11.2 A. Airframe Structures - General Concepts Flashcards by John Watts

What does PSE stand for?
A. Principal Safety Element
B. Pressurised Structural Equipment
C. Principal Structural Element

C. Principal Structural Element

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What does “Principal Structural Element (PSE)” refer to?
A. A part of the aircraft used mainly for comfort and design
B. A part of the aircraft that contributes significantly to carrying flight, ground, or cabin pressurisation loads, and whose integrity is essential in maintaining the overall structural integrity of the aircraft
C. A part of the aircraft that contributes significantly to carrying only ground and whose integrity is essential in maintaining the overall structural integrity of the aircraft

B. A part of the aircraft that contributes significantly to carrying loads and is essential for maintaining structural integrity

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What is the main function of a Principal Structural Element (PSE)?
A. To reduce the weight of the aircraft
B. To assist in passenger comfort
C. To carry significant loads and maintain structural integrity

C. To carry significant loads and maintain structural integrity

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Which of the following are examples of Principal Structural Elements (PSEs)?
A. Passenger seats, tray tables, and carpeting
B. Engines, tires, and fuel tanks, window wipers, galley equipment, overhead bins
C. Wings, horizontal stabiliser, vertical stabiliser (fin), canard, forward wing, winglets/tip fins, pressurised areas

C. Wings, horizontal stabiliser, vertical stabiliser (fin), canard, forward wing, winglets/tip fins, pressurised areas

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How are aircraft strength requirements specified?
A. In terms of the aircraft’s weight only
B. In terms of the maximum loads expected in service and a maximum load plus a factor of safety
C. In terms of passenger capacity and speed

B. In terms of the maximum loads expected in service and a maximum load plus a factor of safety

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What is the difference between flight limit loads and ultimate limit loads?
A. Flight limit loads are always higher than ultimate limit loads
B. Flight limit loads are the maximum loads expected in service, while ultimate limit loads are flight limit loads multiplied by a factor of safety
C. Flight limit loads apply only to large aircraft, while ultimate limit loads apply to all aircraft

B. Flight limit loads are the maximum loads expected in service, while ultimate limit loads are flight limit loads multiplied by a factor of safety

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Where can the criteria for the design, standards, and structural requirements for large aircraft be found?
A. In the CAA Regulations
B. In CS-25 Certification Specifications
C. In the manufacturer’s design handbook

B. In CS-25 Certification Specifications

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What are flight limit loads?
A. The maximum loads expected in service
B. The loads that are multiplied by a factor of safety
C. The load at which structural damage will occur

A. The maximum loads expected in service

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What are ultimate limit loads?
A. Flight limit loads multiplied by a factor of safety
B. The maximum loads expected in service
C. Loads that occur during takeoff and landing

A. Flight limit loads multiplied by a factor of safety

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What does tension stress resist?
A. The force that compresses and shortens the part
B. The force that pulls and tries to extend the part
C. The force that twists the part

B. The force that pulls and tries to extend the part

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What is the tensile stiffness of a component?
A. Its resistance to compression forces
B. Its resistance to bending forces
C. Its resistance to tensile forces

C. Its resistance to tensile forces

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What does compression stress tend to do to a part?
A. Squeeze and shorten the part
B. Twist the part
C. Stretch and extend the part

A. Squeeze and shorten the part

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What is torsion (twisting) stress caused by?
A. A twisting effect produced by a torque
B. A force applied at the center of the component
C. A combination of tension and compression

A. A twisting effect produced by a torque

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What does shear stress resist?
A. Forces that cause one layer of material to move relative to an adjacent layer
B. Forces that compress and shorten the material
C. Forces that twist the material

A. Forces that cause one layer of material to move relative to an adjacent layer

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What are bending stresses a result of?
A. A combination of tension and compression in the material
B. Pure tension forces
C. Only compression forces

A. A combination of tension and compression in the material

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In most cases, structural members are designed to carry which types of loads?
A. Side loads
B. End loads
C. Rotational loads

B. End loads

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What is the primary requirement for components like cowling and fairing?
A. To carry the stresses imposed by flight or landing loads
B. To maintain a smooth streamlined profile
C. To resist tension and compression forces

B. To maintain a smooth streamlined profile

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What is the determination of the loads to be imposed on an aircraft called?
A. Load distribution
B. Stress analysis
C. Structural testing

B. Stress analysis

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Where can the designated category for each structure be found?
A. In the aircraft’s operational manual
B. In the manufacturer’s manuals
C. In the pilot’s handbook

B. In the manufacturer’s manuals

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What are the three structural categories of aircraft?
A. Primary structure, secondary structure, tertiary structure
B. Primary structure, support structure, safety structure
C. Engine structure, fuselage structure, wing structure

A. Primary structure, secondary structure, tertiary structure

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What are components within the primary structure referred to as?
A. Structural Safety Items (SSIs)
B. Principal Structural Elements (PSEs)
C. Secondary Structural Members

B. Principal Structural Elements (PSEs)

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What is primary structure in an aircraft?
A. Any part of the framework that could lead to catastrophic consequences if it fails during flight or while grounded
B. A secondary structure that supports non-critical components
C. A decorative element that improves the appearance of the aircraft

A. Any part of the framework that could lead to catastrophic consequences if it fails during flight or while grounded

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What are the potential consequences if primary structure fails during flight or while grounded?
A. Decreased fuel consumption
B. Loss of control, catastrophic structural collapse, harm to occupants, failure of the power unit, unintended operation, or incapability to perform a service
C. Increased cabin space and comfort

B. Loss of control, catastrophic structural collapse, harm to occupants, failure of the power unit, unintended operation, or incapability to perform a service

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Why are some primary structure components listed as Structurally Significant Items (SSIs)?
A. Because they are cosmetic and need regular polishing
B. Because they require special inspections due to their importance to structural integrity
C. Because they are frequently replaced during routine maintenance

B. Because they require special inspections due to their importance to structural integrity

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What does secondary structure refer to in an aircraft? A. All decorative and interior components B. Non-primary structural components that still have structural significance and strength C. Components with no load-bearing purpose

B. Non-primary structural components that still have structural significance and strength

How does secondary structure compare to primary structure in terms of failure risk? A. Secondary structure is more likely to cause catastrophic failure B. Secondary structure fails more easily than primary structure C. Secondary structure is less likely to weaken to the point of failure compared to primary structure

C. Secondary structure is less likely to weaken to the point of failure compared to primary structure

Which of the following is an example of secondary structure? A. Engine mount B. Fuselage stringer C. Main landing gear

B. Fuselage stringer

What does tertiary structure refer to in an aircraft? A. The primary load-bearing components of the aircraft B. The remaining lightly stressed components added for various purposes C. The control systems and electronics

B. The remaining lightly stressed components added for various purposes

Which of the following is an example of tertiary structure? A. Wing spar B. Fairing C. Fuselage frame

B. Fairing

Where should a technician look to correctly classify a part of the aircraft's structure? A. The pilot's handbook B. The aircraft's flight manual C. The Aircraft Maintenance Manual (AMM) or Structural Repair Manual (SRM)

C. The Aircraft Maintenance Manual (AMM) or Structural Repair Manual (SRM)

What is the main structural design philosophy of aircraft manufacturers? A. To make aircraft as lightweight as possible B. To produce the highest quality aircraft using the best design, materials, and manufacturing techniques C. To focus only on aesthetics

B. To produce the highest quality aircraft using the best design, materials, and manufacturing techniques

What is a disadvantage of the fail-safe concept? A) It increases the weight of the aircraft B) It makes the aircraft more prone to fatigue C) It reduces the strength of structural members

A) It increases the weight of the aircraft

What is the fail-safe concept in aircraft structure design? A) A system that allows structural failure to lead to collapse B) A method that ensures redundancy in structural members to prevent collapse if one fails C) A method to improve fuel efficiency

B) A method that ensures redundancy in structural members to prevent collapse if one fails

How does the fail-safe method work in aircraft design? A) By ensuring all parts of the structure are designed to fail simultaneously B) By duplicating critical structural members so if one fails, the other can carry the load C) By reducing the number of components in the structure to lower the risk of failure

B) By duplicating critical structural members so if one fails, the other can carry the load

What does the safe-life concept in aircraft design focus on? A) How long a structure can remain in service before reaching fatigue damage B) How to minimize weight and increase speed C) How to reduce the cost of maintenance

A) How long a structure can remain in service before reaching fatigue damage

How is the safe-life of an aircraft structure typically calculated? A) By estimating the number of flight cycles or operating hours before failure B) By considering the weight of the aircraft and the number of passengers C) By calculating the maximum speed the aircraft can safely reach

A) By estimating the number of flight cycles or operating hours before failure

What is the safe-life of an aircraft component typically set to? A) One-third of the maximum calculated cycles or operating hours from testing B) Half of the expected lifetime of the aircraft C) The total number of hours a component can run without maintenance

A) One-third of the maximum calculated cycles or operating hours from testing

What is a key difference between the safe-life concept and the damage tolerance concept? A) Safe-life predicts how long a structure can remain in service before fatigue damage, while damage tolerance focuses on handling failures safely B) Safe-life doesn't require any testing, while damage tolerance relies on repeated load testing C) Safe-life is used only for passenger aircraft, while damage tolerance is used for cargo planes

A) Safe-life predicts how long a structure can remain in service before fatigue damage, while damage tolerance focuses on handling failures safely

What does the safe-life concept fail to account for? A) The specific environment an aircraft operates in, such as corrosion or high-stress conditions B) The weight of the aircraft C) The number of components in the aircraft

A) The specific environment an aircraft operates in, such as corrosion or high-stress conditions

What is the main goal of the damage tolerance concept in aircraft design? A) To design structures that can withstand significant damage without failure B) To reduce the weight of aircraft structures C) To ensure components do not need regular inspections

A) To design structures that can withstand significant damage without failure

What is a key limitation of the damage tolerance concept? A) It relies on human inspection, which can have errors B) It requires no maintenance C) It makes the aircraft too heavy to fly

A) It relies on human inspection, which can have errors

What do reference planes in aircraft design help with? A) Determining the aircraft's flight path B) Identifying the location of components and calculating the center of gravity C) Setting the maximum altitude of the aircraft

B) Identifying the location of components and calculating the center of gravity

How many main structural units does an aircraft have? A) Four B) Five C) Six

B) Five

How many major zones are defined in the zonal identification system for aircraft? A) Six B) Seven C) Eight

C) Eight

What is the major zone number for the lower half of the fuselage in the zonal identification system? A) 100 B) 200 C) 300

A) 100

What does major zone "200" represent in the zonal identification system? A) Upper half of the fuselage B) Landing gear and landing gear doors C) Power plants and the struts

A) Upper half of the fuselage

Which major zone in the zonal identification system covers the empennage, including the aft fuselage and the horizontal and vertical stabilisers? A) 300 B) 400 C) 700

A) 300

Which major zone represents the left wing in the zonal identification system? A) 600 B) 500 C) 700

B) 500

Which major zone is assigned to the right wing in the zonal identification system? A) 500 B) 600 C) 800

B) 600

What does the major zone "700" represent in the zonal identification system? A) Landing gear and landing gear doors B) Doors C) Right wing

A) Landing gear and landing gear doors

Which major zone is assigned to the doors in the zonal identification system? A) 800 B) 200 C) 300

A) 800

What major zone is assigned to the power plants and struts? A) 400 B) 500 C) 600

A) 400

How are sub-major zones identified in the zonal identification system? A) By the first digit of the number code B) By the second digit of the number code C) By the third digit of the number code

B) By the second digit of the number code

How are sub-major zones typically numbered on the right-hand side of the aircraft? A) With odd numbers B) With even numbers C) With numbers based on the aircraft's weight

B) With even numbers

How are sub-major zones numbered on the left-hand side of the aircraft? A) With even numbers B) With odd numbers C) With numbers based on flight hours

B) With odd numbers

What does the third digit of the number code in the zonal identification system represent? A) The sub-major zone B) The exact location of a component within the zone C) The aircraft’s fuel capacity

B) The exact location of a component within the zone

What happens when multiple access panels are located in one zone? A) They are given a different number code B) They are identified with a letter after the zone numbers C) They are ignored in the zonal system

B) They are identified with a letter after the zone numbers

Which of the following are the types of reference planes used in aircraft design? A) Vertical planes, horizontal planes, and longitudinal planes B) Diagonal planes, vertical planes, and center planes C) Horizontal planes, radial planes, and elliptical planes

A) Vertical planes, horizontal planes, and longitudinal planes

Is Zone 900 a valid zone in the aircraft zonal identification system? A) Yes, it represents a specific area of the aircraft B) No, Zone 900 is not a valid zone C) Yes, but only for smaller aircraft

B) No, Zone 900 is not a valid zone

For smaller aircraft, the second digit of the sub-major zone code ranges from: A) 1 to 3 B) 1 to 6 C) 1 to 9

B) 1 to 6

For larger aircraft, the second digit of the sub-major zone code ranges from: A) 1 to 3 B) 1 to 6 C) 1 to 9

C) 1 to 9

In the identification of access panels and service doors, what do the first and second letters represent? A) The panel's weight and size B) The position of the panel or door from forward to aft, inboard to outboard, and bottom to top, and the left or right side C) The material type and function of the panel

B) The position of the panel or door from forward to aft, inboard to outboard, and bottom to top, and the left or right side

What are Body Stations or Fuselage Stations (BS or FS) used for in the station identification system? A) To measure the distance from the nose of the aircraft to a vertical plane at a right angle to the body centerline B) To identify the position of the wings C) To locate the aircraft's tail section

A) To measure the distance from the nose of the aircraft to a vertical plane at a right angle to the body centerline

What is the purpose of Waterlines (WL) in the station identification system? A) To measure the horizontal planes at a right angle to the body stations and buttock lines B) To define the left and right sides of the aircraft C) To mark the weight of the aircraft

A) To measure the horizontal planes at a right angle to the body stations and buttock lines

What does Wing Stations (WS) refer to in the station identification system? A) The vertical planes at the aircraft’s centerline B) The reference planes measured from a butt line reference point or wing rib 1 C) The coordinates of the landing gear

B) The reference planes measured from a butt line reference point or wing rib 1

What are Component Stations (CS) used for in the station identification system? A) To number components such as flying control surfaces, engine nacelles, and pylons B) To measure fuel efficiency C) To assign part numbers to each aircraft component

A) To number components such as flying control surfaces, engine nacelles, and pylons

What does the term Buttock Line (BL) refer to in the station identification system? A) A horizontal plane at a right angle to the body stations B) A vertical plane parallel to the body centerline plane C) A coordinate system used for wing stations

B) A vertical plane parallel to the body centerline plane

How is the body station (or fuselage station) measured in the station identification system? A) By the distance from the aircraft's tail section B) By the distance from a point in front of the nose of the aircraft C) By the distance from the aircraft’s wings

B) By the distance from a point in front of the nose of the aircraft

Where are waterlines typically measured from in the station identification system? A) From a parallel imaginary plane below the aircraft fuselage and sometimes below the landing gear B) From the aircraft’s horizontal stabiliser C) From the aircraft's wingtip

A) From a parallel imaginary plane below the aircraft fuselage and sometimes below the landing gear

Where are wing stations typically measured from in the station identification system? A) From the aircraft’s vertical stabilizer B) From a butt line reference point or from wing rib 1 C) From the aircraft’s fuselage centerline

B) From a butt line reference point or from wing rib 1

What type of stress does shear refer to? A) Stress that resists twisting forces B) Stress that resists sliding between material layers C) Stress that resists a crushing force

B) Stress that resists sliding between material layers

What is the main purpose of riveted joints in aircraft construction? A) To resist tension forces B) To resist shear forces C) To resist torsion forces

B) To resist shear forces

What is bending stress a combination of? A) Compression and shear B) Tension and shear C) Compression and tension

C) Compression and tension

What is hoop stress in the context of aircraft cabins? A) The circumferential tensile stress acting on the skin panels B) The longitudinal stress acting on the pressure bulkheads C) The stress due to bending forces on the fuselage

A) The circumferential tensile stress acting on the skin panels

What does strain refer to? A) The stress caused by cyclic loads B) The ratio of deformation caused by stress C) The tensile strength of a material

B) The ratio of deformation caused by stress

What causes fatigue damage in aircraft materials? A) Constant stress without deformation B) Cyclic or alternating loads C) Heat exposure

B) Cyclic or alternating loads

For any given pressure, how does the hoop stress compare to the longitudinal stress in an aircraft cabin structure? A) The hoop stress is half the value of the longitudinal stress B) The hoop stress is equal to the longitudinal stress C) The hoop stress will be twice the value of the longitudinal stress

C) The hoop stress will be twice the value of the longitudinal stress

Why is effective drainage and ventilation important in aircraft structures? A) To prevent trapped fluids from causing corrosion and damage B) To increase the weight of the aircraft C) To improve the aerodynamic efficiency of the aircraft

A) To prevent trapped fluids from causing corrosion and damage

How are fluids directed to the drain holes in the aircraft fuselage? A) By a system of longitudinal and cross-drain paths through the stringers and the frame B) By a series of pumps and valves placed along the fuselage C) By gravity only, with no additional drainage paths

A) By a system of longitudinal and cross-drain paths through the stringers and the frame

What happens to the bilge-like valves when the aircraft becomes pressurised? A) The valves stay open to allow air to escape B) The valves close to seal off the interior of the fuselage C) The valves open further to allow more condensation to drain

B) The valves close to seal off the interior of the fuselage

Where are drain holes typically located on the aircraft? A) On the wings B) On the aircraft's lower fuselage C) Near the cockpit

B) On the aircraft's lower fuselage

Why are bilge-like valves spring-loaded to an open position when the aircraft is depressurised? A) To release excess fuel B) To allow condensation to drain from the fuselage C) To allow air to circulate through the fuselage

B) To allow condensation to drain from the fuselage

What is the primary purpose of ventilation in aircraft cavities that may contain flammable vapour or water? A) To reduce the temperature inside the aircraft B) To allow the vapour to evaporate and prevent accumulation C) To circulate air to improve comfort for passengers

B) To allow the vapour to evaporate and prevent accumulation

What type of ventilation system is used in areas such as engine nacelles to ensure airflow? A) Air conditioning systems B) Ram air inlets and exit points C) Exhaust fans

B) Ram air inlets and exit points

Why is it essential that all openings designed for ventilation in the aircraft are unobstructed? A) To prevent excess moisture inside the aircraft B) To ensure that vapour can safely escape and prevent hazardous accumulation C) To improve fuel efficiency

B) To ensure that vapour can safely escape and prevent hazardous accumulation

Why are cockpit indicators installed with ease of removal in mind? A) To ensure they can be easily upgraded B) To facilitate easy removal for maintenance or replacement C) To improve the aircraft's overall aesthetic

B) To facilitate easy removal for maintenance or replacement

What is the primary function of the external metal structure in protecting an aircraft from lightning strikes? A) To provide additional weight to the aircraft B) To shield internal areas from lightning strikes and protect electrical systems from electromagnetic interference C) To enhance the appearance of the aircraft

B) To shield internal areas from lightning strikes and protect electrical systems from electromagnetic interference

What are the two main types of damage caused by lightning strikes on an aircraft? A) Mechanical and electrical damage B) Direct and indirect damage C) Physical and electrical damage

B) Direct and indirect damage

What external areas of the aircraft should be inspected for damage after a lightning strike? A) Only the fuselage nose section B) External surfaces, static dischargers, fuel system valves, and other critical components C) Only the wings and stabilisers

B) External surfaces, static dischargers, fuel system valves, and other critical components

Where are the most common areas for lightning strikes to occur on an aircraft? A) Cockpit windows B) Fuselage nose section and the trailing edges of wings and stabilisers C) Wings only

B) Fuselage nose section and the trailing edges of wings and stabilisers

What is considered direct damage from a lightning strike on an aircraft? A) Burned, melted, or distorted surfaces at strike points B) Failure of radio communication C) Temporary flickering of cabin lights

A) Burned, melted, or distorted surfaces at strike points

What is indirect damage caused by a lightning strike? A) Damage to wing flaps B) Damage to electrical systems due to electrical transients on wiring C) Surface corrosion from rain exposure

B) Damage to electrical systems due to electrical transients on wiring

What is the function of bonding metallic components to the airframe? A) To improve fuel efficiency B) To allow safe dissipation of electrical currents like lightning strikes C) To strengthen rivets and joints

B) To allow safe dissipation of electrical currents like lightning strikes

What does a static discharger do on an aircraft? A) Increases electrical charge to avoid interference B) Discharges built-up static electricity safely into the atmosphere C) Redirects engine exhaust away from the fuselage

B) Discharges built-up static electricity safely into the atmosphere

Why is bonding necessary on an aircraft? A) To add weight for better balance B) To ensure components maintain the same electrical potential and prevent static build-up C) To protect components from overheating

B) To ensure components maintain the same electrical potential and prevent static build-up

Which of the following is a benefit of aircraft bonding and grounding? A) Increases fuel efficiency B) Minimises fire hazards by preventing sparks between metallic components C) Enhances passenger comfort through better cabin pressure

B) Minimises fire hazards by preventing sparks between metallic components

Which of the following are reasons for using bonding on an aircraft? A) To improve fuel consumption B) To minimise radio interference, prevent sparks, and protect against lightning C) To increase engine power

B) To minimise radio interference, prevent sparks, and protect against lightning

What is the maximum number of terminals allowed on one grounding stud? A) Two B) Four C) Six

B) Four

What is the correct definition of grounding in aircraft systems? A) Connecting an aircraft to a charging station B) Electrically connecting conductive objects to the aircraft structure or a return path to safely complete a circuit C) Disconnecting all power from the aircraft before maintenance

B) Electrically connecting conductive objects to the aircraft structure or a return path to safely complete a circuit

What is required for grounding installations in fuel-vapour areas of an aircraft? A) A single ground connection is sufficient B) Dual grounds must be installed in fuel-vapour areas C) No grounding is necessary in fuel-vapour areas

B) Dual grounds must be installed in fuel-vapour areas

When installing grounds on an aircraft, which of the following is required? A) AC, DC, and shields must be kept together B) AC, DC, and shield grounds must be separated C) Only a single ground should be used in fuel-vapour areas

B) AC, DC, and shield grounds must be separated

What is used as a conductor for current returns for the single-wire electrical systems? A) The aircraft’s metallic structure B) Electrical wires C) Grounding points

A) The aircraft’s metallic structure

Why are composite materials unsuitable for bonding, earth returns, and lightning strike dissipation? A) They have high electrical resistance B) They are too heavy C) They conduct electricity easily

A) They have high electrical resistance

How is a ground plate integrated into the composite airframe? A) By using copper wiring B) By bonding an aluminium wire mesh into the composite structure during manufacture C) By adding a conductive coating to the composite surface

B) By bonding an aluminium wire mesh into the composite structure during manufacture

What is direct bonding in composite materials? A) Mounting equipment directly onto the composite material B) Exposing the mesh and installing a bonding wire and connector C) Exposing the mesh and mounting the equipment directly onto the conductive path

C) Exposing the mesh and mounting the equipment directly onto the conductive path

What is indirect bonding in composite materials? A) Installing a bonding wire and connector after exposing the mesh B) Directly bonding the equipment to the mesh C) Applying a conductive coating to the structure

A) Installing a bonding wire and connector after exposing the mesh

What must be removed from the surfaces to ensure a low-resistance connection for bonding leads? A) Non-conducting paint and anodising films B) Dust and dirt C) Lubricants

A) Non-conducting paint and anodising films

What is the maximum resistance that should be obtained for bonding connections? A) 0.025 Ω B) 0.1 Ω C) 1 Ω

A) 0.025 Ω

11.2 A. Airframe Structures - General Concepts Flashcards

(108 cards)