Fabrics Flashcards
- What is the main reason Sitka spruce is used in aircraft structures?• a) Low cost
• b) Strength and shock resistance
• c) High-density material
• d) Easy to glue
- b) Strength and shock resistance
- Which of the following is not a requirement for Sitka spruce to meet aircraft grade specifications?• a) Kiln-dried under approved conditions
• b) Minimum specific gravity of 0.36
• c) Maximum slope of grain of 1:10
• d) No fewer than six annular rings per inch
c) Maximum slope of grain of 1:10
What does solid wood refer to in aircraft construction?
• a) An assembled product of wood and glue • b) Beams or spars made from a single piece of wood • c) Layers glued together with grain running parallel • d) High-density commercial products like compreg
. b) Beams or spars made from a single piece of wood
- Which wood type can be used as a substitute for Sitka spruce despite difficulties with gluing?• a) Noble Fir
• b) Douglas Fir
• c) Yellow Poplar
• d) Port Orford White Cedar
d) Port Orford White Cedar
What is the maximum permissible slope of grain for wood used in aircraft structures?
• a) 1:10 • b) 1:15 • c) 1:20 • d) 1:25
B) 1:15
Which wood type has slightly less strength than Sitka spruce and low shock resistance?
• a) Douglas Fir • b) Noble Fir • c) Yellow Poplar • d) Western Hemlock
C) yellow poplar
Why is aviation wood usually quarter-sawn?
• a) To reduce warping • b) To increase strength • c) To reduce shrinkage • d) To improve workability
c) To reduce shrinkage
How is the number of growth rings per inch determined for wood assessment?
• a) Measuring the width of each ring • b) Counting rings on the wide face of the board • c) Counting rings at the end of the board • d) Measuring the distance between the rings
c) Counting rings at the end of the board
Which of the following is NOT a factor that contributes to the rate of fabric deterioration on an aircraft?
a) Type of operation
b) Exposure to wind
c) Climate and humidity
d) Storage conditions
Answer: b) Exposure to wind
How often should the fabric covering of an aircraft be checked?
a) Once every 15 years
b) Monthly
c) As per the approved maintenance schedule and before Airworthiness Certificate renewal
d) Only when defects are noticed
Answer: c) As per the approved maintenance schedule and before Airworthiness Certificate renewal
What happens to an aircraft structure if it is stored outside?
a) It becomes stronger due to sun exposure
b) Ultraviolet radiation and sun exposure can damage the structure
c) The fabric becomes waterproof
d) The structure cools down more rapidly
Answer: b) Ultraviolet radiation and sun exposure can damage the structure
Which of the following is NOT a defect that should be inspected in the fabric covering?
a) Loose finishing tape
b) Fabric tears
c) Excessively taut fabric
d) Stone damage
Answer: c) Excessively taut fabric
What are the consequences of excessive fabric tension?
a) Improved aerodynamics
b) Warping of longerons, wing ribs, and trailing edges
c) Reduced drag
d) Decreased fuel efficiency
Answer: b) Warping of longerons, wing ribs, and trailing edges
What causes temporary wrinkles in a fabric coated with dope?
a) High-quality dope film
b) Rapid cooling in the shade
c) Moisture absorption, thick dope coating, and rapid temperature changes
d) Application of varnish
Answer: c) Moisture absorption, thick dope coating, and rapid temperature changes
Which fabric is unaffected by UV radiation but deteriorates with acid rain and chafing?
a) Natural fibers
b) Polyester filaments
c) Glass fabric
d) Synthetic fibers
Answer: c) Glass fabric
How should cracks in the dope coating be repaired?
a) Leave them as they are
b) Seal them or remove and replace coatings in the affected area
c) Apply water
d) Heat the area
Answer: b) Seal them or remove and replace coatings in the affected area
Why is protecting the structure beneath the fabric covering important?
a) To add extra weight
b) To prevent wood rot and allow inspections
c) To make the aircraft look newer
d) To increase speed
Answer: b) To prevent wood rot and allow inspections
Why should wooden aircraft structures be kept in well-ventilated hangars?
a) To allow air to circulate around the engine
b) To prevent moisture condensation that leads to wood deterioration
c) To protect from bird droppings
d) To allow easier access for maintenance
b) To prevent moisture condensation that leads to wood deterioration
What is the purpose of wiping wooden aircraft structures with a damp cloth and applying furniture polish?
a) To disinfect the wood
b) To remove paint residue
c) To keep the wood clean and polished
d) To prepare the wood for repair
c) To keep the wood clean and polished
Which of the following is NOT a required property of wood preservatives for aircraft structures?
a) They must be non-toxic to fungi, pests, and marine organisms
b) They must possess satisfactory permanence
c) They must be free from objectionable properties
d) They should not have corrosive properties
a) They must be non-toxic to fungi, pests, and marine organisms
What is the main purpose of applying chemical preservatives to wooden aircraft structures?
a) To change the color of the wood
b) To protect the wood from fungi, insects, and marine borers
c) To make the wood heavier for stability
d) To prevent cracking from temperature changes
b) To protect the wood from fungi, insects, and marine borers
What is the primary objective of interior finishes on wooden aircraft structures?
a) To make the interior look aesthetically pleasing
b) To protect the wood against moisture content changes
c) To prevent cracking from sunlight exposure
d) To ensure the wood does not conduct electricity
b) To protect the wood against moisture content changes
Why should end grain surfaces of wooden aircraft members be sealed thoroughly?
a) They are less absorbent and can be left unsealed
b) They are more absorbent and vulnerable to moisture entry
c) They can crack easily when exposed to sunlight
d) They are already protected by the wood’s natural oils
b) They are more absorbent and vulnerable to moisture entry
How should bolt holes in wooden aircraft structures be sealed?
a) With oil to prevent drying
b) With varnish or acceptable sealer and allowed to cure before installation
c) With glue to hold the bolts in place
d) With paint to match the aircraft’s color
b) With varnish or acceptable sealer and allowed to cure before installation
How do dark-colored finishes affect wooden aircraft surfaces compared to lighter colors?
a) They reflect more sunlight, keeping the wood cooler
b) They cause higher temperatures and weaken the wood
c) They make the aircraft more visible in the sky
d) They prevent moisture from entering the wood
b) They cause higher temperatures and weaken the wood
What is the maximum allowable slope of the grain for aviation-grade timber?
a) 1:10
b) 1:12
c) 1:15
d) 1:20
c) 1:15
Why are knots considered a defect in wood used for aircraft construction?
a) They add weight to the wood
b) They can cause the wood to split under pressure
c) They reduce the aesthetic value of the wood
d) They weaken the wood
d) They weaken the wood
What is the significance of pitch pockets in wood?
a) They are beneficial for adding flexibility
b) They are filled with resin and only acceptable in the center of a beam
c) They enhance the color and texture of the wood
d) They prevent the wood from warping
b) They are filled with resin and only acceptable in the center of a beam
Why is compression wood not suitable for aircraft construction?
a) It is too flexible
b) It is denser and weaker due to compressive stresses
c) It absorbs too much moisture
d) It has an irregular color
b) It is denser and weaker due to compressive stresses
Why must adhesives used in aircraft construction meet specific performance criteria?
a) To prevent aesthetic damage
b) To ensure compatibility with plastic parts
c) To comply with the Aircraft Maintenance Manual
d) To provide flexibility in repairs
c) To comply with the Aircraft Maintenance Manual
What causes compression failures in wood?
a) High temperatures during drying
b) A tree falling and landing unevenly
c) Exposure to strong winds
d) Growth in damp conditions
b) A tree falling and landing unevenly
How can decay in wood be identified?
a) By its uniform color
b) By its tendency to splinter easily
c) By streaks in the grain and wood breaking off in chunks when probed
d) By its hardness
c) By streaks in the grain and wood breaking off in chunks when probed
Which of the following describes a “check” in wood?
a) A lengthwise separation of wood fibers
b) A crack running across the annual rings during seasoning
c) A separation between two annual rings
d) A dark stain caused by decay
b) A crack running across the annual rings during seasoning
What is dry rot and what causes it?
a) A type of cracking due to high temperatures
b) A form of decay caused by fungi, requiring minimal moisture
c) A dark discoloration from exposure to sunlight
d) A warping of wood due to uneven growth
b) A form of decay caused by fungi, requiring minimal moisture
What is the reason casein glue is considered obsolete for aircraft repairs?
a) It is too expensive
b) It deteriorates over time and prevents other glues from curing properly
c) It does not stick well to metal
d) It is only available in small quantities
b) It deteriorates over time and prevents other glues from curing properly
Which glue is known for its high water resistance and is commonly used in aircraft repairs?
a) Casein glue
b) Plastic resin glue
c) Resorcinol glue
d) Epoxy adhesives
c) Resorcinol glue
What are the three important steps for a successful wood joint in aircraft repair?
a) Proper cleaning, sanding, and polishing
b) Using epoxy, applying pressure, and heating
c) Preparing the wood surface, using quality glue, and following the correct bonding technique
d) Checking moisture levels, painting, and drilling holes
c) Preparing the wood surface, using quality glue, and following the correct bonding technique
Why should sanding not be used to smooth the wood surface before bonding?
a) It dulls the color of the wood
b) It changes the flatness and rounds the corners of the wood
c) It makes the glue dry too quickly
d) It causes moisture absorption
b) It changes the flatness and rounds the corners of the wood
What is the recommended clamping pressure for hardwood when using resorcinol glue?
a) 862 kPa (125 psi) – 1034 kPa (150 psi)
b) 1034 kPa (150 psi) – 1379 kPa (200 psi)
c) 500 kPa (72 psi) – 800 kPa (116 psi)
d) 1200 kPa (174 psi) – 1500 kPa (218 psi)
b) 1034 kPa (150 psi) – 1379 kPa (200 psi)
How should the strength of a glued joint be tested?
a) By tapping with a hammer
b) By applying heat
c) By placing it in a vice and prising the joint apart
d) By checking its color
c) By placing it in a vice and prising the joint apart
What is an advantage of epoxy adhesives in aircraft repairs?
a) They require high pressure to work
b) They provide better color to the wood
c) They have excellent working properties and require less attention to joint quality
d) They are easily removed with water
c) They have excellent working properties and require less attention to joint quality
Why must a repaired wooden aircraft structure be as strong as the original structure?
a) To save costs on materials
b) To ensure aircraft balance
c) To maintain structural integrity and safety standards
d) To reduce weight
Answer: c) To maintain structural integrity and safety standards
What materials should ideally be used for repairing a wooden aircraft structure?
a) Any materials available
b) The same materials as the original structure
c) Lighter materials for weight reduction
d) Metal for better strength
Answer: b) The same materials as the original structure
Which of the following is not a common type of wooden spar used in aircraft construction?
a) Box beam spar
b) U-beam spar
c) C-section spar
d) Plain rectangular spar
Answer: b) U-beam spar
What should be done if a longitudinal crack is found in a solid wood spar?
a) Fill the crack with glue
b) Apply reinforcing plates on both sides
c) Replace the entire spar
d) Ignore if the crack is small
Answer: b) Apply reinforcing plates on both sides
What is the correct angle for a scarf repair in wooden structures?
a) 1:2
b) 1:5
c) 1:10 or 1:12
d) 1:20
Answer: c) 1:10 or 1:12
In which area is a splice repair not permitted on a solid wood spar?
a) Under attachment fittings for the wing root
b) Along the spar’s midsection
c) At the wing tips
d) Near the fuselage
Answer: a) Under attachment fittings for the wing root
How should a broken cap strip be repaired between upright members?
a) By replacing the entire rib
b) Cutting it to 12 times its thickness and reinforcing it with a block
c) Using nails to fix the crack
d) Applying glue only
Answer: b) Cutting it to 12 times its thickness and reinforcing it with a block
What is the primary reason for trailing edge moisture damage?
a) Exposure to rain
b) Clogged drainage grommets
c) Poor quality wood
d) Excessive flying
Answer: b) Clogged drainage grommets
What is the difference between a scarf patch and a splayed patch repair?
a) Scarf patch is for small holes, and splayed patch is for large holes
b) Scarf patch is beveled at a 12:1 slope, while splayed patch is at a 5:1 slope
c) Scarf patch uses nails, and splayed patch uses screws
d) Both have the same bevel slope
Answer: b) Scarf patch is beveled at a 12:1 slope, while splayed patch is at a 5:1 slope
Which material was historically significant in the construction of early aircraft like the Wright Flyer?
A) Aluminum
B) Cotton and Linen
C) Polyester
D) Glass-fibre
B
Which method is used when the back of the skin is accessible for a scarf patch repair?
a) Apply glue and cover with a fabric patch
b) Install a backing block temporarily and support with gussets
c) Only use clamps
d) Hammer nails into the surface
Answer: b) Install a backing block temporarily and support with gussets
What is the primary direction in fabric construction that must be aligned parallel to the flight direction?
A) Weft
B) Bias
C) Selvage Edge
D) Warp
D
What is the main drawback of using nitrate dope in aircraft fabric coatings?
A) Poor adhesion
B) High flammability
C) Low durability
D) Poor moisture protection
B
Which fabric characteristic allows manipulation of the fabric to form contoured shapes?
A) Warp
B) Bias
C) Weft
D) Selvage Edge
B
Why is a combination of nitrate dope and butyrate dope used on aircraft fabrics?
A) For better color retention
B) To provide adhesion and reduce flammability
C) To increase the fabric’s weight
D) To reduce the cost of coating
B
Which fabric type deteriorates mainly due to UV exposure, requiring protective coatings?
A) Cotton
B) Glass-fibre
C) Polyester-fibre
D) Linen
C
What are aluminium solids added to butyrate dope intended to protect against?
A) Moisture
B) UV radiation
C) Flammability
D) Dirt
B
Which term describes the tightly woven edge of fabric that prevents threads from unraveling?
A) Warp
B) Bias
C) Weft
D) Selvage Edge
D
What safety precaution is NOT necessary when applying aircraft dope?
A) Wearing PPE
B) Using in a well-ventilated environment
C) Ignoring the manufacturer’s safety data sheets
D) Avoiding direct skin contact
C
What is the recommended storage condition for aircraft fabrics?
A) In humid and warm conditions
B) At 20°C in a dry, clean environment away from sunlight
C) In a cold, damp environment
D) At freezing temperatures
B
Which factors influence the rate of deterioration of fabric coverings on an aircraft?
A) Climate, operation type, storage conditions, maintenance
B) Fabric color and design
C) Airspeed and altitude
D) Engine power and fuel type
A
What must be checked periodically to maintain the airworthiness certificate of a light aircraft?
A) The engine components
B) The landing gear
C) The fabric coverings
D) The fuel system
C
Which of the following is NOT a defect requiring repair in aircraft fabric coverings?
A) Mould and fungi
B) Loose finishing tape
C) Smooth coatings
D) Broken or missing rib stringing
C
What are the three types of inspection panels used in fabric-covered aircraft?
A) Wood Frames, Hinged Panels, Magnetic Panels
B) Zip Panels, Bolt-on Panels, Screw Panels
C) Wood Frames, Zip Panels, Spring Panels
D) Spring Panels, Velcro Panels, Button Panels
C
How do Wood Frames function as inspection panels?
A) By using zippers to allow access
B) By using magnets to secure openings
C) By doping a celluloid frame onto fabric and cutting inside the frame
D) By sliding open like a window
C
Which type of inspection panel is suitable for locations requiring frequent inspection?
A) Wood Frames
B) Zip Panels
C) Spring Panels
D) Magnetic Panels
B
Why are mechanical punch testers not approved testing devices?
A) They are too expensive
B) They are too small to handle
C) Their accuracy depends on multiple factors, such as calibration and brittleness
D) They provide instant and accurate results
C
What does the Maule Punch Tester measure?
A) Air pressure inside the aircraft
B) Fabric color fading
C) Fabric breaking strength in psi
D) Fabric weight
C
What should be done if the Maule Punch Tester punctures the fabric?
A) Replace the aircraft
B) Conduct more accurate field tests
C) Fly the aircraft as usual
D) Paint over the puncture
B
What is a disadvantage of using the Seyboth Punch Tester?
A) It does not measure fabric strength accurately
B) It requires repair of the fabric after testing
C) It is too large to carry
D) It gives readings in metric units only
B
Which type of fabric are the Seyboth and Maule Punch Testers designed for?
A) Polyester
B) Nylon
C) Cotton and Linen
D) Synthetic blends
C
