in a safe place.
205
True or False: Maintenance manuals contain the approved methods of disassembly and reassembly.
True
206
What should be done with 'Do Not Operate' tags during maintenance?
They must be placed on controls and switches being serviced.
207
What types of components require maintenance checks?
* Engines
* Propellers
* Landing gears
* Wheels
208
What is the significance of torque values in assembly?
They ensure proper fastening according to the manufacturer's specifications.
209
What is a jig used for in aircraft assembly?
To ensure high dimensional accuracy during the assembly of components.
210
What items are typically discarded after removal?
* Filters
* Sealing rings
* Fuels
* Oils
211
What common issue may occur when dismantling parts?
Encountering a seized fastener.
212
What is the recommended action for removing a seized fastener?
Use penetrating oil, heat, or cold to assist in removal.
213
What materials are solid rivets primarily made from?
* Aluminium
* Steel
* Titanium
* Monel
214
Fill in the blank: The upset head of a rivet is formed by the _______ of the shank.
[deformation]
215
What must be checked after installing rivets?
Ensure the joint is tight and rivets are fully seated and correctly formed.
216
What does the term 'On-Condition' refer to?
Components that are removed only when they fail.
217
What do special fasteners require when used in CFRP structures?
Special nuts or collars.
218
What is a Fastener Dipping Gauge used for?
To ensure the correct length of rivets.
219
What is the acceptable condition for the head of a countersunk rivet?
It should be level with or slightly above the surface of the material.
220
What can cause deformation or buckling of metal sheets during riveting?
* Too much tool pressure
* Rivets expanded between the sheets
* Trapped foreign material
221
What is permitted regarding the eccentricity of the upset head of a rivet?
Eccentricity of the upset head is permitted if the rivet shank cannot be seen.
222
What is the acceptable limit for malformation of the upset head?
Malformation is permitted if the shape is within the dimension limits given in upset rivet dimension tables.
223
Are cracks allowed in the upset head of aluminium alloy 2017 and 2024 rivets?
Cracks are permitted within given limits.
224
Are cracks in the upset head of other aluminium alloy rivets permitted?
No, cracks in the upset head of other aluminium alloy rivets are not permitted.
225
What type of cracks are not permitted in the structure material under either head?
Cracks are not permitted.
226
True or False: Cracks in the heads of titanium and Monel rivets are permitted.
False.
227
What is one of the main sources of structural fatigue and failure?
Fastener holes.
228
What should be preserved when removing a rivet?
The rivet hole’s original size and shape.
229
What tools can be used to remove rivets?
Hand tools, a power drill, or a combination of both.
230
What should be used to support thin metal or unsupported structures during rivet removal?
A back-up block.
231
What safety equipment should be worn during rivet removal operations?
Eye protection and any other Personal Protection Equipment (PPE).
232
What is a critical step to take before drilling into a rivet head?
Centre-punch the head as a guide for the drill-bit.
233
What must be done if the rivet shank is unusually tight after the head is removed?
Drill the rivet about two-thirds through the thickness of the material.
234
What should be inspected after removing a rivet?
The hole for any signs of damage.
235
What is the procedure for removing countersunk rivets?
Drill into the exact centre of the rivet head to the approximate depth of the head.
236
Fill in the blank: Replace rivets with some of the same size and ______ whenever possible.
[strength]
237
What is the main characteristic of blind rivets?
Installed with access to only one end.
238
Name two standard forms of blind rivets.
* Friction Lock
* Mechanical Lock
239
What is a key feature of friction lock rivets?
The stem is pulled until the header forms a tail (bulb) on the blind side.
240
True or False: A friction lock rivet can replace a solid shank rivet size for size.
False.
241
Name one type of mechanical lock rivet.
* Huck-Loks®
* Cherrylocks®
* Olympic-Loks®
* Cherrymax®
242
What is a disadvantage of mechanical lock rivets?
If a rivet is too short, the lock ring can set prematurely.
243
What is sealing in the context of aircraft manufacture?
A process that confines liquids and gasses within a given area or prevents them from entering areas.
244
What are the four levels of sealing?
* Absolute
* Extensive
* Intermediate
* Limited
245
What types of areas require sealants?
* Fuel Areas
* Pressurised Areas
* Environmental Areas
* Corrosion Areas
* Electrical Areas
* Firewall Areas
* Acid Areas
246
What are most sealing compounds known chemically as?
Polysulfides.
247
What is the main advantage of the Hi-Lite fastener?
Excellent strength to weight ratio.
248
What is the first step in the removal process of a Hi-Lok fastener?
Remove the collar using dedicated tools.
249
What should be avoided when removing a Hi-Lok fastener?
Using a chisel and hammer.
250
What are the two main categories of sealing compounds?
Silicone and non-silicone
251
What colors are silicone compounds typically available in?
White, red, or grey
252
What is the typical color of non-silicone compounds?
Any color
253
What is Class A sealant defined as?
Brush coat sealant thinned with solvent for suitable viscosity
254
What class of sealant is characterized as a filleting sealant?
Class B
255
Define Class C sealant.
Faying surface sealant with medium consistency for good spreadability
256
What does Class D sealant refer to?
Hole-filling sealant with very low slump
257
What are Classes E and F used for?
Sprayable sealants
258
What is the maximum differential pressure that sealants must withstand?
Approximately 11 lb/in2 (0.758 bar)
259
What is the operating temperature range for sealants?
-65°F (-54°C) to 160°F (71°C)
260
What does application time refer to?
Time in hours after thawing during which the sealant can be extruded
261
How is squeeze-out life defined?
Time in hours after thawing during which a faying surface sealant can be squeezed out
262
What is tack-free time?
Time in hours after thawing required for the sealant to cure sufficiently
263
What does cure time signify?
Time in hours after thawing required for the sealant to cure firmly enough to handle
264
What can retard the curing of two-part materials?
Temperatures below 60 °F (15 °C) and/or relative humidity below 40%
265
What occurs if the temperature of the sealant exceeds 120 °F (49 °C)?
Bubbling will occur
266
What is a critical precaution for uncured silicones?
They must be protected from contact with CO2 sources
267
What should be done to ensure proper sealing preparation?
Thorough cleaning of the area
268
What is the purpose of preliminary cleaning?
Remove swarf, shavings, and other loose materials
269
What should be used for final cleaning before sealing?
Dampen clean wiping material with solvent
270
What is the role of a vacuum cleaner in the cleaning process?
To remove aluminium swarf and debris
271
How should two-part sealants be mixed?
Completely mixed to ensure uniform color and performance
272
What is the recommended method for mixing most sealants?
Machine mixing
273
What is the importance of thawing sealant to room temperature?
Cold sealant will not adhere properly
274
What tools are used for the removal and cutting of sealants?
Sealant removal or cutting tools made of hardwood or soft metal
275
What is the primary application tool for sealants?
Sealant gun
276
What feature do nozzles for sealants provide?
Available in assorted sizes and shapes for various sealing requirements
277
What type of rollers are recommended for spreading sealants?
Rubber rollers of approximately 50 Shore 'A' durometer hardness
278
What should be done if contact with sealant occurs?
Remove the sealant and thoroughly wash the affected area
279
Fill in the blank: The application time for Class B-2 sealant is ______ hours.
2
280
Fill in the blank: Squeeze-out life for Class C-20 sealant is a minimum of ______ hours.
20
281
True or False: Silicones can be stored with other sealants without risk of contamination.
False
282
What safety equipment should be worn when handling sealants?
Personal Protective Equipment (PPE)
283
What is the maximum allowable cure time for most sealants?
Given in the process specification
284
What is the purpose of multiple-orifice nozzles in sealant application?
To provide a more convenient angle or diameter for application of the sealant
## Footnote
They allow for more rapid spreading of sealant over large areas for faying surface sealing.
285
What type of rollers are recommended for spreading sealants?
Rubber rollers of approximately 50 Shore 'A' durometer hardness
## Footnote
These rollers are superior in spreading sealant and keeping it out of fastener holes.
286
What is the function of plastic scrapers in sealant application?
To spread sealant over a surface in situations where using a roller would be awkward
## Footnote
They are useful for access or other considerations.
287
What is a fillet seal?
A seal applied at the edges of structural joints, consisting of beads of sealant that adhere to both sides of the seam
## Footnote
Fillet seals provide maximum protection from fluid leakage.
288
What must be avoided during the working of a fillet seal?
Folds, flaps, and entrapped air
## Footnote
Air bubbles must be worked out to ensure a proper seal.
289
How is an injection seal applied?
To fill channels and holes resulting from structural design
## Footnote
Often used to back up a fillet seal.
290
What is a faying surface seal?
A seal consisting of a layer of sealant sandwiched between two fastened mating surfaces
## Footnote
Primarily used to prevent corrosion and facilitate leak tracing in fuel tanks.
291
What is the recommended thickness for faying surface sealant application?
A thickness that completely masks the surface yet minimizes the size of the continuous bead required
## Footnote
The specific range can be found in the SRM.
292
What is the purpose of an aerodynamic smoother in aircraft sealing?
To fill skin gaps and fair surface discontinuities for an aerodynamically smooth surface
## Footnote
It also helps to exclude water.
293
What is the seal plane?
The structural boundary on which the continuity of seal is established
## Footnote
In integral fuel tanks, it consists of structural components, fasteners, and sealant.
294
What are prepack seals used for?
To fill structural cavities that are enclosed after assembly and cannot be properly injected
## Footnote
They are commonly used in large structural fittings.
295
True or False: Fillet sealing is the basic method used for fuel retention within integral fuel tanks.
True
## Footnote
It is the only method that provides a reliable barrier against fuel leakage.
296
What is the first step in the three-phase system for sealing an integral fuel tank?
Apply a brush coat/precoat
## Footnote
This is followed by applying a small first fillet and then a full-size final fillet.
297
What is the purpose of metal seal caps in fuel tank fastener sealing?
To prevent leakage by fitting over the protruding end of the fastener
## Footnote
They are lightweight aluminum shells.
298
Fill in the blank: The sealant must be _______ continuously around the bottom of the seal cap.
extruded
## Footnote
This ensures proper sealing of the fastener.
299
What method is used for sealing electrical fittings?
Fillet seal
## Footnote
Each wire in a bundle is coated with the specified sealant prior to installation.
300
What is the purpose of maintenance documents/manuals in aircraft maintenance?
To assist the engineer with all maintenance when performing scheduled and unscheduled maintenance.
301
Name three examples of scheduled maintenance work.
* Aircraft turn around
* Daily checks
* Planned checks
302
What are two key documents that help engineers perform scheduled maintenance?
* Maintenance Planning Data (MPD) Document
* Aircraft Maintenance Manual (AMM)
303
List four examples of unscheduled maintenance work.
* Flight faults
* Ground faults
* Service problems
* Structural damage
304
Which documents assist engineers with unscheduled maintenance?
* Fault Reporting Manual (FRM)
* Maintenance Tips
* Fault Isolation Manual (FIM)
* Structural Repair Manual (SRM)
* Dispatch Deviations Guide (DDG)
* Aircraft Maintenance Manual (AMM)
305
What is the logical process that manuals guide aircraft engineers through?
Finding a diagnosis to ascertain the defect and the rectification action to follow.
306
What are the recommended troubleshooting steps?
* Identify the defect
* Conduct a visual inspection
* Conduct an operational check
* Classify the defect
* Locate and isolate the defect
* Rectify the defect
* Perform a final operational check
307
How should defects be recorded?
All defects must be transferred to a written record.
308
What can initiate the troubleshooting process?
* Discussing the defect with the person who identified it
* Checking previous technical entries in the technical logbook
309
What must be included in a thorough visual inspection?
* Evidence of improper installation
* Material condition
* Leaks
* Looseness
* Security
310
What is the purpose of an operational check?
To replicate the defect and check for external leakages, correct component movement, and timing.
311
What are the four basic categories of system operational malfunctions?
* Mechanical
* Hydraulic
* Pneumatic
* Electrical
312
What are common causes of hydraulic defects?
* External and internal leakages
* Total or partial restriction
* Improper lubrication
313
True or False: Electrical malfunctions can include power failures and wiring faults.
True
314
What is a common issue in pneumatic systems?
Low pressure and vacuum system faults, especially leaks.
315
What skills are required for locating and isolating defects?
* Hands-on practical experience
* Understanding of basic aircraft system theory
* Knowledge of aircraft systems operation
316
How are malfunctions typically rectified?
* Component replacement
* Rigging adjustments
* Bleeding the associated system
317
What must be done after completing any system maintenance?
Conduct a final operational check and perform an independent inspection.
318
Who is responsible for signing the Certificate of Release to Service (CRS)?
The appropriate licensed or certified engineer.
319
Fill in the blank: Defects occur through '_______' and '_______'.
[cause], [effect]
320
What should be checked and recorded after satisfactory completion of functional testing?
All associated paperwork, including new parts installed (part and serial numbers).
