Aircraft Maintenance practices introduction

Aircraft Maintenance Engineering

Maintenance Practice-I First SemesterBy-Gaurav

Maintenance

The process of keeping something in useable condition by checking or repairing it on regular basis.

Maitenance Practice-1

Practice

Actual doing of something rather than ideasWay of doing something Doing an activity or training on regular basis to improve skillsHabit or CustomMaitenance Practice-1

Maintenance Practice

This subject deals with the way of keeping something in useable/good condition

aircraftAirworthy condition


Why this subject?Prime objective of an AME is to maintain an aircraft in airworthy condition so that it can fly safe and reach its destination with all its passenger safely.If there is an error in maintenance or ignorance of maintenance procedure by maintenance personnel then the life of passengers and crews and machine is at stake.So it is important that the persons involved in maintenance of aircraft must have proper knowledge of procedures and practices involved in maintenance of aircraftMaitenance Practice-1

Maintenance Practice

This Subject is divided in 03 partsMaintenance Practice -1- Ist SemesterMaintenance Practice -2- IInd SemesterMaintenance Practice -3-IIIrd Semester


Maintenance Practice-1Safety Precaution-Aircraft and WorkshopWorkshop PracticesToolsOperation, Function and Use of Electrical General Test EquipmentFits and ClearancesWeight and BalanceMaitenance Practice-1

Chapter-1Safety Precaution Aircraft and Workshop


Safety PrecautionAn action taken in advance to protect against possible danger, failure, or injury.Maintenance Practice-1

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AircraftAny machine which can derive support in the atmosphere from reactions of the air other than reactions of the air against the earth's surface and includes balloons whether fixed or free, airships, kites, gliders and flying machines. (source: Aircraft Rules 1937)Any vehicle designed to be supported by air, heavier or lighter than air, mechanically or non-mechanically driven

Maintenance Practice-1

WorkshopA room or shop where work is done

It includes -Aircraft hanger maintenance bays-Mechanical and electrical bays-Machine shops -Cleaning plants-Battery rooms-Basic bench tool work areas


AccidentAn unfortunate incident that happens unexpectedly and unintentionally, and may result in injury or death of people and/or damage to equipments or facilitiesAccident always have a cause.That cause may be -unsafe human condition-unsafe environmental condition (Humans are responsible for choosing or creating unsafe condition )


Hazardanything that has the potential to create danger and thus harm.

Most hazards are dormant or potential, with only a theoreticalriskof harm; however, once a hazard becomes "active", it can create anemergencysituation.

HazardHazards occurs as a result of day-to-day activities in and around the workplace. e.g. Slippery floorDefective toolsSpilled chemicalsOverconfidenceFatigueStressLack of fitnessInappropriate or incorrectly worn dresses

Riskrisk is the likelihood/chance that a person may be harmed or suffers adverse health effects if exposed to a hazard. The level of risk is often categorised upon the potential harm or adverse health effect that the hazard may cause, the number of times persons are exposed and the number of persons exposed.Exposure to airborne asbestos fibres will always be classified as high because a single exposure may cause potentially fatal lung disease, whereas the risk associated watching a television for a short period could be considered to be very low as the potential harm or adverse health effects are minimal.

Risk and HazardThe terms Hazard and Risk are often used interchangeably but this simple example explains the difference between the two.

If there was a spill of water in a room then that water would present a slipping hazard to persons passing through it. If access to that area was prevented by a physical barrier then the hazard would remain though the risk would be minimised.

So, Risk and Hazard collectively leads to Accident.

Risk Assessment for Safety

A risk assessment would involve identifying a hazard and then evaluating the risk in the light of precautions to reduce the danger or remove it.

First hazard must be recognized; then they must be assessed; and finally, if necessary, they must be controlled.

Recognition of HazardSlippery floorsUntidy work areas Cluttered walkways Insecure handrailsDefective toolsSpilled chemicalsInadequate lightingPoor ventilationLack of equipmentExcessive noise

Unsafe Environmental Condition

Recognition of HazardAPATHYBOREDOMNEGLIGENCECOMPLACENCYDISOBEDIENCETOMFOOLERYSHOWING-OFFOVER CONFIDENCEFATIGUESTRESSLACK OF FITNESSINAPPROPRIATE OR INCORRECTLY WORN DRESSESLONG HAIR DRUG AND ALCOHOL ABUSE

Unsafe Human Condition

Safety Precaution- AircraftMaitenance Practice-1Airport Terms

AirportAnairportis a location whereaircraft such asfixed-wing aircraft,helicopters, andblimpstake off and land. Aircraft may be stored or maintained at an airport. An airport consists of at least one surface such as arunwayfor a plane to take off and land, ahelipad, or water fortakeoffsandlandings, and often includes buildings such ascontrol towers,hangarsandterminalbuildings.Maitenance Practice-1

Airside and LandsideAirports are divided into landside and airside areas. Landside areas includeparking lots,public transportationtrain stations and accessroads. It is the area accessible to normal public.Airside areas include all areas accessible to aircraft, including runways,taxiways andramps. Access from landside areas to airside areas is tightly controlled at most airports.


Airside and LandsideMaitenance Practice-1

Airside and LandsideMaitenance Practice-1

APRONArea that accommodates aircraft for the purpose of loading/off-loading passengers and cargo, refueling, parking and maintenance.


APRONMaitenance Practice-1

APRONTarmac: Though commonly used to describe the area where planes park,tarmacisnt officially a place. That word is the name of a product produced by a British company that produces a surface coating that is applied to roads and airfields.Using tarmac to describe where planes park is like calling the area outside a building where cars park the concrete instead of calling it the parking lot. Tarmac with a capital T is a registered trademark.Maitenance Practice-1

APRON

Ramp: Its a common unofficial term that is very much in use at airports of some American and Asian countries.Maitenance Practice-1

APRON

Apron: This is in fact the official term used by both the International Civil Aviation Organization (ICAO), which advises on aviation practices worldwide, and the Federal Aviation Administration (FAA), which regulates aviation in the U.S., to designate the area at the airport where parked and serviced at airports.

The apron is a busy place. Its the part of the airport where vehicles and airplanes share the same space. The many movements on the apron are not generally controlled by the air traffic control tower. Maitenance Practice-1

Maneuvering AreaArea other than apron, used for the movement of the aircraft on the ground and for the taking-off and landing.


Movement AreaComprises both the maneuvering area and the apron.


TaxiwayPath connecting the runway to other aircraft facilities, such as hangers and apron.Maitenance Practice-1

RunwayA strip of land or water from which aircraft can takeoff and land on airport.Maitenance Practice-1

HangerAn enclosed structure designed to hold the aircraft in protective storage. Maitenance Practice-1

Points to be Observed Apron environment is often a busy one and be aware of the danger.

Aware with airport operations instructions rules.

Entry to the maneuvering area require clearance from local air traffic controller.


Airport MarkingAirport markings are used to mark structures, and path so that these can be used by required personnel or vehicles without confusion.

Both paint and lights are used for marking so that, markings are visible in day as well as night.

Vehicle routes white lineAircraft routes yellow linePedestrian routes green line Delineation between apron and maneuvering area double white lines


Aircraft TaxiwayThe taxiway centre-line is a single continuous yellow line, 6 inches (15 cm) to 12 inches (30 cm) in width. This provides a visual cue to permit taxiing along a designated path. Taxiway edge marking are of two types:Continuous: Consist of a continuous double yellow line, with each line being at least 6 inches (15 cm) in width spaced 6 inches (15 cm) apart. They are used to define the taxiway edge from the paved surface not intended for use by aircraft.


Aircraft TaxiwayDashed Markings. define the edge of a taxiway or taxi-lane on a paved surface where the adjoining pavement to the taxiway edge is intended for use by aircraft. e.g., an apron. Dashed taxiway edge markings consist of a broken double yellow line, with each line being at least 6 inches (15 cm) in width, spaced 6 inches (15 cm) apart (edge to edge). These lines are 15 feet (4.5 m) in length with 25 foot (7.5 m) gaps.

Identified by blue edge light and sometimes green centre line lights.

Also have red stop bar lights at various holding points.


Aircraft TaxiwayMaitenance Practice-1

Runways


ApronMaitenance Practice-1Normally illuminated by an array of overhead pylon lights.

RunwaysA line of lights on an airfield or elsewhere to guide aircraft in taking off or coming in to land or an illuminated runway is sometimes also known as aFlare Path. Runway center Line: embedded in surface of runway at 50 ft interval along runway center line. White light is used for this except last 900 m, alternate white and red for next 600m, and red for last 300m.Runway edge lights: white elevated lights that run the length of the runway on either side. On precision instrument runways, the edge-lighting becomes yellow in the last 2,000ft (610m) of the runway, or last third of the runway, whichever is less.Maitenance Practice-1

VehiclesFor driving in the movement area personnel must require Airfield Driving Permit (ADP).Aircraft have priority over all vehicles in the airside.Fire and rescue vehicles on emergency call out have priority.Pedestrian have priority on apron.


VehiclesAll vehicles display a roof mounted yellow flashing obstruction light in movement area.Fire and rescue vehicles display a flashing blue light when emergency callout.In apron speed of vehicles restricted to 15 mph.Vehicles use dipped headlight while moving .Vehicles must not approach aircraft until the aircraft is choked and engines have been shut down and anti-collision lights have been switched off.


VehiclesVehicles have to positioned so that they do not have to reverse in order to leave the zone. Maitenance Practice-1

ClothingWear approved high visibility anoraks or tabards at all times.Maitenance Practice-1

NoiseNoise from turbine engine can cause temporary or long-term damage to hearing. This noise also blankets the sound of approaching vehicles and will drown out shouted warnings.Personnel working on airport needs to wear the ear defenders.


EngineMaitenance Practice-1Personnel must be alert at the time of starting of engine not to stray in front of engine intakes, propellers or into the jet-blast.Even at low power setting hot jet blast can be left 100ft behind the aircraft.At full power some engines can even pull a full grown man into intake. And can throw a truck, if is in the vicinity of engines exhaust.So areas coming directly under the operation of engine should be avoided.

Engine


EngineVideoMaitenance Practice-1

Fuel SpillThe source of spill should be shutoff .All sources of ignition should be removed.All engines in Ground Power Unit and vehicles in the area should be turned off.Maitenance Practice-1

Task LightingOverhead pylon lights are capable of illuminating the area but this does not help when personnel are working under aircraft.Lighting in these area are well below what would considered adequate for conducting maintenance task.Hand torches may seem to be an ideal solution but their batteries gradually deplete and they do restrict user to one handed operation.


Task LightingEnsure that the light being used during maintenacne is of approved flameproof type.


Foreign Object Damage (FOD)Unwanted object other than objects required aircraft maintenance and operation are known as Foreign Object. Cuts of locking wire, split pins, plastic bags, stones etc. Can damage the turbine engine.Can cause serious damage to the moving propeller blades.


Working on A/cAppropriate clothing and suitable footwear, do not wear jewellery or loose items.Dont carry means of ignition.Be aware that it takes time to gain fully night vision when moving from a brightly lit area to a dark place.Always ground aircraft before fueling, de-fueling or work on oxygen system.Approved fire extinguisher should be located at easily accessible area.


Working on A/cAircraft should be correctly choked, and appropriate covers and locks should be used when required.Before moving flight control surfaces ensure that movement is not obstructed by ground equipment, and dont posses hazard to personnel.Specified procedure and must be followed during removal or installation of aircrafts component.Dont use tools carelessly as this may scratch the aircraft paint finish and will introduce corrosion.


Working on A/cEnsure that aircraft electrical bonding wires and static discharges are left intact and connected after work has been completed.Always take extra care while handling the aircraft fluids. As there spillage may damage other aircraft parts.Approach the helicopter in view of the pilot. Never approach a helicopter carrying anything with a vertical height that the blades could hit. This could cause blade damage and injury to the person.Maitenance Practice-1

Shop SafetyThe highest standards of orderly work arrangements and cleanliness should be observed during the maintenance of aircraft.Where continuous work shifts are established, the outgoing shift should remove and properly store personal tools, rollaway boxes, all work stands, maintenance stands, hoses, electrical cords, hoists, crates, and boxes that were needed for the work to be accomplished.


Shop SafetySigns should be posted to indicate dangerous equipment or hazardous conditions. There should also be signs that provide the location of first aid and fire equipment.Safety lanes, pedestrian walkways, and fire lanes should be painted around the perimeter inside the hangars. This is a safety measure to prevent accidents and to keep pedestrian traffic out of work areas.Maitenance Practice-1

Shop Safety

Technicians and supervisors should watch for their own safety and for the safety of others working around them.

If other personnel are conducting their actions in an unsafe manner, communicate with them, reminding them of their safety and that of others around them.Maitenance Practice-1

Electrical SafetyIt is known that when electricity is applied to the human body, it can create severe burns.In addition, the nervous system is affected and can be damaged or destroyed.To safely deal with electricity, the technician must have a working knowledge of the principles of electricity, and a healthy respect for its capability to do both work and damage.Maitenance Practice-1

Electrical SafetyWearing or use of proper safety equipment can provide a psychological assurance at the same time it physically protects the user.The use of rubber gloves, safety glasses, rubber or grounded safety mats, and other safety equipment contributes to the safety of the technician working on or with electrical equipment.Two factors that affect safety when dealing with electricity are fear and overconfidence. While both a certain amount of respect for electrical equipment is healthy and a certain level of confidence is necessary, extremes of either can be deadly.


Electrical SafetyLack of respect is often due to lack of knowledge. Personnel who attempt to work with electrical equipment and have no knowledge of the principles of electricity lack the skills to deal with electrical equipment safely.Overconfidence leads to risk taking. The technician who does not respect the capabilities of electricity will, sooner or later, become a victim of electricitys awesome power.Maitenance Practice-1

Fire SafetyAnytime current flows, whether during generation or transmission, a byproduct of that flow is heat. The greater the current flow, the greater the amount of heat created.When this heat becomes too great, protective coatings on wiring and other electrical devices can melt, causing shorting, which leads to more current flow and greater heat. This heat can become so great so that metals can melt, liquids vaporize, and flammable substances ignite.Maitenance Practice-1

Fire SafetyTo prevent electrical fires :keep the area around electrical work or electrical equipment clean, uncluttered, and free of all unnecessary flammable substances.Never place wires or cords where they will be walked on or run over by other equipmentMaitenance Practice-1

Compressed GasStorage room for Gas cylinder should be well ventilatedCylinders should not be exposed to sunlight.Gas cylinders should not be laid on damp ground.Lightning for stores containing combustible gas cylinder should be flameproof.Breathing oxygen and welding oxygen should be segregated and properly labeled to avoid confusion.Grit, dirt and oil should be prevented from entering the cylinder valves.Acetylene cylinder should be stored vertically.


Compressed GasCompressed air, like electricity, is an excellent tool as long as it is under control.Inspect air hoses frequently for breaks and worn spots. Unsafe hoses should be replaced immediately.Keep all connections in a no-leak condition.Air used for paint spraying should be filtered to remove oil and water.Never use compressed air to clean hands or clothing. Pressure can force debris into the flesh leading to infection.Maitenance Practice-1

Compressed GasAir hoses should be straightened, coiled, and properly stored when not in use.Many accidents involving compressed gases occur during aircraft tire mounting. To prevent possible personal injury use appropriate lifting and mounting devices in mounting or removing heavy aircraft tires.


Welding SafetyWelding should be performed only in designated areas.Any part to be welded should be removed from the aircraft, if possible.A welding shop should be equipped with proper tables, ventilation, tool storage, and fire prevention and extinguishing equipment.Welding on an aircraft should be performed outside, ifpossible.Maitenance Practice-1

Welding SafetyIf welding in the hangar is necessary, observe these precautions:During welding operations, there should be no open fuel tanks, and no work on fuel systems should be in progress.No painting should be in progress.No aircraft are to be within 35 feet of the welding operation.No flammable material should be in the area around the welding operation.


Welding SafetyOnly qualified welders should be permitted to do the work.Fire extinguishing equipment of a minimum rating of 20B should be in the immediate area with 80B rated equipment as a backup.Aircraft being welded should be in towable condition, with a tug attached, and the aircraft parking brakes released. A qualified operator should be on the tug, and mechanics available to assist in the towing operation should it become necessary to tow the aircraft. If the aircraft is in the hangar, the hangar doors should be opened.Maitenance Practice-1

Fire ProtectionRapid oxidation, accompanied by a noticeable release of heat and light, is called combustion or burning.Requirements for Fire To Occur:Fuel: something that will, in the presence of heat, combine with oxygen, thereby releasing more heat and as a result reduces itself to other chemical compounds;Heat: accelerates the combining of oxygen with fuel, in turn releasing more heatOxygen: the element which combines chemically with another substance through the process of oxidation.


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Fire ProtectionClassification of Fires:For commercial purposes, the National Fire Protection Association (NFPA) has classified fires into three basic types: Class A, Class B, and Class C.Class A fires occur in ordinary combustible materials, such as wood, cloth, paper, upholstery materials, and so forth.Class B fires occur in flammable petroleum products of other flammable or combustible liquids, greases, solvents, paints, and so forth.Maitenance Practice-1

Fire ProtectionClass C fires occur involve energized electrical wiring and equipment.Class D fire Class D fires are not commercially considered by the National Fire Protection Association to be a basic type or category of fire since they are caused by a Class A, B, or C fire. Usually Class D fires involve magnesium in the shop or in aircraft wheels and brakes, or are the result of improper or poorly conducted welding operations.


Fire ExtinguishersAny type of fire can occur during maintenance on or around, or operations involving, aircraft. There is a particular type extinguisher which is most effective for each type of fire.Water extinguishers are the best type to use on Class A fires. Water has two effects on fire: it deprives fire of oxygen and cools the material being burned.Never use water-type fire extinguishers on Class D fires. Because metals burn at extremely high temperatures, the cooling effect of water causes an explosive expansion of the metal.


Fire ExtinguishersCarbon dioxide (CO2) extinguishers are used for Class A, B, and C fires, extinguishing the fire by depriving it of oxygen.Additionally, like water-type extinguishers, CO2 cools the burning material.Carbon dioxide (CO2) extinguishers are used for Class A, B, and C fires, extinguishing the fire by depriving it of oxygen. Additionally, like water-type extinguishers, CO2 cools the burning material.


Fire ExtinguishersNever use CO2 on Class D fires. As with water extinguishers the cooling effect of CO2 on the hot metal can cause explosive expansion of the metal.When using CO2 fire extinguishers, all parts of the extinguisher can become extremely cold, and remain so for a short time after operation. Wear protective equipment or take other precautions to prevent cold injury (such as frostbite) from occurring.Extreme caution must be used when operating CO2 fire extinguishers in closed or confined areas.Maitenance Practice-1

Fire ExtinguishersHalogenated hydrocarbon extinguishers are most effective on Class B and C fires. They can be used on Class A and D fires but they are less effective. Halogenated hydrocarbon, (commonly called Freon by the industry) are numbered according to chemical formulas with Halon numbers.


Fire ExtinguishersBromochlorodifluoromethane (Halon 1211), chemical formula CBrClF2, is a liquefied gas with a UL toxicity rating of 5. It is colorless, noncorrosive and evaporates rapidly leaving no residue. It does not freeze or cause cold burns, and will not harm fabrics, metals, or other materials it contacts. acts rapidly on fires by producing a heavy blanketing mist that eliminates oxygen from the fire source.It has outstanding properties in preventing reflash after the fire has been extinguished.Maitenance Practice-1

Fire ExtinguishersBromotrifluoromethane (Halon 1301): chemical formula CF3Br, is a liquefied gas with a UL toxicity rating of 6. It has all the characteristics of Halon 1211. The significant difference between the two is: Halon 1211 forms a spray similar to CO2, while Halon 1301 has a vapor spray that is more difficult to direct.


Fire ExtinguishersDry powderStored as a fine powder in a blue colored extinguisher, pressurized by a CO2 or a nitrogen cartridge.Suitable for brake fires and class B, C and D fires.Has a little cooling effect and fires may re-ignited.


Fire ExtinguishersDry powder extinguishers: while effective on Class B and C fires, are the best for use on Class D fires. Dry powder is not recommended for aircraft use (except on metal fires as a fire extinguisher) because the leftover chemical residues and dust often make cleanup difficult, and can damage electronic or other delicate equipment.


Fire ExtinguishersFoam: Two types of foamFluoroprotein (used on class B fires)Aqueous film (used on class A & B fires)

Not suitable for class C and D fires.Stored in white or cream colored extinguishers pressurized with CO2Maitenance Practice-1

Inspection of Fire ExtinguishersFire extinguishers should be checked periodically utilizing a checklist. If a checklist is unavailable, check the following as a minimum: Proper location of appropriate extinguisher Safety seals unbroken All external dirt and rust removed Gauge or indicator in operable range Proper weight No nozzle obstruction No obvious damageMaitenance Practice-1

Identifying Fire ExtinguishersFire extinguishers should be marked to indicate suitability for a particular class of fire.The markings should be placed on the fire extinguisher and in a conspicuous place in the vicinity of the fire extinguisher.When the location is marked, however, extreme care must be taken to ensure that the fire extinguisher kept at that location is in fact the type depicted by the marking. In other words, if a location is marked for a Class B fire extinguisher, ensure that the fire extinguisher in that location is in fact suitable for Class B fires.


Identifying Fire ExtinguishersMaitenance Practice-1


Identifying Fire ExtinguishersMarkings should be large enough and in a form that is easily seen and identifiable by the average person with average eyesight at a distance of at least 3 feet.Where markings are applied to wall panels, and so forth, in the vicinity of extinguishers, they should be large enough and in a form that is easily seen and identifiable by the average person with average eyesight, at a distance of at least 25 feet.Maitenance Practice-1


Using Fire ExtinguishersWhen using a fire extinguisher, make sure you have the correct type for the fire. Most extinguishers have a pin to pull that will allow the handle to activate the agent. Stand back 8 feet and aim at the base of the fire or flames. Squeeze the lever and sweep side to side until the fire is extinguished.Maitenance Practice-1

Oils Specified for components on the basis of their properties in relation to operating conditions of the component.High viscosity oil- for heavily loaded component at high temperature.Low viscosity oil- for lightly loaded application at low temperature.


OilsTurbine engine oilsAre low viscous, synthetic ester base formed from cocktail of chemical compounds.Type 1- first generation in older type enginesType 2 withstand the high temperature of later engines.Not compatible with each other.


OilsEster based fluid hygroscopic nature. Care in dispensing oil and with container.Aggressive to most of the paints finishes.Polyurethane provides best protection with them.


OilsNever mix type-1 and type-2.Wear protective gloves, apron and face shield when handling.Wash hands before smoke, eat or drink.Use correct dispensing equipment.Follow the correct replenishment procedure.


ChemicalsFlammable Chemicals: Spark, heat or a naked flame may ignite.At its flash point may ignite.Like fuels, oils, solvents and paints.

Prevent them with exposed to source of heat.Adequate ventilation to prevent the vapor concentration.Suitable containersAdequate fire extinguisherWear gloves and a respirator


ChemicalsCORROSIVE CHEMICALS:React with and attack metals and burn the skin.Etching agents, battery electrolyte and corrosion fluids.Mostly in liquid form but some be in powder form.

Adequate type of container.Avoid the contact with sensitive material.Clean the surface adequately.Wear suitable clothing, goggles or a face shield, gloves and apron.Take the precaution for fire flammable or toxicity. Check the eye wash facility.


ChemicalsToxic Chemicals:poisonous, can cause injuries or diseases in short term or long term. (asthma, cancers etc.)Have number of routes in the body- Breathe in the vapor, skin can absorb, carry substances onto food and into drink and ingest them. Solid chemical- harmful dust, hazardous fumes.Required personal protective equipment.


ChemicalsReactive Chemicals:Are those that experience a chemical change when exposed to other chemicals.Reaction may have slow change or voilent explosion.Some create high temperature causes to fire.Surface treatment- Alchrom, Cd-plating involve reactive chemicals.Some create toxic vapors- phosgene, chlorine and ferro-cyanide.


Safety Around Hazardous MaterialsAMaterial Safety Data Sheet(MSDS) is a document that contains information on the potential hazards (health, fire, reactivity and environmental) and how to work safely with the chemical product. It is an essential starting point for the development of a complete health and safety program.

MSDSs are prepared by the supplier or manufacturer of the material. It is intended to tell what the hazards of the product are, how to use the product safely, what to expect if the recommendations are not followed, what to do if accidents occur, how to recognize symptoms of overexposure, and what to do if such incidents occur.


Safety Around Hazardous MaterialsMSDS formats can vary from source to source within a country depending on national requirements.

It is intended to provide workers and emergency personnel with procedures for handling or working with that substance in a safe manner, and includes information such as physical data (melting point,boiling point,flash point, etc.),toxicity,health effects,first aid,reactivity storage, disposal, protective equipment, and spill-handling procedures.Maitenance Practice-1

Safety Around Hazardous MaterialsThe most observable portion of the Material Safety Data Sheet (MSDS) label is the risk diamond.It is a four color segmented diamond that represents Flammability (Red), Reactivity (Yellow), Health (Blue), and special Hazard (White). In the Flammability, Reactivity, and Health blocks, there should be a number from 0 to 4. Zero represents little or no hazard to the user; 4 means that the material is very hazardous. Maitenance Practice-1

Safety Around Hazardous MaterialsThe special hazard segment contains a word or abbreviation to represent the special hazard. Some examples are: RAD for radiation, ALK for alkali materials, Acid for acidic materials, and CARC for carcinogenic materials. The letter W with a line through it stands for high reactivity to waterMaitenance Practice-1

Risk DiamondMaitenance Practice-1

FlammabilityReactivityHealthSpecial Hazard

Safety Signs and Signals


Safety Around Machine ToolsHazards in a shops operation increase when the operation of lathes, drill presses, grinders, and other types of machines are used. Each machine has its own set of safety practices.


Safety Around Machine ToolsDrill Press: can be used to bore and ream holes, to do facing, milling, and other similar types of operations.The following precautions can reduce the chance of injury: Wear eye protection. Securely clamp all work. Set the proper RPM for the material used. Do not allow the spindle to feed beyond its limit of travel while drilling. Stop the machine before adjusting work or attempting to remove jammed work. Clean the area when finished.Maitenance Practice-1

Drill Press


Safety Around Machine ToolsLathes: are used in turning work of a cylindrical nature. This work may be performed on the inside or outside of the cylinder. The work is secured in the chuck to provide the rotary motion, and the forming is done by contact with a securely mounted tool.


LathesMaitenance Practice-1

Safety Around Machine ToolsLathes : following precautions can reduce the chance of injury: Wear eye protection. Use sharp cutting tools. Allow the chuck to stop on its own. Do not attempt to stop the chuck by hand pressure. Examine tools and work for cracks or defects before starting the work. Do not set tools on the lathe. Tools may be caught by the work and thrown. Before measuring the work, allow it to stop in the lathe.


Safety Around Machine ToolsMilling machines: are used to shape or dress; cut gear teeth, slots, or key ways; and similar work. The following precautions can reduce the chance of injury: Wear eye protection. Clean the work bed prior to work. Secure the work to the bed to prevent movement during milling. Select the proper tools for the job. Do not change the feed speed while working.Maitenance Practice-1

Safety Around Machine ToolsMilling machinesMaitenance Practice-1

Safety Around Machine ToolsGrinders: are used to sharpen tools, dress metal, and perform other operations involving the removal of small amounts of metal.The following precautions can reduce the chance of injury: Wear eye protection even if the grinder has a shield. Inspect the grinding wheel for defects prior to use. Do not force grinding wheels onto the spindle. Do not stand in the arc of the grinding wheel while operating, in case the wheel explodes. Do not force grinding wheels onto the spindle. They fit snugly, but do not require force to install them.Maitenance Practice-1

Safety Around Machine ToolsGrinders: Maitenance Practice-1

Battery MaintenanceBattery is an integral part of the electrical system in aircraft.Two types of batteries are used: Pb-acid and Ni-Cd. Charging rooms are potential very dangerous area.Hydrogen is vented during every stage of Pb-acid battery charging.


Battery MaintenanceThere must be separate room for Pb-acid and alkaline battery charging, repair/maintenance and electrical supply and storage.All tools and equipment must be separate and marked for the purpose.All electrolyte and neutralizing agents containers must be clearly marked.Charging rooms well vented, explosion proof lighted and with air extraction system.


Battery MaintenanceAmbient temperature in the charging rooms must be maintained within limits. e.g. lead acid- below 27 C and Ni-Cd 21 C.Floor Level, dry, dust free, proof against acid or alkali e.g. concrete. Bench: Height should be 20 inch from floor, to enable inspection and reduce lifting effort. Should be made of latticed panels of waxed wood.Co2 type fire extinguisher should be strategically placed.


Battery MaintenanceBattery charging supply is normally D.C. but supplied from A.C. distribution system.

When disconnecting batteries, the cable should be removed from the battery first and then from the charging board.

Individual charging boards should be mounted adjacent to each charging point and be mounted adjacent to each charging point and be mounted directly above and to rear of the bench to minimize the need for long connecting cables.


Battery MaintenanceH2SO4 SPILLAGE- should be washed in solution of bicarbonate of soda and fresh water. Other neutralizing agent Ammonia powder or borax powder.

Alkaline Solution- washed in saturated solution of boric acid (crystal and powder) and fresh water.


