WorksheetsSHEETMETAL & NON-SHEETMETALIC STRUCTURE PRACTICAL EXAM
Total questions: 130
Worksheet time: 1hrs 5mins
(1) When performing a ring (coin tap) test on composite structure, a change in sound may be due to damage or to transition to a different internal structure.
(2) The extent of separation damage in composite structures is most accurately measured by a ring (coin tap) test. Regarding the above statements,
Both No.1 and No.2 are true
Only No.1 is true
Only No.2 is true
Clad aluminum alloys are used in aircraft because they
Can be heat treated much easier than the other forms of aluminum
Are less subject to corrosion than uncoated aluminum alloys
Are stronger than unclad aluminum alloys
A well-designed rivet joint will subject the rivets to
Compressive loads
Shear loads
Tension loads
If a streamline cover plate is to be hand formed using a form block, a piece of dead soft aluminum should first be placed over the hollow portion of the mold and securely fastened in place. The bumping operation should be
Distributed evenly over the face of the aluminum at all times rather than being started at the edges or center
Started by tapping the aluminum lightly around the edges and gradually working down into the center
Started by tapping the aluminum in the center until it touches the bottom of the mold and then working out in all directions
If it is necessary to compute a bend allowance problem and bend allowance tables are not available, the neutral axis of the bend can be
Represented by the actual length of the required material for the bend
Found by adding approximately one-half of the thickness to the bend radius
Found by subtracting the stock thickness from the bend radius
The sight line on a sheet metal flat layout to be bent in a cornice or box brake is measured and marked
One-half radius from either bend tangent line
One radius from either bend tangent line
One radius from the bend tangent line that is placed under the brake
On a sheet metal fitting layout with a single bend, allow for stretching by
Adding the setback to each leg
Subtracting the setback from one leg
Subtracting the setback from both legs
When necessary, what type of cutting fluid is usually acceptable for machining composite laminates?
Water soluble oil
Water displacing oil
Water only
What is indicated by a black ‘smoky’ residue streaming back from some of the rivets on an aircraft?
The rivets were excessively work hardened during installation
Exfoliation corrosion is occurring inside the structure
Fretting corrosion is occurring between the rivets and the skin
What type of bit should be used to drill holes in Plexiglas?
A standard twist drill
A specially modified twist drill
A dulled twist drill
What precaution, if any, should be taken to prevent corrosion inside a repaired metal honeycomb structure?
Prime the repair with a corrosion inhibitor and seal from the atmosphere
Paint the outside area with several coats of exterior paint
None. Honeycomb is usually made from a man-made or fibrous material which is not susceptible to corrosion
Mild steel rivets are used for riveting
A nickel-steel parts
Magnesium parts
Steel parts
A main difference between Lockbolt/Huckbolt tension and shear fasteners (other than their application) is in the
Number of locking collar grooves
Shape of the head
Method of installation
What is the minimum spacing for a single row of aircraft rivets?
Two times the diameter of the rivet shank
Three times the length of the rivet shank
Three times the diameter of the rivet shank
The coefficient of expansion of most plastic enclosure materials is
Greater than both steel and aluminum
Greater than steel but less than aluminum
Less than either steel or aluminum
What should be the included angle of a twist drill for soft metals?
118°
90°
65°
Which part of the 2017-T36 aluminum alloy designation indicates the primary alloying agent used in its manufacture?
2
17
20
Rivet gauge, or transverse pitch is the distance between the
Centers of rivets in adjacent rows
Centers of adjacent rivets in the same row
Heads of rivets in the same row
Which statement is true regarding a cantilever wing?
It has nonadjustable lift struts
No external bracing is needed
It requires only one lift strut on each side
Fiberglass damage that extends completely through a laminated sandwich structure
May be repaired
Must be filled with resin to eliminate dangerous stress concentrations
May be filled with putty which is compatible with resin
Threaded rivets (Rivnuts) are commonly used to
Join two or more pieces of sheet metal where shear strength is desired
Attach parts or components with screws to sheet metal
Join two or more pieces of sheet metal where bearing strength is desired
What should be the included angle of a twist drill for hard metal?
118°
100°
90°
When repairing a small hole on a metal stressed skin, the major consideration in the design of the patch should be
The shear strength of the riveted joint
To use rivet spacing similar to a seam in the skin
That the bond between the patch and the skin is sufficient to prevent dissimilar metal corrosion
A factor which determines the minimum space between rivets is the
Length of the rivets being used
Diameter of the rivets being used
Thickness of the material being riveted
What is the material layer used within the vacuum bag pressure system to absorb excess resin during curing called?
Bleeder
Breather
Release
If a new safety belt is to be installed in an aircraft, the belt must conform to the strength requirements in which documents?
STC 1282
14 CFR Part 39
TSO C22
What is one of the determining factors which permit machine countersinking when flush riveting?
Thickness of the material and rivet diameter are the same
Thickness of the material is less than the thickness of the rivet head
Thickness of the material is greater than the thickness of the rivet head
When balsa wood is used to replace a damaged honeycomb core, the plug should be cut so that
The grain is parallel to the skin
It is about 1/8 inch undersize to allow sufficient bonding material to be applied
The grain is perpendicular to the skin
Under certain conditions, type A rivets are not used because of their
Low strength characteristics
High alloy content
Tendency toward embrittlement when subjected to vibration
Which rivet may be used as received without further treatment?
2024-T4
2117-T3
2017-T3
Cabin upholstery materials installed in current standard category airplanes must
Be fireproof
Be at least flame resistant
Meet the requirements prescribed in Part 43
A rivet set used to drive MS20470 rivets should
Have the same radius as the rivet head
Have a slightly greater radius than the rivet head
Be nearly flat on the end, with a slight radius on the edge to prevent damage to the sheet being riveted
The general rule for finding the proper rivet diameter is
Three times the thickness of the materials to be joined
Two times the rivet length
Three times the thickness of the thickest sheet
MS20426AD-6-5 indicates a countersunk rivet which has
A shank length of 5/16 inch (excluding head)
A shank length 5/32 inch (excluding head)
An overall length of 5/16 inch
Superficial scars, scratches, surface abrasion, or rain erosion on fiberglass laminates can generally be repaired by applying
A piece of resin-impregnated glass fabric facing
One or more coats of suitable resin (room-temperature catalyzed) to the surface
A sheet of polyethylene over the abraded surface and one or more coats of resin cured with infrared heat lamps
Fiberglass laminate damage that extends completely through one facing and into the core
Cannot be repaired
Requires the replacement of the damaged core and facing
Can be repaired by using a typical metal facing patch
When straightening members made of 2024-T4, you should
Straighten cold and reinforce
Straighten cold and anneal to remove stress
Apply heat to the inside of the bend
The classification for high tensile strength fiberglass used in aircraft structure is
E-glass
S-glass
G-glass
Repairs or splices involving stringers on the lower surface of stressed skin metal wings are usually
Not permitted
Permitted only if the damage does not exceed 6 inches in any direction
Permitted but are normally more critical in reference to strength in tension than similar repairs to the upper surface
Which is correct concerning the use of a file?
Apply pressure on the forward stroke, only, except when filing very soft metals such as lead or aluminum
A smoother finish can be obtained by using a double-cut file than by using a single-cut file
The terms 'double-cut' and 'second-cut' have the same meaning in reference to files
The Dzus turnlock fastener consists of a stud, grommet, and receptacle. The stud diameter is measured in
Tenths of an inch
Hundredths of an inch
Sixteenths of an inch
Heat-treated rivets in the D and DD series that are not driven within the prescribed time after heat treatment or removal from refrigeration
Must be reheat treated before use
Must be discarded
May be returned to refrigeration and used later without reheat treatment
Parts fabricated from Alclad 2024-T3 aluminum sheet stock must have all
Bends made with a small radius to develop maximum strength
Bends 90° to the grain
Scratches, kinks, tool marks, nicks, etc., must be held to a minimum
Metal fasteners used with carbon/graphite composite structures
May be constructed of any of the metals commonly used in aircraft fasteners
Must be constructed of material such as titanium or corrosion resistant steel
Must be constructed of high strength aluminum-lithium alloy
The part of a replacement honeycomb core that must line up with the adjacent original is the
Cell side
Ribbon direction
Cell edge
Longitudinal (fore and aft) structural members of a semi-monocoque fuselage are called
Spars and ribs
Longerons and stringers
Spars and stringers
When drilling stainless steel, the drill used should have an included angle of
90° and turn at a low speed
118° and turn at a high speed
140° and turn at a low speed
What is the minimum edge distance for aircraft rivets?
Two times the diameter of the rivet shank
Two times the diameter of the rivet head
Three times the diameter of the rivet shank
The identifying marks on the heads of aluminum alloy rivets indicate the
Degree of dimensional and process control observed during manufacture
Head shape, shank size, material used, and specifications adhered to during manufacture
Specific alloy used in the manufacture of the rivets
A piece of sheet metal is bent to a certain radius. The curvature of the bend is referred to as the
Bend allowance
Neutral line
Bend radius
The installation of Cherrymax and Olympic-lok rivets is accomplished by utilizing
Rivet gun, special rivet set, and bucking bar
A pulling tool
Ordinary hand tools
Which is an identifying characteristic of acrylic plastics?
Zinc chloride will have no effect
Acrylic has a yellowish tint when viewed from the edge
Acetone will soften plastic, but will change its color
The sharpest bend that can be placed in a piece of metal without critically weakening the part is called the
Bend allowance
Minimum radius of bend
Maximum radius of bend
What is the most common method of cementing transparent plastics?
Heat method
Soak method
Bevel method
Which rivet is used for riveting nickel-steel alloys?
2024-aluminum
Mild steel
Monel
If an aircraft’s transparent plastic enclosures exhibit fine cracks which may extend in a network over or under the surface or through the plastic, the plastic is said to be
Hazing
Brinelling
Crazing
Which of the following drill bit types work best when drilling an aramid fiber (Kevlar) composite laminate?
Tool steel with standard grind
Diamond dust coated
Carbide W-point
The purpose of a joggle is to
Allow clearance for a sheet or an extrusion
Increase obstruction for a sheet or an extrusion
Decrease the weight of the part and still retain the necessary strength
What is the purpose of refrigerating 2017 and 2024 aluminum alloy rivets after heat treatment?
To accelerate age hardening
To relieve internal stresses
To retard age hardening
Which fiber to resin (percent) ratio for advanced composite wet lay-ups is generally considered the best for strength?
40:60
50:50
60:40
Sandwich panels made of metal honeycomb construction are used on modern aircraft because this type of construction
Has a high strength to weight ratio
May be repaired by gluing replacement skin to the inner core material with thermoplastic resin
Is lighter than single sheet skin of the same strength and is more corrosion resistant
Which statement is true regarding the inspection of a stressed skin metal wing assembly known to have been critically loaded?
If rivets show no visible distortion, further investigation is unnecessary
If bearing failure has occurred, the rivet shanks will be joggled
If genuine rivet tipping has occurred, groups of consecutive rivet heads will be tipped in the same direction
The Dzus turnlock fastener consists of a stud, grommet, and receptacle. The stud length is measured in
Hundredths of an inch
Tenths of an inch
Sixteenth of an inch
A piece of flat stock that is to be bent to a closed angle of 15° must be bent through an angle of
165°
105°
90°
What is the purpose of a gusset or gusset plate used in the construction and repair of aircraft structures?
To hold structural members in position temporarily until the permanent attachment has been completed
To provide access for inspection of structural attachments
To join and reinforce intersecting structural members
A sheet metal repair is to be made using two pieces of 0.0625-inch aluminum riveted together. All rivet holes are drilled for 1/8-inch rivets. The length of the rivets to be used will be
5/32 inch
3/16 inch
5/16 inch
When making repairs to fiberglass, cleaning of the area to be repaired is essential for a good bond. The final cleaning should be made using
MEK (methyl ethyl ketone)
Soap, water, and a scrub brush
A thixotropic agent
What type loads cause the most rivet failures?
Shear
Bearing
Head
Aircraft structural units, such as spars, engine supports, etc., which have been built up from sheet metal, are normally
Repairable, using approved methods
Repairable, except when subjected to compressive loads
Not repairable, but must be replaced when damaged or deteriorated
Hole filling fasteners (for example, MS20470 rivets) should not be used in composite structures primarily because of the
Possibility of causing delamination
Increased possibility of fretting corrosion in the fastener
Difficulty in forming a proper shop head
When comparing the machining techniques for stainless steel sheet material to those for aluminum alloy sheet, it is normally considered good practice to drill the stainless steel at a
Higher speed with less pressure applied to the drill
Lower speed with more pressure applied to the drill
Lower speed with less pressure applied to the drill
How does acoustic emission testing detect defects in composite materials?
By picking up the ‘noise’ of any deterioration that may be present
By analyzing ultrasonic signals transmitted into the parts being inspected
By creating sonic pictures of the areas being inspected
One of the best ways to assure that a properly prepared batch of matrix resin has been achieved is to
Perform a chemical composition analysis
Have mixed enough for a test sample
Test the viscosity of the resin immediately after mixing
If no scratches are visible after transparent plastic enclosure materials have been cleaned, their surfaces should be
Polished with rubbing compound applied with a damp cloth
Buffed with a clean, soft, dry cloth
Covered with a thin coat of wax
The length of time that a catalyzed resin will remain in a workable state is called the
Pot life
Shelf life
Service life
Which is considered good practice concerning the installation of acrylic plastics?
When nuts and bolts are used, the plastic should be installed hot and tightened to a firm fit before the plastic cools
When rivets are used, adequate spacer or other satisfactory means to prevent excessive tightening of the frame to the plastic should be provided
When rivets or nuts and bolts are used, slotted holes are not recommended
The primary alloying agent of 2024-T3 is indicated by the number
2
20
24
How many of the following are benefits of using microballoons when making repairs to laminated honeycomb panels?
1. Greater concentrations of resin in edges and corners
2. Improved strength to weight ratio
3. Less density
4. Lower stress concentrations
2,3, and 4
1,2, and 4
All of the above
Alloy 2117 rivets are heat treated
By the manufacturer and do not require heat treatment before being driven
By the manufacturer but require reheat treatment before being driven
To a temperature of 910 to 930°F and quenched in cold water
One of the main advantages of Hi-Lok type fasteners over earlier generations is that
They can be removed and reused again
The squeezed can be installed with ordinary hand tools
They can be installed with ordinary hand tools
The most important factors needed to make a flat pattern layout are
Radius, thickness, and mold line
Radius, thickness, and degree of bend
The length of the legs (flat sections)
A potted compound repair on honeycomb can usually be made on damages less than
4 inches in diameter
2 inches in diameter
1 inch in diameter
Shallow scratches in sheet metal may be repaired by
Burnishing
Buffling
Stop drilling
The monocoque fuselage relies largely on the strength of
Longerons and formers
Skin or covering
Bulkheads and longerons
You can distinguish between aluminum and aluminum alloy by
Filing the metal
Testing with an acetic solution
Testing with a 10 percent solution of caustic soda
When bending metal, the material on the outside of the curve stretches while the material on the inside of the curve compresses. That part of the material which is not affected by either stress is the
Mold line
Bend tangent line
Neutral line
How many MS20470 AD-4-6 rivets will be required to attach a 10 x 5 inch plate, using a single row of rivets, minimum edge distance and 4D spacing?
56
54
52
When installing transparent plastic enclosures which are retained by bolts extending through the plastic material and self-locking nuts, the nuts should be
Tightened to a firm fit, plus one full turn
Tightened to a firm fit, then backed off one full turn
Tightened to a firm fit
When repairing puncture-type damage of a metal faced laminated honeycomb panel, the edges of the doubler should be tapered to
Two times the thickness of the metal
100 times the thickness of the metal
Whatever is desired for a neat, clean appearance
Fiberglass laminate damage not exceeding the first layer or ply can be repaired by
Filling with a putty consisting of a compatible resin and clean, short glass fibers
Sanding the damaged area until aerodynamic smoothness is obtained
Trimming the rough edges and sealing with paint
Most rivets used in aircraft construction have
Dimples
Smooth heads without markings
Identification marks on their heads
Composite fabric material is considered to be the strongest in what direction?
Fill
Warp
Bias
The markings on the head of a Dzus fastener identify the
Body diameter, type of head, and length of the fastener
Body type, head diameter, and type of material
Manufacturer and type of material
The strength and stiffness of a properly constructed composite buildup depends primarily on
A 60 percent matrix to 40 percent fiber ratio
The orientation of the plies to the load direction
The ability of the fibers to transfer stress to the matrix
When riveting dissimilar metals together, what precautions must be taken to prevent an electrolytic action?
Treat the surfaces to be riveted together with a process called anodic treatment
Place a protective separator between areas of potential electrical difference
Avoid the use of dissimilar metals by redesigning the unit according to the recommendations outlined in AC 43.13-1A
A DD rivet is heat treated before use to
Harden and increase strength
Relieve internal stresses
Soften to facilitate riveting
When a piece of aluminum alloy is to be bent using minimum radius for the type and thickness of material
The piece should be bent slowly to eliminate cracking
The layout should be made so that the bend will be 90° to the grain of the sheet
Less pressure than usual should be applied with the movable (upper) clamping bar
Which of the following are generally characteristic of carbon/graphite fiber composites? 1. Flexibility 2. Stiffness 3. High compressive strength 4. Corrosive effect in contact with aluminum 5. Ability to conduct electricity
1 and 3
2,3 and 4
1,3 and 5
The classification for fiberglass reinforcement material that has high resistivity and is the most common is
E-glass
S-glass
G-glass
When repairing large, flat surfaces with polyester resins, warping of the surface is likely to occur. One method of reducing the amount of warpage is to
Add an extra amount of catalyst to the resin
Use short strips of fiberglass in the bonded repair
Use less catalyst than normal so the repair will be more flexible
Joggles in removed rivet shanks would indicate partial
Bearing failure
Torsion failure
Shear failure
The dimensions of an MS20430AD-4-8 rivet are
1/8 inch in diameter and 1/4 inch long
1/8 inch in diameter and 1/2 inch long
4/16 inch in diameter and 8/32 inch long
When inspecting a composite panel using the ring test/tapping method, a dull thud may indicate
Less than full strength curing of the matrix
Separation of the laminates
An area of too much matrix between fiber layers
Which of the following, when added to wet resins, provide strength for the repair of damaged fastener holes in composite panels?
1. Microballoons
2. Flox
3. Chopped fibers
2 and 3
1 and 3
1,2, and 3
Which procedure is correct when using a reamer to finish a drilled hole to the correct size?
Turn the reamer in the cutting direction when enlarging the hole and in the opposite direction to remove from the hole
Turn the reamer only in the cutting direction
Apply considerable pressure on the reamer when starting the cut and reduce the pressure when finishing the cut
Which part(s) of a semi-monocoque fuselage prevents tension and compression from bending the fuselage?
The fuselage covering
Longerons and stringers
Bulkhead and skin
What is generally the best procedure to use when removing a solid shank rivet?
Drill through the manufactured head and shank with a shank size drill and remove the rivet with a punch
Drill to the base of the manufactured rivet head with a drill one size smaller than the rivet shank and remove the rivet with a punch
Drill through the manufactured head and shank with a drill one size smaller than the rivet and remove the rivet with a punch
What is the minimum edge distance allowed for aluminum alloy single lap sheet splices containing a single row of rivets as compared to a joint with multiple rows, all rivets being equal diameter?
The minimum edge distance for the single row is greater than that for the multiple row
The minimum edge distance for the single row is less than that for the multiple row
The minimum edge distance for the single row is equal to that for the multiple row
When an MS20470D rivet is installed, its full shear strength is obtained
Only after a period of age hardening
By the cold working of the rivet metal in forming a shop head
By heat treating just prior to being driven
A single-lap sheet splice is to be used to repair a section of damaged aluminum skin. If a double row of 1/8-inch rivets is used, the minimum allowable overlap will be
1/2 inch
3/4 inch
13/16 inch
The length of rivet to be chosen when making a structural repair that involves the joining of 0.032-inch sheet, drilled with a No. 30 drill, is
7/16 inch
5/16 inch
1/4 inch
A sheet metal repair is to be made using two pieces of 0.040-inch aluminum riveted together. All rivet holes are drilled for 3/32-inch rivets. The length of the rivets to be used will be
1/8 inch
1/4 inch
5/16 inch
Unless otherwise specified, the radius of a bend is the
Inside radius of the metal being formed
Inside radius plus one-half the thickness of the metal being formed
Which of the following need not be considered when determining minimum rivet spacing?
Rivet diameter
Rivet length
Type of material being riveted
The preferred way to make permanent repairs on composites is by
Bonding on metal or cured composite patches
Riveting on metal or cured composite patches
Laminating on new repair plies
Which of these methods may be used to inspect fiberglass/honeycomb structures for entrapped water?
1. Acoustic emission monitoring
2. X-ray
3. Backlighting
1 and 2
1 and 3
2 and 3
Which rivets should be selected to join two sheets of .032-inch aluminum?
MS20425D-4-3
MS20470AD-4-4
MS20455DD-5-3
Select the alternative which best describes the function of the flute section of a twist drill
Provides a method for cooling oil to be delivered to the cutting surface
Forms the area where the drill bit attaches to the drill motor
Forms the cutting edges of the drill point
Which of the following are generally characteristic of aramid fiber (Kevlar) composites?
1. High tensile strength
2. Flexibility
3. Stiffness
4. Corrosive effect in contact with aluminum
5. Ability to conduct electricity
1 and 2
2,3 and 4
1,3 and 5
One method of inspecting a laminated fiberglass structure that has been subjected to damage is to
Strip the damaged area of all paint and shine a strong light through the structure
Use dye-penetrant inspection procedures, exposing the entire damaged area to the penetrant solution
Use an eddy current probe on both sides of the damaged area
The length of a rivet to be used to join a sheet of .032-inch and .064-inch aluminum alloy should be equal to
Two times the rivet diameter plus .064 inch
One and one-half times the rivet diameter plus .096 inch
Three times the rivet diameter plus .096 inch
Rivet pitch is the distance between the
Centers of rivets in adjacent rows
Centers of adjacent rivets in the same row
Heads of rivets in the same row
A category of plastic material that is capable of softening or flowing when reheated is described as a
Thermoplastic
Thermocure
Thermoset
Which rivet is used for riveting magnesium alloy structures?
Mild steel
5056 aluminum
Monel
Proper pre-preg composite lay-up curing is generally accomplished by
1. Applying external heat
2. Room temperature exposure
3. Adding a catalyst or curing agent to the resin
4. Applying pressure
2 and 3
1 and 4
1, 2, and 4
Applying pressure
The flat layout or blank length of a piece of metal from which a simple L-shaped bracket 3 inches by 1 inch is to be bent depends upon the radius of the desired bend. The bracket which will require the greatest amount of material is one which has a bend radius of
1/8 inch
1/2 inch
1/4 inch
What reference tool is used to determine how the fiber is to be oriented for a particular ply of fabric?
Fill clock (or compass)
Bias clock (or compass)
Warp clock (or compass)
Repairing advanced composites using materials and techniques traditionally used for fiberglass repairs is likely to result in
Restored strength and flexibility
Improved wear resistance to the structure
An unairworthy repair
The aluminum alloys used in aircraft construction are usually hardened by which method?
Cold-working
Aging
Heat Treatment
The shop head of a rivet should be
One and one-half times the diameter of the rivet shank
One-half times the diameter of the rivet shank
One and one-half times the diameter of the manufactured head of the rivet
