AME-S STRUCTURES #2

What are Servo Tabs?. Servo tabs are operated by hydraulic actuators moved by the control yoke and rudder pedals. In the event of a hydraulic system failure, in a process known as Manual Reversion the flight controls column moves the servo tabs and aerodynamic forces caused by the deflected tab move the main control surface. Servo tabs function mainly as damping units that absorb vibration from the wings and tail surfaces, helping stabilize the aircraft structure by automatically adjusting to turbulence without affecting the main controls. Servo tabs are secondary trim devices that lock the control surfaces in place during cruise flight, preventing unwanted movement and reducing drag, and they operate independently from the pilot’s control system. Servo tabs are small aerodynamic panels installed to distribute cooling air across the trailing edges of control surfaces, ensuring temperature balance and preventing overheating of the flight control mechanisms.

What are Wing Fence?. Simple method to stop or reduce the Span wise airflow. Devices installed to redirect the chordwise airflow. Panels used mainly to reduce trailing-edge turbulence. Structures designed to limit the downward wash over the wing.

What is ‘’coning’’ in a helicopter?. In a semi rigid and rigid rotor system, the rotor takes a conical shape as the blades bend upwards when two forces are applied upon take off. In an articulated rotor system, the blades assume an upward angle trough movement about the flapping hinge. In a semi rigid system, the rotor disc flattens during lift as the blades deflect downward under load and rotate evenly around the hub. In an articulated rotor system, the blades assume a downward angle as centrifugal force reduces during takeoff, creating a cylindrical rotation pattern around the mast. In a rigid rotor system, the rotor remains completely flat in flight and develops no upward bending, allowing the blades to rotate horizontally without forming any conical shape.

What causes Vertical Vibration on a helicopter?. Generally caused by some disparity in lift, points to an out-of-track condition. Usually produced by unequal blade drag, indicating a need for pitch-angle adjustment on one rotor. Commonly created by minor differences in blade loading, typically tracing back to an incorrect trim balance. Often the result of variations in rotor thrust, suggesting improper synchronization between the rotor blades.

What causes Lateral Vibration on a helicopter?. Most often caused by an out-of-balance condition of the rotor. Typically produced by uneven blade pitch changes during rotation. Commonly generated by excessive drag variations between the rotor blades. Usually created by minor differences in blade tracking at cruise speed.

When applied to aluminum alloy sheet, the term alclad indicated that the surfaces have been treated for corrosion by?. 5% of the material on both side is coated with pure aluminum. 5% of the material on both sides is coated with alclad alloy. 10% of the material on both side is coated with pure aluminum. 5% of the material on both sides is coated with anodized layer.

When drilling materials, a general rule is the Harder the material, the ____ the speed and the ___ the feed. Lower, Greater. Faster, Slower. Higher, Lower. Quicker, Softer.

Which aluminium rivet requires to be heat treated before installation?. 2017 D. 1100 A. 5056 H. 2024 T.

Which aluminium rivet requires to be kept frozen until they are ready to be driven?. 2024 DD. 2036 D. 2117 AD. 2014 E.

Can you replace a Solid rivet with a Friction-lock rivet?. Not size for size, the friction-lock must be one size up (1/32 larger). Yes, friction-lock rivets are always installed the same size as the original solid rivet. Yes, a friction-lock rivet must always be one size smaller than the removed solid rivet. No, friction-lock rivets can not replace solid rivets without any change in diameter.

Can you replace a Solid rivet with a Mechanical Lock rivet?. Yes. No.

Can you replace a solid rivet for a hucklock?. Yes, but quite expensive tooling required for installation. No, because the installation method is completely different and the joint would not meet the required strength specifications. Only if the structure is redesigned, since the fastener dimensions and installation loads are not directly compatible. Yes, although doing so usually results in improper fit and reduced reliability due to the difference in fastening principles.

Can you replace a solid rivet for a Cherrylock?. Yes, uses a lock ring. Shear and Bearing strengths. No, requires a special sleeve and provides limited load capacity. No, only installed with hydraulic equipment and not suitable for replacements. Yes, but needs a threaded insert and does not meet shear requirements.

Can you replace a solid rivet for a Cherrymax?. Yes, Economical to use. No, it is not recommended for structural applications. Yes, but it provides lower shear strength than solid rivets. No, cherrymax rivets cannot be installed with standard tooling.

What temperature range can a Cherrymax withstand?. 250°F to 1400°F. 180°F to 900°F. 300°F to 1100°F. 200°F to 750°F.

What is the single shear-strength of an AD 2117 1/8 Rivet?. 331 Pounds. 274 Pounds. 389 Pounds. 415 Pounds.

What is the overall tolerance for an Interference Fit?. 0.000 to 0.003 smaller than the fastener. 0.002 to 0.005 larger than the fastene. 0.001 to 0.004 equal to the fastener. 0.003 to 0.006 wider than the fastener.

What are two critical factors to obtain maximum strength from a riveted repair?. Pitch and Edge distance. Material to use. Thickness. Grip Lenght and Diameter.

What is Transversal Pitch?. The distance between rows of rivets in a multiple-row layout. The distance between rivets measured along a single row. The spacing from the edge of the sheet to each rivet. The measurement used to determine the diameter of the rivet hole.

When multiple rows of rivets are used in a layout, the transverse pitch should be about. 75% of the pitch and the rivets should be staggered. 60% of the pitch and the rivets should be aligned. 60% of the pitch and the rivets should be staggered. 50% of the pitch and the rivets should be offset slightly.

What are the two ways of Dimpling sheet metal?. Coin and Radius Dimpling. Press and Form dimpling. Heat and Pressure dimpling. Die and Hand dimpling.

What is Coin Dimpling?. Process of dimpling using a hydraulic press. Process of forming dimples by lightly tapping the sheet with a hand mallet. Process of shaping dimples by applying uniform heat to soften the metal. Process of creating dimples using a rolling tool to press the material inward.

What is Radius Dimpling?. Process of dimpling, can be used in smaller area because its equipment is small. Process of forming slight recesses, typically applied when the material thickness limits deeper shaping. Process of shaping light depressions, usually chosen when access to large machinery is restricted. Process of creating shallow contours, commonly used in areas where clearance for tools is reduced.

What is hot dimpling?. A form of coin dimpling but the dies are heated to prevent the material cracking, used with Magnesium and some of the harder aluminum alloys such as 7075. A method of dimpling that uses cold-formed dies to soften the material before shaping, typically applied to thin aluminum skins. A process of metal preparation in which the dies are chilled to reduce distortion and improve the accuracy of the dimple. A technique of forming dimples by gradually pressing the sheets in stages to avoid overstressing the alloy during shaping.

‘’K’ Value?. Tangent x (Bend degree/2). Tangent x (Bend radius/4). Tangent x (Angle of bend ÷ 3). Tangent x (Material thickness/2).

How do you cut Kevlar?. Ceramic scissors. Diamond shears. Rotary cutters. Carbon blades.

How do you reduce damage to composite when drilling?. Back with a wood block or use a drill stop. Use a slow drill speed to avoid splintering the laminate. Apply downward pressure without supporting the backside. Drill freehand without clamping the composite panel.

How do you deal with fraying when drilling trough Kevlar?. Apply a quick curing epoxy to the fuzzed area. Use a low-speed drill bit to prevent the fibers from lifting. Coat the drilled zone with a thin layer of resin after the hole is completed. Apply masking tape over the surface before drilling the material.

How do you avoid fraying when drilling trough Kevlar?. Use a Drill bit with a brad point and a c-shaped cutting edge. Use a standard twist drill without support, allowing the fibers to separate naturally. Apply light heat to the drilling area so the kevlar softens and cuts more cleanly. Drill at a very high rpm with no backing material to minimize tool pressure on the fibers.

How do you drill in Fiberglass or Carbon/Graphite?. Use Carbide or Diamond-coated tools. Use high-speed steel bits for all drilling operations. Use standard twist drills without any special coating. Use soft-metal drill bits to prevent surface scratching.

What is Peel Ply?. Perforated parting film, helps ‘’feathers’’ the seams or overlaps to produce a smooth finish. Light protective fabric layer, used mainly to increase surface gloss during composite finishing. Thin backing sheet, applied to prevent resin flow and harden the laminate during curing. Temporary filler layer, designed to add rigidity and reduce panel deformation during layup.

What is a Bleeder?. Placed over a repair to absorb excess resin. Used to keep trapped air inside the laminate. Designed to prevent heat from reaching the laminate. Placed under the repair to block vacuum pressure.

Are pre-cured patches considered permanent repairs?. No, they do not offer same strength as the original structure, they are Temporary. Yes, they are used mainly for quick field applications, they cannot match the durability of a bonded repair, they are considered only provisional. Yes, they provide limited reinforcement to the damaged structure, they are not designed for full load restoration, they are mostly temporary solutions. Yes, they are generally applied without full surface preparation, they lack complete structural bonding, they are acceptable only for short-term use.

Are Resin Injection repairs considered Permanent repairs?. Not in the case of structural parts For non-structural parts yes. Yes in the case of structural parts And also for non-structural parts. Considered permanent on all composite assemblies regardless of location. Generally accepted as permanent on primary structures without limitations.

How do you distinguish between acrylic and acetate?. Two methods: Acetone and Burning Acrylic – Soften no color change/Dark Smoke Acetate – Does not Soften, turns white/Clear Flame. Two methods: Heat and Scratching Acrylic – Softens quickly/Light fumes Acetate – Remains rigid/Produces yellow smoke. Two methods: Solvent wipe and Weight test Acrylic – Becomes flexible/No visible residue Acetate – Stays brittle/Leaves a powder trace. Two methods: UV light and Impact test Acrylic – Shows slight glow/Cracks cleanly Acetate – No glow/Breaks with rough edges.

How do you increase the strength of an acrylic cemented join?. Heat treatment of a joint will disperse the solvent through a greater volume of the plastic and will increase the strength of the joint. Cooling the joint rapidly will trap the solvent near the surface and will reduce the bonding depth of the plastic. Applying extra solvent to the joint will saturate the material and will create a softer bond that weakens under load. Using high-pressure clamping will force excess solvent out of the joint and will prevent the plastic surfaces from fusing properly.

What important precautions are to be taken when polishing Acrylic?. -Do not alter the optical properties and distort the pilot’s vision -Do not reduce the thickness to the point where the window would be weakened. -Avoid using excessive pressure which may overheat the surface -Never allow abrasive residue to remain trapped on the acrylic window. -Ensure the polishing pad remains dry at all times -Remove material quickly to improve visibility through the acrylic. -Apply strong chemical cleaners to speed up the polishing process -Use coarse abrasives to eliminate minor scratches more efficiently.

What are the two most prominent methods of welding aircraft structures?. Fusion Welding / Non-Fusion Welding. Thermal bonding / Pressure welding. Arc joining / Resistance brazing. Metal fusing / Alloy bonding.

What is Fusion Welding?. The blending of compatible metals into one common part or joint. The process of joining metals by applying pressure without melting the base material. A technique that bonds dissimilar materials using adhesives instead of heat. A method in which metals are joined by mechanical fastening rather than thermal fusion.

What is Non-Fusion Welding?. Joining of metals by adhesion of a metal to another (Brazing and Soldering). Using pressure only to join parts without melting the base metals. Forming a joint by mechanically fastening two metals together. Joining metals by bonding them with a nonmetallic adhesive layer.

What are the three principal methods of fusion welding?. Gas, Electrical Arc, Electrical Resistance. Laser, Plasma arc, Electron beam. Thermite, Induction, Carbon arc. Friction, Ultrasonic, Forge welding.

What are important considerations to obtain the proper amount of penetration and proper weld dimensions?. Use the proper type and size of filler rod and appropriate welding technique for the thickness and type of material to be joined. Select a filler rod based on convenience and apply any welding method regardless of the material thickness. Choose a random filler rod size and rely on a single technique for all metals without considering their properties. Use oversized filler rods and focus mainly on speed rather than adapting the welding technique to the material.

What is the single most important characteristic of a good weld?. Proper penetration (Depth of Fusion). Insufficient surface cleaning before welding, causing weak fusion and irregular bead formation. Using excessive filler rod that produces overheating and leads to poor weld geometry. Applying an improper torch angle which reduces penetration and alters the weld dimensions.

What is the determining factor in selecting the tungsten electrodes for TIG welding?. Size and type of metal to be welded. Based on the thickness of the filler rod required. Chosen according to the welding current being used. Determined by the shielding gas type selected.

Penetration and Bead height are measured relative to the Thickness (T) of the________. Base metal. Filler metal. Parent alloy. Weld surface.

What are 4 ways to reduce Warping and Residual Stress when welding?. -Distributing heat more evenly -Reducing the amount of heat applied -Using jigs to hold the metal in place -Allowing for space between the edges of the joint. -Using excessive heat during welding -Applying pressure unevenly along the joint -Reducing cooling time to speed up the process -Clamping the metal tightly to restrict any natural movement. -Preheating the entire assembly to a very high temperature -Increasing the weld bead size on all passes -Forcing the metals together to minimize spacing -Applying rapid quenching immediately after welding. -Overlapping weld passes to concentrate heat in one area -Eliminating gaps to ensure full metal contact -Applying continuous welding without breaks -Using thicker filler rod to increase deposited material.

Brazing temperature?. 800F. 600F. 650F. 400F.

Most aircraft gas welding is done on thin-gauge steel that ranges from __ to __ Gauge. 16 to 20 Gauge. 13 to 16 Gauge. 10 to 20 Gauge. 20 to 20 Gauge.

What are the 3 Electrical Arc Welding techniques?. TIG / SMAW / MIG. FCAW / SAW / PAW. GTAW / CAW / TIG. RW / LBW / EBW.

What does SMAW stands for?. Shielded Metal Arc Welding. hielded Manual Arc Welding. Surface Metal Arc Welding. Structural Manual Arc Work.

What does MIG stands for?. Metal Inert Gas. Melted Ionized Gas. Mixed Injection Gradient. Modified Internal Generator.

How do you join two dissimilar metals?. Brazing. Welding. Soldering. Friction bonding.

How do you join metals without distorting the part or destroying the heat treatment?. Brazing. Fusion welding. Resistance soldering. Thermal bonding.

What is KERF?. The cut made by an oxyacetylene cutting torch. The gap produced by a plasma cutter when severing metal. The groove left by a bandsaw blade while cutting stock. The material removed by a waterjet stream during a cut.

What Electric Arc welding method is the most used in aircraft maintenance?. Tungsten Inert Gas (TIG). Shielded Metal Arc Welding (SMAW). Gas Metal Arc Welding (GMAW). Plasma Arc Welding (PAW).

Which factor determines the size of the torch tip and filler rod used?. Thickness of the material. Type of welding machine. Color of the base metal. Material of base metal.

What temperature can TIG welding achieve?. Up to 1100°F. Up to 850°F. Up to 950°F. Up to 1250°F.

How do you select the Tungsten Electrodes for TIG welding?. Size and Type of metal to be welded. Color and Shape of the electrode tip used. Length and Weight of the tungsten being selected. Voltage and Amperage of the welding machine.

What are the 3 types of electrodes used in TIG welding?. Pure Tungsten Zirconium Tungsten Thorium Tungsten. Pure tungsten Zirconium tungsten Cerium tungsten. Hafnium tungste Lanthanum tungsten Yttrium tungsten. Pure tungsten Hafnium tungsten Titanium tungsten.

Can you use Butt Joints to join Aircraft structural tubing?. No, they are too weak. Yes, they are strong enough.

What is important when Welding Magnesium?. Extremely active metal, oxidation increases as temperature is raised, produce oxygen as a by-product of combustion and is not extinguishable by normal means. Highly reactive alloy, melting point rises under heat, forms stable oxides during welding and requires special shielding to prevent defects. Very sensitive material, surface impurities increase with temperature, generates intense sparks when heated and needs controlled atmosphere protection. Easily contaminated metal, reaction rate changes as heat is applied, creates brittle oxide layers during welding and demands careful cleaning beforehand.

How do you repair a Dent on a longeron or cross member? (Straight Tubing). By Welding a sleeve over the damage, using Butt/lap/rosette Welds. By forming a shaped insert over the damaged area and bonding it with approved adhesive. By removing the dented section and installing a reinforced splice assembly. By attaching an external doubler plate and securing it with structural fasteners.

How do you do a Tube splicing with an Inner sleeve reinforcement?. Cut damaged tube at 30°, cut the inner sleeve five times as long as the tube diameter If the inner sleeve is too tight, cool the inner sleeve and heat the outer sleeve Hold the inner sleeve using Rosette welds. -Cut the damaged tube at 45°, clean the inner sleeve lightly before insertion, secure the joint using only two rosette welds -Trim the tube at 20°, slide an inner sleeve only twice the tube diameter, finish the splice with a single perimeter weld around the tube -Remove the damaged section squarely, insert an inner sleeve matching the tube length, fasten the splice by applying spot welds at each end. -Remove the damaged tube using a straight 90° cut for better fit -Use an inner sleeve equal to the exact length of the damaged section -Fasten the sleeve with spot welds instead of rosette welds. -Cut the tube at a 45° angle to reduce stress concentration -Install an inner sleeve only two diameters long for easier alignment -Secure the sleeve with a single rosette weld on each side.

What should you account for when designing a welded repair?. Allowance for expansion and contraction due to heat. Consideration for alignment shifts caused by residual stress during cooling. Allowance for slight dimensional changes produced by localized weld distortion. Compensation for minor structural movement resulting from thermal gradients.

On a Gas Welding Oxyacetylene setup, which is the big bottle, and which is the small?. Big: Oxygen Cylinder Small: Acetylene. Big: Acetylene Cylinder Small: Oxygen. Big: Nitrogen Cylinder Small: Hydrogen. Big: Fuel Gas Cylinder Small: Compressed Air.

How do you regulate the flow of oxygen in Oxyacetylene welding?. Two-stage Regulator. Single-stage Valve. Needle Flow Meter. Pressure Relief Gauge.

Which way should you practice initial welds?. Forehand Direction. Backhand Direction. Vertical Direction. Circular Motion.

What does an oxyacetylene cutting torch consists of?. A normal welding torch with an additional orifice for High pressure oxygen and a valve. A standard welding torch with an extra acetylene nozzle and pressure gauge. A normal welding torch with a single oxygen valve only. A dual-fuel torch with adjustable flame length and built-in regulator.

In Fabric Covering what does CAB means?. Cellulose Acetate Butyrate. Calcium Acetate Binder. Cellulose Acrylic Blend. Carbonated Acetate Base.

The Wrap of threads in a section of fabric runs the _____ of the fabric. Length. Width. Diagonal. Crosswise.

The Wrap direction is designated as ____ °. 0°. 90°. 45°. 180°.

The Wet/Fill directions is ____°. 90° runs perpendicular to the Wrap. 0° runs parallel to the Wrap. 45° runs diagonal to the Wrap. 180° runs opposite to the Wrap.

What is the Selvage Edge?. The edge parallel to the Wrap. The edge perpendicular to the Wrap. The edge running diagonal to the Wrap. The edge at the center of the Fabric.

What is the Bias?. The fiber orientation that runs 45° to the wrap threads. The fiber orientation that runs parallel to the wrap threads. The fiber orientation that runs perpendicular to the wrap threads. The fiber orientation that runs 90° to the fill threads.

Cotton intermediate grade is?. A lighter cotton fabric. A heavier cotton fabric. A synthetic cotton blend. A coarse cotton fabric.

Glider fabric is?. A verry fine-weave. A coarse-weave. A medium-weave. A loosely-woven.

What has become one of the most popular covering material?. Synthetic polyester. Cotton fabric. Linen material. Fiberglass cloth.

Surface tape come in two configurations: Bias cut / Straight-cut. Diagonal-cut / Cross-cut. Parallel-cut / Perpendicular-cut. Circular-cut / Zigzag-cut.

Surface tape comes in widths ranging from ___ to___ inches. 3/4 to 6 inches. 1/2 to 4 inches. 1 to 8 inches. 2 to 10 inches.

Surface tape shrinks in width by as much as ____ its original width. 1/3. 1/2. 1/4. 2/3.

How frequently is fabric covering’s strength evaluated on an airplane?. During each 100 hour, annual or other required airworthiness inspection. Only during the first flight after covering. Every 500 flight hours regardless of inspection. Only when visible damage is observed.

Can Nitrate dope be applied over a Butyrate film?. No. Yes.

How do you repair a L-Shaped tear in fabric?. -Brush butyrate dope to soften the finish, scrape with a dull knife -Tack the corner of the L, then Sew the tear -Apply dope and patching tapes. -Cut out the L-shaped section entirely and replace with new fabric only -Heat the fabric until it melts, then press the edges together -Glue the edges with epoxy and leave unreinforced. -Stitch the tear directly without softening or tacking -Apply only tape without dope or sewing -Fill the tear with cotton batting and coat with varnish.

When spraying clear dope over pigmented dope, use less than about ___ % clear dope. Less than 20%. Less than 40%. Less than 10%. Less than 50%.

What happens if you spray Nitrate dope over Butyrate Dope?. Causes the dope film of the topcoat to peel off, coming off in strips. Causes the dope to harden immediately without adhesion. Produces a smooth, glossy finish without issues. Makes the underlying fabric shrink excessively.

What are Pinholes?. Small bubbles forming on the finish surface, caused when the solvent break through the surface of the dope which has prematurely hardened. Small bubbles forming on the finish surface, caused when the solvent evaporates too quickly before the dope sets. Tiny air pockets appearing on the surface, created when the dope film is applied over a damp or oily substrate. Minute voids forming on the finish layer, caused when the dope reacts with contaminants on the fabric before curing.

What are Fisheyes?. Localized spots that do not dry, caused by Wax, Oil or Silicone. Localized areas that remain glossy, caused by improper thinning or contamination with dust. Small circular defects in the finish, caused by trapped air or moisture under the dope. Tiny raised spots that resist drying, caused by residues of grease or cleaning solvents.

For seaplane or agricultural aircraft, what should be applied over the wash primer?. An Epoxy primer. A Zinc chromate primer. A Polyester-based topcoat. An Alkyd enamel primer.

What is the ‘’induction time’’. Time allowed for the base and activator to begin to polymerize and link together. Time required for the mixture to fully cure and harden completely. Time it takes for the solvent to evaporate from the surface of the coating. Time allowed for the components to settle before applying the next coat.

How is the viscosity of paint measured?. Viscosity cup, the amount of time in seconds between the time the cup is lifted and the first break in the stream flowing out of the hole in the bottom. Flow meter, the amount of time in seconds it takes for paint to coat a standard panel evenly. Dip test, measuring the thickness of the paint left on a rod after immersion and withdrawal. Flow cone, the time in seconds it takes for paint to drain completely from a conical cup.

What is the pot life (time between mixing and time it is unusable) for polyurethanes?. 6 to 8 hours. 1 to 2 hours. 1 to 3 hours. 5 to 10 hours.