Aviation Standards of Workmanship PDF

Standards of Workmanship Workmanship Workmanship is the degree of skill with which a product is made or a job done. Within the aircraft maintenance environment, it is a term that takes into account the following factors: The art of skill of a worker. The quality of the product. The product or result...

Standards of Workmanship Workmanship Workmanship is the degree of skill with which a product is made or a job done. Within the aircraft maintenance environment, it is a term that takes into account the following factors: The art of skill of a worker. The quality of the product. The product or result of the labour and skill of a worker. Attitudes of the AME, team and organisation. Duty of care (self). Duty of care (others). Duty of care (equipment). Working done according to a standard. Workmanship is important for an AME - people put their lives in the hands of AME's every time they fly 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 18 of 498 Standards of Workmanship Standards are so much a part of our daily routine that we use them without even being aware of doing so, and without giving thought to how they are created or the benefits they provide. A standard is an agreed way of doing something. It can be recorded and published formally, or may simply be a company's informal unwritten procedure. Standards provide benefits to business and to individuals, by defining accurate measurements and lowering production costs; improving product performance, quality, uniformity, interoperability and functionality; and providing a method to improve health, safety, the environment, communications, competition, international trade, and improving the quality of life. Examples of standards may be one of the following types: Private standards are only used by the organisation that developed them. National standards (e.g. Australian Standards [AS]) are produced by a country's National Standards Body (NSB). In Australia, standards are developed together with industry, government and society. Most standards are enforced by regulation and some are voluntary. International standards are produced by the International Organisation for Standardisation (ISO), whose members are the national standards bodies of countries all over the world. Documented standards consult several stakeholders 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 19 of 498 Tool Control Care of Tools Tools are designed to make a job easier and enable you to work more efficiently. If they are not properly used and cared for, their advantages are lost to you. Regardless of the type of work to be done, you must have, choose and use the correct tools in order to do your work quickly, accurately and safely. Without the proper tools and the knowledge of how to use them, you waste time, reduce your efficiency and may even injure yourself or others. Tools are expensive and vital equipment. When the need for their use arises, common sense plus a little preventative maintenance prolongs their usefulness. Tool control 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 20 of 498 In general, the following precautions for the care of tools should be observed: Use each tool only for the job it was designed to do. Each type of tool has a specific purpose. If you use the wrong tool when performing maintenance or repairs, you may damage the equipment you are working on or the tool itself. Remember: Improper use of tools results in improper maintenance. Improper maintenance results in damage to equipment and possible injury or death to you or others. Never leave tools scattered about. Always avoid placing tools on or above machinery or on electrical equipment. Never leave tools unattended where machinery or aircraft engines are running. When they are not in use, stow them neatly on racks or in toolboxes. Never use damaged tools. A battered screwdriver may slip and spoil the screw slot, damage other parts or cause painful injury. A gauge strained out of shape results in inaccurate measurements. Clean tools after each use. Oily, dirty and greasy tools are slippery and dangerous to use. Conduct a thorough inventory of tools after use to prevent loss. Remember: The efficiency of aircraft maintenance engineers and the tools they use is determined to a great extent by the way they keep their tools. Likewise, you will be frequently judged by the manner in which you handle and care for your tools; anyone watching will notice the care and precision with which you use the tools of your trade. The care of hand tools should follow the same pattern as for personal articles, that is, always keep hand tools clean and free from dirt, grease and foreign matter. After use, return tools promptly to their proper place in the toolbox. Improve your own efficiency by organising your tools so that those used most frequently can be reached easily without digging through the entire contents of the box. Avoid accumulating unnecessary junk. Tool Control It is a matter of fact – tool control affects safety. When a tool is misplaced on the job, the repercussions can be as minor as investing the dollars to replace it, or as major as the permanent damage that occurs to an engine or aircraft. However, what about the safety risk? The National Aerospace FOD Prevention Inc. estimates the cost of foreign object damage (FOD) to the global aerospace industry at $4 billion annually. These dollars are spent largely repairing aircraft engine damage caused by the ingestion of foreign objects from runways. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 21 of 498 Realising this, in an effort to prevent the problem of FOD caused by misplaced tools and the possible cost involved, most aircraft maintenance organisations establish and enforce a Tool Control Program. Tool control procedures are governed by the organisation’s Maintenance Organisation Exposition (MOE), which must be approved in accordance with the CASR 42, 145 and 145 MOSs. The MOE must detail all management procedures for tooling, distribution and return of tooling after use. The issue of tools includes: Record of user; Location of use; and Verification that the aircraft or component is clear of all tools after completion of maintenance. Aviation Australia utilises a shadow-board-and-tool-tag tool control system whereby instructors and trainees are issued a number of ‘tool tags’ and a tag is placed on the ‘shadow’ when a tool is removed. Once the trainee is finished using the tool, it is placed back on the shadow board and the tag is retrieved. Like all good systems, it relies on the honesty and integrity of the workforce to make it a success. The goals of a Tool Control Program are as follows. Objective The primary objective of a tool control program is the safety of personnel and the prevention of aircraft damage which may result from: Lost tools; Damaged hardware; and Miscellaneous rubbish. Responsibility The primary responsibility for the control of tools is with the user. Management should ensure adequate procedures are in place to assist with the control of company and personal tools: Area control; Tool identification; and A FOD critical zone/area. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 22 of 498 Area Control Helps Tool Control Areas where work controls are implemented should be designated by: Appropriate signs; Floor striping and access; Limitations on personnel required to perform tasks; and A system accounting for all items entering or removed. Identification of Tools Only tools that have been permanently identified should be allowed or used in a tool control area. This may include colour coding, engraving or other prominent markings. © Aviation Australia Tool order and placement 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 23 of 498 Tool Control and Foreign Object Damage FOD Critical Zones/Areas Be aware of where you are working. For example, are you working on or near flight controls or engine controls or near engine inlets? Will misplaced tools be a hazard to the safe operation of the aircraft? Control in FOD Critical Areas All items taken into FOD critical areas must be accounted for. Employees’ personal tools should be documented on a tool list, and tools should be transported in a bag or small case. Whether you use tools from a tool board or operate from your own toolbox, a Tool Control Program should be designed and implemented to track tools from the minute they leave the tool board or toolbox to the moment they are returned. For different workplaces, the details of tool control can vary depending on the needs and parts the workshop uses, but usually the basics remain the same. Foreign object damage 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 24 of 498 Individual Toolboxes Individual toolboxes, at a minimum, should have a method to quickly determine that all tools are accounted for at the end of a maintenance task. This can only be done if each tool has a specific storage location that allows for quick identification if the tool is missing. One method utilises custom foam toolbox inserts that allow technicians to instantly see if a tool is missing. When a tool is removed for use from its perfectly shaped resting place that matches its size, a colour (yellow or red) is revealed beneath to signal that it is out of the toolbox. As long as the top colour of the foam (blue or black) is visible, all tools are present. The foam can be sized to fit any toolbox, and it has the added benefit of reducing tool damage due to improper storage. Individual toolboxes 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 25 of 498 Shadow Boards Shadow boards are one of the most popular forms of visual management tool control. Many aviation organisations are installing shadow boards, or boards marked with the shapes of tools, to indicate proper tool locations. The shadow board visually conveys two pieces of information: Where the tool belongs Whether the tool is missing from its designated location. This at-a-glance visual indicator can be a real time saver, as it eliminates the need to search through toolboxes, tool drawers or cabinets to find a tool. Posting the shadow board in plain sight of all who use the tools provides immediate feedback as to the status of the tool. Some organisations have taken the shadow board concept a step further by introducing colourcoding. The shadow boards themselves are painted a certain colour, and a matching colour is applied to the tools that belong on them (usually either with paint or durable tape). Typically, each work area is assigned a dedicated colour for its shadow board and tools. One area, for example, may have blue colour-coded tools, another red colour-coded tools and yet another black colour-coded tools. In such a system, it is easy to see if a tool is in the wrong location because a black tool on a red tool board stands out. Photo by Cesar Carlevarino Aragon on Unsplash Tool order and placement - shadow boards 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 26 of 498 Tool Identification Some maintenance organisations require employees to permanently mark their tools for identification purposes. This provides a way to quickly identify a tool’s owner when one is found. Tools can be marked using a Vibra Peen tool or laser etching. Some other marking methods, such as permanent marker, may not be very effective in a hangar environment. Tool identification - laser etching If your company requires mechanics to mark their personal tools in a uniform method, consider the requirement carefully. For example, it would be better to use engineers’ initials as a tool identification marking rather than company-specific numbers such as employee numbers. If you change to another company, these numbers will not be relevant and you may have to mark them all over again. If employees are required to mark their personal tools, it can be useful to maintain a tool identification log in a central location (Maintenance Control or Quality Assurance, for instance). This log could list all the employees and the identification they are using to mark their tools. This way, if a tool is found, the log can be referenced to find out who owns it. Marking tools serves two purposes. First, it ensures that a found tool is returned to the owner. Second, it helps ensure compliance with missing tool reporting. It makes employees more vigilant in reporting missing tools instead of just going to the closest tool truck or store to buy a replacement. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 27 of 498 Tool Inventory A tool inventory should be accomplished regularly so that any missing tools can quickly be identified and searched for before they affect the safety of an aircraft. This can be done after each work task or at least once a day. Many aircraft maintenance organisations choose to do it at the beginning and end of each shift. Tool inventory 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 28 of 498 Missing Tool Reporting An important part of any tool control program is a process for missing tool reporting. In order to achieve the goal of accounting for all tools to ensure a safe product for the customer, the maintenance culture must encourage employees to report any missing tool. This procedure should be clear about how often tools need to be inventoried, how employees should report a missing tool and the steps to be taken once a missing tool is reported. An important part of this is designating the person who has the authority to release the aircraft in the event a missing tool is not found. Missing tool reporting 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 29 of 498 Workshop Practices Workshop Materials Many types of workshop materials are available. These include: Greases Oils Solvents Sealants Contact cements Paints Paint strippers. It is important to ensure that a Material Safety Data Sheet (MSDS) and a specification sheet are available for all materials used in the workshop. Workshop materials 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 30 of 498 Material Storage Storage of flammable materials is an important factor when ensuring safety and maximum usage. Flammable materials such as solvents, paints, paint strippers, contact cements, greases and oils should be stored in an appropriate flammable storage facility when not in use. Some materials are highly toxic, so it is vital to comply with the MSDS for individual materials. This involves, among other things, using PPE and working in a well-ventilated environment. Toxic materials Many aircraft sealants require refrigerated storage to ensure they stay usable for their shelf life. It is important to check the expiry date/shelf life before use. Failure to do so could compromise the integrity of the job being performed. When you have finished using the product, always ensure the container is properly sealed to enable its re-use at a later date. Mixed two-pack sealants need to cure completely before disposal, and then they can be disposed of in accordance with local council/authority regulations. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 31 of 498 Sealants 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 32 of 498 Dimensions, Tolerances and Allowances Dimensions Most aircraft drawings are dimensioned using a reference edge from which all dimensions are made. There are two ways of placing dimensions on an aircraft drawing: 1. Write all dimensions perpendicular to the dimension lines. 2. Write all dimensions parallel to the bottom of the drawing (more conventional method). Dimensions The illustration shows a typical layout of an aircraft drawing. The nominal dimension of an aircraft part is the size stated on the drawing. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 33 of 498 Sheet Metal Working A part fabricated from aircraft sheet metal has a maximum and a minimum allowable size. The part is considered acceptable if its size falls within that range. Please note that the double prime symbol (″) represents inches in drawings and dimensional specifications. Tolerance is the difference between the nominal dimension and the upper and lower limits of size, e.g. if the nominal dimension is 5.300 in. and the upper and lower limits are +0.010 and -0.010 in., then the tolerance is said to be ±0.010 in. (± means plus or minus). This tolerance can also be expressed as 0.020 in. This is the upper limit of size minus the lower limit of size (5.310 in. – 5.290 in. = 0.020 in.). In aircraft drawings, any dimension given as a common fraction normally assumes a dimension tolerance of ±1/64 in. Allowance for sheet metal work is the difference between the nominal dimension of a part and its upper limit OR lower limit. The examples below of upper limit and lower limit allowance specify the same dimensional values as above. Upper limit allowance: 5.300 in. + 0.010 in. – 0.000 in. OR Lower limit allowance: 5.300 in. + 0.000 in. – 0.010 in. Precision Cylindrical Parts A precision cylindrical part (e.g. close-tolerance bolt) has a maximum and a minimum allowable size. The part is considered acceptable if its size falls within that range. However, the acceptable range is usually much smaller for mating cylindrical parts than it is for sheet metal repairs. Bolt tolerances 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 34 of 498 Tolerances and Allowances Tolerance Tolerance is the difference between the nominal dimension and the upper and lower limit of size, e.g. if the nominal dimension is 0.3125 in. and the upper and lower limits are +0.0005 in. and -0.0005 in., then the tolerance is said to be ±0.0005 in. This tolerance can also be expressed as 0.0010 in. This is the upper limit of size minus the lower limit of size (0.3130 in. – 0.3120 in. = 0.0010 in.). Allowance For fits between mating cylindrical parts, allowance is the prescribed difference between the maximum material limits of mating parts. A maximum material limit is the limit of size that provides the maximum amount of material for the part, e.g. the maximum limit of diameter of a bolt and the minimum limit of diameter of its hole. Tolerance Allowance Tolerance Hole Shaft Lower limit Lower limit Upper limit Upper limit © Aviation Australia Allowances and tolerances If the maximum diameter of the bolt is 0.001 in. less than the minimum diameter of the hole, there is a minimum ‘clearance’ of 0.001 in. This is a positive allowance. If the maximum diameter of the bolt is 0.001 in. greater than the minimum diameter of the hole, there is a maximum ‘interference’ of 0.001 in. This is a negative allowance. Note: Tolerance, allowance and types of fit (including clearance and interference fits) are discussed in greater depth in 7.5 and 7.6. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 35 of 498 Calibration Standards Precision Tools and Test Equipment Aircraft maintenance organisations are required to regularly inspect and calibrate their precision tooling and equipment. A clear system of labelling indicates to users that the item is within the inspection or calibration period. The label should show: The date last tested When the next inspection or calibration is due, and The authorised person’s signature or stamp. Also, a register should be maintained for all precision tooling and equipment, together with a record of the calibrations and standards used. Inspections and calibrations should be done in accordance with the manufacturers’ instructions except where the organisation can show by results that a different time period is appropriate. Usually, this involves inspections and calibrations being conducted at more frequent intervals but rarely at less frequent intervals. Measuring Equipment Because accurate measurement is essential, engineers and technicians must learn to use various measuring tools correctly and efficiently. Before using a precision measuring tool, ensure that it is within its calibration period for required accuracy checks. (Refer to the calibration tag.) The tool must be calibrated by an approved person or organisation and have a prescribed life limit between calibrations. Before use, it is necessary to ensure the tool will ‘zero’ correctly. It is an offence in the regulated civil aviation industry to use personally owned measuring tools unless they are maintained by an approved organisation and the aircraft operator or maintenance, repair and overhaul (MRO) organisation agrees to the use of such measuring equipment. 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 36 of 498 Torque Wrenches Torque wrenches are precision measuring tools and should be periodically checked for accuracy – calibration. This is achieved using a torque analyser, which is a mechanical loader that applies a true force at 90° to ensure maximum accuracy. Calibration of torque wrenches and other measuring equipment is carried out by manufacturer-approved organisations employing certified technicians. © Jeppesen Torque wrenches 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 37 of 498 Pressure Gauges and Transmitters Pressure gauges and transmitters are calibrated by hydraulic pumps which use either water or oil, or by pressure generators that use oil or gas. Pressure gauge tester 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 38 of 498 Micrometers It is possible for a micrometer to slip out of calibration; however, most micrometers can be recalibrated by inserting a precision block – test piece – between the anvil and the spindle. The micrometer is then carefully calibrated by rotating the sleeve with a special wrench until its longitudinal line exactly aligns with the zero mark on the thimble. Note that temperature extremes during the day can affect the calibration process. © Jeppesen Micrometers outside 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 39 of 498 Calibration Tags Upon completion of calibration checks on all precision tools, a calibration label or tag should be attached to the tool. The label or tag should always be checked prior to using the tool. Calibration labels 2023-11-24 B-07b Maintenance Practices CASA Part 66 - Training Materials Only Page 40 of 498