Aircraft Maintenance Practices PDF - AAE4109 - Jan 2025

AAE4109 Aircraft Maintenance Practices (HKAR-66 M6(B1) Part D and M7(B1) Part B) M7.3 Tools  2 Jan 2025 M 7.3 Tools >Common hand tool types; Common power tool types; Operation and use of precision measuring tools; Lubrication equi...

AAE4109 Aircraft Maintenance Practices (HKAR-66 M6(B1) Part D and M7(B1) Part B) M7.3 Tools  2 Jan 2025 M 7.3 Tools >Common hand tool types; Common power tool types; Operation and use of precision measuring tools; Lubrication equipment and methods; Operation, function and use of electrical general test equipment. 3 Jan 2025 Introduction > Servicing of an aircraft, requires the dismantling, cleaning, examination, adjustment and re-assembly of the parts in accordance with the maintenance schedule. > Further aspects of the work may require the manufacture of simple components from metal or other materials, the drilling and tapping of holes, removal of burrs and other operations. > A reasonable degree of skill, in the use of hand tools is, therefore, to be expected from all trades-persons. This skill can only be obtained by practice, but it may be stated, that the more efficient the tool, then the better will be the finished work. 4 Jan 2025 Common Hand Tools > General Purpose Tools Hammers and Mallets Screwdrivers Pliers Needle-nose Pliers, Slip-joint (Gas) Pliers, Locking Pliers, Internal Ring Pliers, External Ring Pliers Wrenches Allen Wrench, Box Wrench, Open-End Wrench, Adjustable (Crescent) Wrench, Socket Wrenches, Crowfoot-type Wrench, Strap Wrench, Torque Wrench Punches Centre Punch, Prick Punch, Pin Punch, Drift Punch, Transfer Punch > Metal Cutting Tools Hand Files, Hand Hacksaw, Scraper, Chisels, Hand Snips, Drills, Hole Cutters, Reamers, Countersink, Taps Jan 2025 and Die. 5 General Purpose Tools > Hammers and Mallets Classified by their weight and type of head The use of the wrong hammer can cause damage to the material and personal injury. Metal-head hammers are usually sized according to the weight of the head without the handle. 4 oz. for the light work, lb. 8 oz. hammer is the common size. 6 Jan 2025  > The main types of engineering hammers are: Ball Peen: The flat surface is used for most general-purpose work whilst the ball peen is used primarily for riveting-type operations. Straight Peen: Used for general work, the narrow, straight peen being particularly A. Ball-peen hammer B. Straight-peen hammer suitable for use where access to the work is C. Cross-peen hammer limited. Cross Peen: As for the straight peen, but the axis of the peen is at 90° to that of the shaft. Hide Copper Face: The rawhide gives a firm resilient blow that will not mark the finished Ball-peen hammer Straight-peen hammer work, while the copper face give high impact blow and may be used for heavier types of work than the hide face. Hide copper face hammer 7 Jan 2025  Rubber Head and Plastic Face: A category of soft-faced hammer designed to offer driving force without damaging work surfaces. They may have one of each type of face on each end of Plastic face mallet the head. Claw Hammer: Primarily used in Rubber mallet carpentry. The face is used for driving nails into whilst the claw is used for pulling them from wood. Body Hammer: Not commonly used in Craw hammer aircraft work, as they are primarily used to remove dents and blemishes from sheet metal. They are also known as planishing hammers. Planishing hammer 8 Jan 2025 > Screwdrivers Standardized by ASME/ANSI B107.600- 2021 for screwdrivers and screwdriver bits. Made for only one purpose, i.e. for loosening or tightening screws or screwhead bolts. A common screwdriver must fill at least 75 percent of the screw slot. Two types of recessed head screws in common use are: Phillips Reed and Prince. An example of a fastener which requires the use of a common screwdriver is the Airloc fastener which is used to secure the cowling on some aircraft. 9 Jan 2025  An offset screwdriver may be used when vertical space is limited The ratchet or spiral screwdriver 10 Jan 2025  External >Pliers Interlocking-joint (Water Pump) Pliers Needle-nose Pliers, Internal Slip-joint (Gas) Pliers Locking Pliers Internal Ring Pliers External Ring Pliers 11 Jan 2025 >Wrenches Allen Wrench, Box Wrench Open-End Wrench Adjustable (Crescent) Wrench Socket Wrenches Crowfoot-type Wrench Strap Wrench Torque Wrench 12 Jan 2025 Dimension of wrench and socket end > Selection of wrench size dependent on types of fastener to be tightened. > Width across flats is the distance between two parallel surfaces on the head of a screw or bolt, or a nut, mostly for torque transmission by positive locking. > The term width across flats (AF) is used for the following forms: 2-socket = round material with two surfaces 4-socket = profile square section 6-socket, 8-square = regular polygons Fastener terminology of hex nuts: > The width across flats indicates the nominal "size" of the d: Nominal thread diameter k: Wrench size (width across flats) spanner. It is imprinted on the spanners in millimeter (mm) h: Thickness values. Older British and current US spanners (wrenches) have e: Width across corners inch sizes that are imprinted in intermediate sizes in fractions. 13 Jan 2025  14 Jan 2025  Metric Bolt Torque Chart Imperial Flange Bolt Torque Chart 15 Jan 2025 > Socket Size Basic Knowledge In the diagram at right, the three key dimensions of a socket are labeled as Drive Hole, L, and S. These key dimensions determine the usage of this socket as follows: L indicates the overall socket length. The required length will be determined by the working environment. For screws in deep holes, a deep socket will be your best option. S indicates the target size of the nut which determines size of socket it requires. For example, it requires a 5mm socket for a 5mm nut. Drive Hole indicates the size of the drive hole (also referred to as the "driver hole" or "square hole"), which determines the torque size of the driver tool. For example, a ½-inch drive socket requires a ½-inch drive ratchet. 16 Jan 2025 > Socket Size socket sizes are divided into two systems: SAE (imperial, measured in inches) and metric (measured in millimeters). Both 6-point and 12-point sockets are measured using these two systems. The popular range is 5.5~24mm. SAE is used primarily in the United States and metric is used primarily in Europe and Asia. Conversion: 1 inch = 25.4mm Socket Length Sockets are available in deep, semi-deep and standard sizes. You can select the length most suitable for your working environment. The semi-deep size is designed specifically for 3/8" DR. 17 Jan 2025 > Punches For bench working such as making a hole on a metal work piece For making markings made by scriber or surface gauge permanent Generally made of carbon steel or tool steel. Used in combination with tools like a hammer and chisel to make them properly cut and shape. 18 Jan 2025 > Types of punch 19 Jan 2025 >Metal Cutting Tools Hand Files Hand Hacksaw Scraper Chisels Hand Snips Drills Hole Cutters Reamers Countersink Taps and Die 20 Jan 2025 > Bench Vice The bench vice is used to firmly grip the material or item upon which work is being done in a workshop. The vice must be secured firmly to the bench. To protect soft materials from the hardened, serrated, vice jaws, aluminium ‘vice clamps’ (or clams) can be positioned over the jaws. Other, special holding devices, such as ‘V’ blocks (made out of wood to protect tubular items) can be manufactured locally. 21 Jan 2025 >Hand Vice Classified by its overall length Can be used when splicing cables or holding small objects that are to be shaped or drilled. Small vice clamps can also be used with these vices when working with soft material. 22 Jan 2025 > Scriber Use for marking lines on the surface of metals. All scribed lines, on soft materials, must only be cutting (boundary) lines, and none must be left on the surface of the metal on completion > Dividers Use to set out distances and to scribe arcs and circles. 23 Jan 2025 > Torque Wrench Torque wrench shall be used to measure amount of torque, applying to a bolt or nut. Torque is rotational force applied around a point. Inch-pounds, foot-pounds, Newton- metres (N-m), etc. Torque = Force x distance between force applied and centre of fasteners When a extension may be used The actual amount of torque applied to a fastener when a five inch extension is used with 120 pounds of indicated torque is 150 inch-pounds. 24 Jan 2025 Metal Cutting Tools > Hand Files A Cutting tools for removing metal from a surface Most of the files are made of high carbon steel. The blade is hardened, whilst the tang (to which, a handle must always be attached, for safety reasons before the file is used), is left in a softer, tougher condition and is, therefore, less brittle. Hand files are classified by their: Length Shape Cross-section Cut Grade 25 Jan 2025 > Hand Files Length It is usually from 6 to 12 inches. The tooth coarseness increases as the length of the file increases. Shape Indicates the cross-section of the file, Usually rectangular, half round, round, square or three-square. Rectangular section files include both the mill file (always single cut) and the flat file (always double cut). Shape also refers to general configuration, that is, blunt or taper. Most files except very small files (6 inches and under) are blunt. 26 Jan 2025  The Cut Single cut files are generally used to produce a smooth surface or for finishing purpose. Double cut files are used for fast metal removal and where a rougher finish is permissible. Rasp cut is an extremely rough cut and is used mainly on wood, leather, hooves, aluminum, lead, and similar soft substances for fast removal of materials. Curved tooth file is used to produce a very smooth finish on soft metals such as aluminum. 27 Jan 2025  The coarseness – it is measured differently, depending on whether the file is American or Swiss-made. American hand files typically feature three grades of coarseness (ie bastard cut, second cut and smooth cut). Swiss files come in seven grades of coarseness ranging from 00 to 6. Coarse – roughest cut for rapid removal of materials. (very seldom used) Bastard – quite coarse, primarily for roughing out, but may be used for the entire work, if the finish is not important. (most often used) Second cut – intermediate grade, give a better surface finish to the work, but are slower cutting. (widely used), Smooth – finest cut to produce very smooth surfaces, be used for finishing work only. (rarely used) 28 Jan 2025  29 Jan 2025 > Hand Files - Care of Files Cleaning the File File teeth can become clogged with chips between them. This causes the file to slide over the work instead of cutting. This condition is known as pinning. The pins or chips in the file teeth may be removed with a file brush or file card. Rubbing chalk between the teeth prevents pinning and produces smoother finishes. A brass or copper bar pushed parallel across the teeth from edge to edge removes the pins. An impression of the file teeth is cut into the bar, thus removing the pins. 30 Jan 2025 > Hand Files - Care of Files Installing a File Handle Insert tang end into socket in handle. Using hand pressure, tap handle repeatedly on bench top until file is firmly seated. Do not hammer file into handle. Removing a File Handle Hold file with one hand and handle with the other, with handle upward. Pull the file from the handle while striking the ferrule (metal part of handle) lightly against the edge of the bench. 31 Jan 2025  File Handling Precautions Do not toss files in drawers or tool boxes where they can rub against each other and against other tools. Store them in separate holders or in holes cut in a block of wood or hang them up. Never use a file without a securely attached handle. Never use a file for any purpose other than filing. Do not oil a file; this will cause dulling. If a finer finish is needed, use a finer cut. Never strike a file against a vise or other hard object to remove chips. Keep files clean and sharp. 32 Jan 2025 > Drill Bits A drill bit is a cutting tool used in a drill to remove material to create holes, almost always of circular cross-section. Drill bits come in many sizes and shapes and can create different kinds of holes in many different materials. > The main parts and features of a drill bit include: Brad point – the front section of the drill that cuts into the material. Spur – it is the centre of the drill bit’s point. Cutting edge (lip) – the part right at the tip of the point, removes the material as the bit advances Flutes – also called the channel, the flutes are the section just past the cutting edge. Shank – attaches the drill bit to the drill. 33 Jan 2025 > Types of Drill Bits – drill bits are designed according to the applications. Below figures show common types of drill bits. 34 Jan 2025 > Twist Drills The twist drill bit is the type produced in largest quantity. The Morse-type (named after its inventor, an American engineer) of Twist Drill is the one most commonly used in aircraft (and in general) engineering. Drill diameter is called out by one of three size standards or series: factional, letter, and number. The table shows the lists the decimal equivalents of drill sizes. 35 Jan 2025  36 Jan 2025 > In order that the drill will cut properly, the drill point (drill angle) must be ground to the correct shape. The most common cutting angles for drills are 118° and 135°, a clearance angle of 12° and a web angle of 130°, are typical for normal metal cutting, such as aluminium alloys, steels, cast iron and copper. These can be changed to suit the cutting of different materials such as harder metals, softer metals or plastics. > Other considerations in the use of twist drills Use only a sharp drill with the correct point angle. Never use a drill that is bent. Never use a drill that has a burred shank. Use the shortest drill practical for the job. Rule of thumb: use a drill bit with larger cutting angle on a harder material 37 Jan 2025  The use of a suitable lubricant when drilling is very important, not only does the use of lubricant improve the quality of the hole, but it also assists in dissipating the heat produced by drilling. This improves the cutting efficiency and prolongs the life of the drill. Outgoing lubricant helps to bring metal chips out. For a twist drill to cut efficiently it must rotate at the correct speed. In a particular metal, for a given diameter drill. Most hand drills (excepting Breast Braces) are limited to one speed, which is a compromise on the ideal speed for the material and for the drill size. The speed of most static drilling machines can be varied by means of a gearbox or variable drive belt/pulley arrangement. 38 Jan 2025 Common Power Tools > Powered tools have to be treated with respect because they can injure, and in exceptional cases, can cause death if they are incorrectly operated. Before using any powered machine/tool, personnel must make sure that: User have been properly trained and are currently authorised to use it All protective guards and fences are securely in place No part of the body or clothing can come into contact with moving parts Protective clothing is fastened and neck ties (if worn) tucked in or removed All rings and other jewelry are removed Safety glasses/goggles are worn wherever there is a debris risk Where necessary, the appropriate fire extinguisher is readily to hand A safety mat is available to stand on where electrical machinery is used Machinery is checked for any “Warning” notices indicating it is unsafe for use. 39 Jan 2025 > Electrical-powered Tools Electrical-powered tools require additional regular maintenance to the parts of the electrical motor. The motor bearings and gear section must be properly lubricated. The brushes and armature must also be kept in good order. The motor is air cooled and must be kept free of dust and dirt to prevent overheating. The electrical motor can burn out if stalled for an extended time. Use the manufacturer's recommended procedures for care and maintenance of all powered tools. > Air-powered Tools Air-powered tools are driven by an air motor built into the tool. The air is supplied to the turbine motor by an air compressor through a suitable control valve and hose. Air powered tools run cooler than electrical tools. They also are safer because there is no chance of electrical shock or sparks. Clean, dry filtered air must be used. Air tools must be properly lubricated and cleaned to prevent rust and corrosion to the internal parts. Air powered tools can be stalled without damage to the tool. Air powered tools are widely used in aircraft maintenance work because it is safer, especially in avoiding electrical and fire hazards. 40 Jan 2025 Precision Measuring Tools > Precision Measuring Instruments are provided to measure dimensions to a greater accuracy than can be obtained by the use of a simple engineer’s rule. > Where the smallest graduation on a rule is usually either 1 mm or, perhaps, 1/64", precision instruments are available which measure to > 0.01 mm or to 0.0001” (1 dial = 1-thousandth inch) > The precision instruments mentioned here would normally be found either in a workshop environment or in a ‘clean room’, which may be part of a company’s Quality Department. > It should also be noted that, whilst very basic forms of the different instruments are described, in order that the principles of operation be understood, the actual precision instruments, found in workshops and ‘clean rooms’ may appear quite different and, in all probability, will possess digital readout facilities. 41 Jan 2025 > External Micrometers Use for measuring (or testing the level of accuracy of) the external sizes of objects. 42 Jan 2025  Procedures of using micrometer for outside diameter measurement. Make sure the micrometer is adjusted accurately to zero or set to a know standard gage. Hold the anvil of the micrometer against the workpiece. Rotate the thimble until both anvil and spindle lightly contact the workpiece. Turn the ratchet until it slips and clicks, it indicates a proper contact pressure is made for the correct reading. Reading the micrometer Metric and Imperial micrometers (while their units of measurement are different), are operated in a similar manner. The Metric micrometer uses a thread pitch and, thus, a lead, of 0.5 mm (two threads per millimetre), so that the thimble moves over the barrel a distance of 0.5 mm per revolution. The fiducial line, on the barrel, is marked in increments of 0.5 mm and 1 mm, with numerals at intervals of 5 mm (5, 10, 15, etc.) to 25 mm. 43 Jan 2025 > Other Micrometers Micrometer depth gauges are used to measure the depth of holes, slots, and projections accurately. It should be noted that it reads in the reverse of an ordinary micrometer. Inside micrometer consists of a micrometer head and interchangeable extension rods. The distance between ends or contacts can be changed by turning the sleeve on the micrometer head. It is used to measure large internal size. 44 Jan 2025 > Vernier Calipers The Vernier caliper is one of the precision measuring tools of accuracy up to 1/1000 of an inch. Metric Vernier caliper can read up to an accuracy of 0.02 mm. The Vernier caliper consists of a graduated steel bar with a fixed jaw at one end. A movable jaw sliding along the bar has a graduated Vernier scale so that it can be compared with the fixed scale on the bar. 45 Jan 2025 > Vernier Calipers Procedures of using Vernier calipers for outside diameter measurement. Open the caliper slightly wider than the size of the rod. Tighten the adjusting nut clamp screw. Make sure the caliper is square across the workpiece. Turn the adjusting nut to bring the movable jaw into contact with the workpiece, it should be noted that the jaws should just drag lightly across the workpiece for a correct reading 46 Jan 2025 Lubrication > Lubrication is a process for reducing friction and wear, through the introduction of lubricant between two moving surfaces. > The materials, commonly used for these purposes, are greases and oils and this topic discusses the various methods and equipment used in the lubrication of aerospace mechanisms. > A large number of different greases and oils are in use in aircraft maintenance. > All lubricants should be kept clean and covered to keep out foreign objects. The correct quantity of the respective lubricant must, always, be used, as over lubrication may cause all manner of problems, from contamination of electrical and mechanical equipment, to dirt and dust collecting on the lubricant residue. > Care must also be taken that lubricants do not remain in prolonged contact with unprotected skin (and particularly eyes) as many of them are severe irritants and present serious hazards to health. Hot oil also constitutes a danger to personnel. 47 Jan 2025 > Grease is the preferred lubricant, in certain circumstances, for the reasons: Where conditions are dirty, dusty or wet, grease will provide a sealing medium, which will tend to prevent the entry of foreign matter into moving parts Grease will stay in vertical bearings, whereas oil will drain away Grease, packed into a bearing or housing, will provide sufficient lubrication for prolonged periods of time Grease lubrication systems use much cheaper fittings, and less complicated designs than those required for oil systems. > Grease, however, has limitations in certain situations, in that grease: Cannot replace oil when heat needs to be carried away Cannot be used where contamination is likely to occur Cannot be used where debris and contaminants have to be washed away. 48 Jan 2025 > Oils are also required to remain chemically stable and to possess (and retain) a suitable viscosity during their useful life. In general, every oil must: Adequately wet the surface needing lubrication Not evaporate too much in service Not produce gum, sludge or carbon Not damage the material with which it normally comes into contact. > Oil provides lubrication in two distinct phases, which are referred to as: ‘Boundary’ lubrication ‘Fluid’ lubrication. 49 Jan 2025 > Lubrication Equipment Because of the numerous types of lubricants that are available, the equipment used for applying those lubricants is vast and so mention is made here of only some of the more typical equipment, which includes; Grease Guns Oil Cans Risbridger Replenishing Rigs. 50 Jan 2025 > Generally, lubricating oils do not deteriorate during storage, but low- temperature greases can suffer and must be stored in a cool place. > If water gets into either type of lubricant, the result can be very serious. Water contamination can cause: Breakdown of normal properties under bearing loads Oil additives rendered ineffective, giving a tendency to ‘sludge’ Failure of normal properties due to oil emulsification Frothing of engine oil, which can cause excessive loss of oil through the system vents. Many contaminants, such as rust and dust in suspension, may lead to blocking of oil passages or damage to moving parts. > In grease, these solids produce a sort of grinding paste, which wears moving parts very quickly. > When oils and greases are in storage, key points are: All containers have their lids firmly secured at all times when not in use The majority of lubricants need to be stored in a cool place Different types or groups of lubricants must be kept apart, to prevent a risk of cross- contamination Jan 2025 All equipment must be kept totally clean. 51  Questions ? 52 Jan 2025