Mod 07 ESSAYS PT 1

Module 7 1.

There is water contamination in the fuel tank. How would you carry out a water fuel contamination test and what are the other tests you could carryout? Describe any follow-up actions if contamination is found and continues in the future.

Introduction Jet fuels can have unwanted water that it collects during airplane operation. This is because the air can be moist or wet and condensation can get into the fuel tanks. It is necessary to drain the fuel tanks sumps regularly to remove this unwanted water. Safety a. Safety Barriers in position b. MLG Down locks are in c. Warning notices in flight deck d. Spark proof lighting e. Ensure the use of personnel protective equipment (PPE) - Goggles and gloves – spark proof! f. Fire equipment is on standby g. Electrically ground the sump drain tool to the airplane structure h. And correct bonding of aircraft is required to reduce the risk of electrostatic charge build up i. No use of Portable Electronic Devices risk of Fire, Distraction, and Aircraft System Interference, may occur. Bonding connections should be made to designated points or to clean unpainted metal surfaces, and should connect the installation delivering the fuel, with the aircraft or installation receiving the fuel. All connections should be made before to the start of fuelling, and not broken until fuelling is complete and the filler caps have been replaced where applicable Cap 748 Visual Examination and Testing for Contamination 2.1 a) b) c) d)

Fuel should be considered unfit for use in aircraft if a visual examination shows any of the following: More than a trace of sediment; Globules of water; Cloudiness; A positive reaction to water-finding paste, paper, powder or a chemical detector.

Tools & equipment

Main tank sump drain tool Paste, Paper, Powder, or detector element Testing Sufficient time should be given after landing (45 minutes to one hour) to allow any water to settle and any frozen water droplets to thaw and move to the bottom of the tank. Use the main tank sump drain tool to extract fuel from the sump drain valve. And ensure that there are no leaks coming from the valve after the drain tool is removed. The fluid will move into two layers if there is fuel in the sample. If the sample stays in one layer it can be all fuel or all water. Visual testing alone is inadequate to determine whether it is pure fuel or pure water. The presence of free or suspended water is indicated by a distinct change in the color of paste, paper, powder, or detector element that is used to detect water in the sample. CAP 748 If a fuel sample proves to be unsatisfactory then the sampling procedure should be repeated. If a third sample is necessary and proves to be unsatisfactory, then action should be taken to identify the cause of contamination and no fuel should be dispensed to aircraft from the installation concerned. It would, in this case, be advisable to inform and seek advice from the fuel supplier concerned B737-3/4/500 Chapter 12-11-00 A) Drain fuel samples from each sump valve into a transparent container. It is easier to find the water in the fuel if you use food coloring that can make a solution with the water. Put one or two drops of the food coloring into the fuel sample. B)

To remove the maximum quantity of water from the fuel, you must permit sufficient time (approximately 45 minutes). This permits any frozen water droplets to thaw and the water to go to the bottom of the tank. If you drain the sump immediately after the landing, it is possible that some of the water is frozen. This water stays in the tank.

C) Drain the tank sumps sufficiently to make sure you remove water or other contamination from the system.

Remember to start with a section on safety, and the precautions you would take. Mention the applicable local (airport and company), National and International regulations concerning the storage, handling and disposal of fuel. Keep a theme of safety throughout your essay. Use the same terminology as used in CAP 748.

2.

Describe how tooling and equipment is controlled within a Part-145 maintenance organisation.

Introduction EC 2042/2003 part 145 says all tools and equipment are to be controlled and calibrated to an officially recognised standard. And all serviceable and unserviceable tools and equipment must be stored separately. Storing conditions are in accordance with manufactures instructions. The responsibility of this, in my company, lies with the tooling manager and the storekeepers. Tool tags Computerisation Stores Calibration EC 2042-2003 145.A.25 (d) (d) Secure storage facilities are provided for equipment, tools. Storage conditions ensure segregation of serviceable from unserviceable equipment and tools. The conditions of storage are in accordance with the manufacturer's instructions to prevent deterioration and damage of stored items. Access to storage facilities is restricted to authorised personnel. EC 2042-2003 145.A.40 (b) (b) The organisation shall ensure that all tools, equipment and particularly test equipment, as appropriate, are controlled and calibrated according to an officially recognised standard at a frequency to ensure serviceability and accuracy. Records of such calibrations and traceability to the standard used shall be kept by the organisation. SRT Tool Procedure RESPONSIBILITY Tooling manager Storekeepers 3

PROCEDURE

3.1

Issues and Returns 3.1.1

A record is to be maintained of all tools issued from the Tools Store using the Company Computer system.

3.1.2

The Storekeeper will register issues per individual item of tooling against each trades person.

3.2

3.1.3

Tools will only be loaned when the tradesperson provides their Security pass.

3.1.4

On return of the tool the Storekeeper will re-position the item to its permanent location in the Tool Store. The record on the company computer system will be updated to show the return of the tool.

3.1.5

When the company system is unavailable, the tools will be issued via labels to maintain control. The tradesperson will sign the label and this is positioned into the permanent location of the tool. Line stations have tool tags assigned to each person and this is used to identify who has the tool signed out.

Controls 3.2.1

When an Aircraft is due to depart, a check of all outstanding tooling against an Aircraft registration must be carried out

3.2.2

All equipment and tools are to be visually checked for serviceability and completeness prior to use. Multi-part kits of tools are to be checked to ensure that all parts of the kit are serviceable and present immediately on issue and prior to return to stores.

3.2.3

On issue and return Tool Store Personnel must check all grease guns and sealant guns to ensure that they contain no grease cartridges, grease or sealant. If found, this must be disposed of, by the engineer.

3.2.4

A list of tools missing or damaged is to be forwarded to the Tooling Manager, who is to take appropriate recovery action.

3.2.5

Precision measuring equipment is subject to periodic inspection and calibration

3.2.6

To identify the period, during which the instrument or tool may be used before re-calibration is required, the Storekeeper must ensure that a calibration label has been attached to the item, stating the date when the re-calibration is due. Also, items which require proof loading will be checked to ensure a current inspection due date attached.

3.2.7

No tool / instrument may be issued or used if found inadvertently to be Unserviceable or date expired. A red unserviceable label is to be affixed to the item, which should then be processed for repair / re-calibration or test.

3.2.8

If a calibrated tool is found to have a missing or illegible calibration due label, the storekeeper will check the locally held records for the due date and a new label is attached.

3.2.9

The Storekeeper will ensure that conditions of storage within the tool stores are maintained commensurate with the tooling held.

3.2.10

At any time, if it becomes apparent to any member of the Tool Store that an item is not permanently marked, they must ensure that corrective action is taken as soon, as is practically possible.

3.2.11

Entry into the Tool Stores is controlled (Restricted Entry to Stores Area).

Notes: 1. 2. 3. 4.

Computer system to control stores Signed slip when computer is down Restricted entry to tool stores Engineers are responsible for clean tools

There are two aspects to the question - the company owned tools, or your own personal tools which you are personally responsible for. Decide which of the above tool types you are going to describe, but make it clear which you are writing about. You should end up with a couple of dozen link-words. Then consolidate them by grouping them under common headings, which ones are concerning stores procedures, which ones are which ones are concerning your own personal husbandry of tools etc. End up with a statement of whose ultimate responsibility it is that tools are clean, serviceable and calibrated, and retrieved from the aircraft at the end of the day/shift, or aircraft check.

3.

On a major hangar inspection corrosion is found on a Panel in an un-pressurised area of the fuselage. Detail your actions to return the aircraft to service.

Introduction CAIPs 6-10 and SRM The main principle of all repairs is that the repair shall at least restore the airframe to its original strength and shape. Safety Ensure aircraft is in a safe condition to work on. 1. Gear pins in 2. Flight controls in selected position 3. Landing gear door locked if in gear location 4. Access 5. Lighting – Spark proof lighting 6. Flight deck placards 7. Power tools dust – PBE and components covered 8. Cordons and barriers 9. Safety harness if required Type and location of Corrosion Location: Primary, Secondary And Tertiary Type: Surface to intergranular Type of material: (Aluminium Alloy, Magnesium, steel etc.) Extent of corrosion (superficial to severe) Repair Corrosion can be intergranular; therefore, the removal of the surface products of corrosion followed by reprotection is not necessarily effective. Re-protection Will depend on the material it is being applied to. Depending on the location and extent of corrosion damage, Repair or replacement of the component may be required. All repairs necessitated by corrosive attack, of whatever nature, must be made to an approved repair scheme in accordance with the manufacturer’s recommendations (SRM). Classification of repair 1. Negligible 2. Repairable (by patching) 3. Repairable (by insertion) 4. Repairable (by replacement)

Conclusion stuff CAP 562 Leaflet 6-10 Manufacturers’ maintenance documentation is being updated to include corrosion control and prevention, programs that give details of the areas most likely to suffer corrosion and the required maintenance actions. Poorly drained areas, the faying surfaces of joints, fuselage bilges, and structures concealed by soundproofing or hidden below freight bay floors, are typical of the areas liable to corrosive attack requiring particular attention. Operators and maintenance engineers are reminded of the continual need for vigilance to detect the onset of corrosion, particularly where ageing aircraft are concerned. Confirmed evidence of significant corrosion should be reported at once to the manufacturer and to the CAA.

If a repair was carried out, how would you inspect to ensure it is within limits, and what would you refer to for limits of damage? SRM, MEL What are the types of re-protection, and on what criterion does the choice depend upon? Type of Metal Paint, Primer, or leave unprotected What is done after completion of the work, to make the area clear, and what paperwork needs to be raised and who signs it? Clean up area, Certify, Licensed person Throughout your answer, notice how there is very little on the specific procedures involved. Your answer should continually state the options and possibilities, from corrosion types, location, extent, removal or repair options and methods, re-protection options and methods, with of course, a continual theme of safety throughout.

4.

There is 2 inches of wet snow on the aircraft and light snow is still falling, the temperature is 2°C, what are your considerations before releasing the aircraft for departure?

Introduction Snow and ice on aircraft in flight reduce lift, increase drag, and increase weight. All external surfaces must be free of snow, ice, and frost before an aircraft can take off. The Association of European Airlines (AEA) has recommendations for De-Icing / Anti-Icing of aircraft on the ground. Safety 1. De-icing / Anti-icing should be carried out by trained and qualified people. 2. Plugs to be kept on as long as possible 3. Install MLG down locks 4. Chocks in front and back of wheels 5. Ground the aircraft 6. Make sure the flaps, slats, spoilers, speed brakes and thrust reversers are retracted 7. Bleed air systems from APU and engine are stopped 8. Make sure all doors and sliding windows are closed 9. Use soft bristle broom to remove snow CAUTION:

DO NOT POINT A SOLID FLOW OF FLUID DIRECTLY AT THE SURFACE. APPLY THE FLUID AT LOW ANGLE TO PREVENT DAMAGE TO THE AIRPLANE SURFACES. DO NOT USE A HIGH PRESSURE SPRAY TO BLOW THE ICE AND SNOW OFF THE AIRPLANE SURFACES.

737-3/4/500 AMM Chapter 12-33-01 C. Definitions (1) Deicing is a procedure to remove the frost, ice or snow from the airplane. Hot water or a hot mixture of water and deicing/anti-icing fluid is applied to do this. (2) Anti-icing is a procedure to make sure that ice, snow and/or frost does not collect and become attached to the airplane surfaces. Anti-icing fluid or a mixture of anti-icing fluid and water is applied to the airplane to do this. (3) One step ice removal/anti-icing applies a hot deicing/anti-icing fluid or mixture of fluid and water. Use the conditions that follow to make a decision on how hot to make the fluid or the fluid and water mixture: (a) The ambient temperature (b) The weather conditions

(5)

Holdover time is the approximate time anti-icing fluid will keep the frost, ice, or snow off the airplane surfaces that have protection.

One step de-icing holdover time starts at start of operation and two step starts at end of the operation. CAUTION: The time of protection will be shortened in heavy weather conditions. Heavy precipitation rates or high moisture content, high wind velocity or jet blast may reduce holdover time below the lowest time stated in the range. Holdover time may also be reduced when the aircraft skin temperature is lower than OAT. De-icing/anti-icing fluids used during ground deicing/anti-icing are not intended for - and do not provide - protection during flight.

WARNING:

MAKE SURE YOU USE THE CORRECT EQUIPMENT FOR THE FLUID YOU USE. MECHANICAL OR EQUIPMENT SHEAR OF THE FLUID CAN OCCUR IF THE CORRECT EQUIPMENT IS NOT USED. IF THIS OCCURS, THE VISCOSITY OF MANY TYPE II FLUIDS WILL DECREASE AND, THUS, THE APPROXIMATE HOLDOVER TIME. MAKE SURE YOU REFER TO THE MANUFACTURER'S GUIDELINES FOR THE FLUID THAT YOU USE.

A general guideline is, Type II fluids give a longer holdover time than Type I fluids. Use Type II fluids to decrease the risk that ice, snow, or frost will collect on the airplane during a long taxi. Use fluids IAW manufacture recommendations. (l) Use soft bristle brooms with long handles to remove the snow from the wings and horizontal stabilizers. This will make it easier. You can use ropes or a fabric hose to remove the snow from the fuselage. Move the rope or hose back and forth on the top of the fuselage as you move it aft. When using mechanical means to remove snow, be careful not to damage aerials, vents, stall warning vanes, pitot tubes, and vortex generators. Hot air is not recommended as this will melt the snow or ice and the water will refreeze. Possibly in the flight control hinges or micro-switches of the control system. Use hot fluid spray

5)

Make sure that ice and/or snow is not pushed into the areas around the flight controls during ice and snow removal. 1. Use Fluids IAW Manufactures recommendations 2. Brush or Squeegee ‘Do not damage aerials, vents stall warnings vanes pitot tubes, vortex generators’ 3. Hot air not recommended, as this will melt the snow & refreeze the water 4. Use hot fluid spray

GUIDELINE SUMMARY FOR APPLICATION OF TYPE II FLUID MIXTURES (MINIMUM CONCENTRATIONS) AS A FUNCTION OF OAT MIXTURE SHOULD BE HEATED TO 80-90`C (176`-194`F) OAT

°C

CONCENTRATION (PERCENTAGE BY VOLUME) ANTI-ICING FLUID/WATER

°F

ONE STEP PROCEDURE

TWO STEP PROCEDURE DEICING 1ST STEP

-3

27

-7

19

50 / 50 INCLUDES ANTI-ICING IN REGARD TO WEATHER CONDITIONS

75 / 25 INCLUDES ANTI-ICING IN REGARD TO WEATHER CONDITIONS

WATER TREATED TO 80°C (180°F) MINIMUM AT THE TANK OR A HEATED MIX TYPE I OR TYPE II FLUID AND WATER 50/50 HEATED OR SUITABLE MIX OF TYPE I FLUID WITH FP NOT MORE THAN 3°C (5°F) ABOVE ACTUAL OAT

ANTI-ICING

2ND STEP ANTI-ICING*

50/50 TYPE II

75/25 TYPE II

75/25 HEATED OR SUITABLE MIX OF 100/00 TYPE I FLUID OR TYPE II WITH FP NOT MORE THAN 3°C(5°F) ABOVE ACTUAL OAT BELOW BELOW USE OF TYPE II FLUID FOR ANTI-ICING BELOW -25°C (-13°F) SHALL MAINTAIN 7° (13°F) BUFFER BETWEEN -25 -13 THE FP OF THE NEAT FLUID AND OAT,AND THE FLUID SHALL CONFORM TO THE LOWEST OPERATIONAL USE TEMPERATURE/AERODYNAMICE ACCEPTANCE LIMITATION. CONSIDER USE OF TYPE I FLUID WHERE TYPE II FLUID CANNOT BE USED.

CAP 562 Leaflet 10-1 Before Flight All external surfaces must be free of snow, frost or ice before an aircraft takes off and de-icing operations should be carried out as necessary (see CAP 512). Particular care is necessary when an aircraft has been removed from a heated hangar into falling snow since the snow will melt on the warm aircraft then re-freeze as it cools down, forming a thin layer of ice which may not be easily visible. Water systems should be filled with warm water and all covers should be kept in place until as near to departure time as possible Inspections A trained qualified person should do final check Control surface gaps & hinges Pressure sensing & radiator honeycombs checked for blockage All protrusions & vents for signs of damage Move flight controls by hand to check full movement or use control wheel gently, power operated control exert loads of force & may cause damage if circuits are frozen Certification A log book entry must be made as required by the CAA

This is a very specific question, since it specifies that the snow is heavy, and therefore manual removal, such as a brush, is the preferred method. Also, the sub-zero temperature implies that there is ice under the snow (or could be). These are already a start of your considerations. Notice that the question does not ask for the procedure to remove ice and snow, but merely your considerations [before, during and after the job]. If you know nothing about snow and ice removal, you could start by reading CAIPs AL/11-3 Its bang up-to-date and you'll notice a distinct development in technology, mainly the addition of the Types III and IV fluids, which CAN be used to remove snow.

You could start by talking about: Safety Equipment and materials Procedures to use Inspection Holdover Certification Not necessarily in that order, and be careful not to get bogged down in describing the procedures of snow and ice removal, when what you are asked for are your considerations whilst carrying out the procedures.

5.

Describe how you would replace a PCB and the precautions you would take.

Introduction ATA 20-41-01/201 Many electronic line replaceable units (referred to as LRUs) contain microcircuits and other sensitive devices, which can be damaged internally by electrostatic discharges. These LRUs are identified as Electrostatic Discharge Sensitive (referred to as ESDS). An electrostatic discharge is electrostatic energy transmitted between materials of different electrical potentials. Safety 1. Power off or system isolated i.e. C/B pulled and tagged and annotated in log book 2. Keep any contamination or unwanted material away from sensitive device. Malfunction can occur 3. use a wrist strap with minimum grounding resistance of 250 kilohms and max 1.5 megohm 4. PCB’s not fitted must be placed in a conductive bag or container with ESDS placard, bag sealed with 100% cotton twine 5. Electrostatic charges can be caused be these: Human hair, clothing, floors, equipment racks, and equipments units. 6. Damage to components can be caused by one electrostatic discharge. Removal NOTE: The placards on the outer area of the card files show the cards that contain the ESDS printed circuit boards that are LRU's. MAKE SURE YOU KEEP CONTAMINATION OR UNWANTED MATERIAL AWAY FROM THE SENSITIVE DEVICE. CONTAMINATION OR UNWANTED MATERIAL NEAR THE SENSITIVE DEVICE CAN CAUSE A MALFUNCTION IN THE SENSITIVE DEVICE. Remove the system electrical power with the applicable Removal/Installation procedure.

CAUTION:

(1)

WARNING:

USE A WRIST STRAP WITH A MINIMUM GROUNDING LEAD RESISTANCE OF 250 KILOHMS AND A MAXIMUM OF 1.5 MEGOHMS. USE OF A LOW RESISTANCE WRIST STRAP CAN CAUSE INJURY TO PERSONS IF A HIGH VOLTAGE SOURCE IS TOUCHED.

(2)

Do these steps to do a test of the wrist strap resistance: (a)

(b) (c)

(3)

Use an ohmmeter to make sure the wrist strap assembly has a minimum resistance of 250 kilohms and a maximum of 1.5 megohms. Put the wrist strap on your wrist. Use an ohmmeter to make sure the resistance is less than 10 megohm.

Connect the wrist strap into the ELECTROSTATIC GROUND JACK of the card file.

CAUTION:

THE GROUNDING LEAD ON THE WRIST STRAP MUST TOUCH THE SKIN TO GIVE THE PROTECTION THAT IS NECESSARY. FAILURE TO USE THE WRIST STRAP CORRECTLY CAN CAUSE DAMAGE TO THE ESDS PRINTED CIRCUIT BOARDS.

(4)

Attach the wrist strap correctly on the person that will remove the printed circuit board.

(6)

From the location decal, find the printed circuit board to be removed.

(7)

Use the top and bottom (or left and right) extractors on the printed circuit board to remove it from the card file.

(8)

Put the printed circuit board in the conductive bag or the container with the ESDS placard.

CAUTION:

DO NOT USE STAPLES OR ADHESIVE TAPES TO CLOSE THE CONDUCTIVE BAGS. FAILURE TO CLOSE THE CONDUCTIVE BAGS CORRECTLY CAN CAUSE DAMAGE TO THE PRINTED CIRCUIT BOARD.

(9)

Use an ESDS label or a 100% cotton twine to close the conductive bag. The printed circuit boards in a conductive bag NOTE: must be put in a rigid container to make sure the conductive bag stays in a satisfactory condition. (11) Remove the wrist strap. ESDS Printed Circuit Boards - Installation A. Equipment (1) (2) (4)

Conductive Bags Conductive Plastic Carrier Wrist Straps

NOTE:

(5) (6)

A wrist strap is kept on the plenum of the racks E1-E2 in the main equipment centre

100% Cotton Twine - Commercially Available ESDS Labels

Installation CAUTION: MAKE SURE YOU KEEP CONTAMINATION OR UNWANTED MATERIAL AWAY FROM THE SENSITIVE DEVICE. CONTAMINATION OR UNWANTED MATERIAL NEAR THE SENSITIVE DEVICE CAN CAUSE A MALFUNCTION IN THE SENSITIVE DEVICE. (1)

Remove the system electrical power with the applicable Removal/Installation procedure.

WARNING: USE A WRIST STRAP WITH A MINIMUM GROUNDING LEAD RESISTANCE OF 250 KILOHMS AND A MAXIMUM OF 1.5 MEGOHMS. USE OF A LOW RESISTANCE WRIST STRAP CAN CAUSE INJURY TO PERSONS IF A HIGH VOLTAGE SOURCE IS TOUCHED. (2)

Do these steps to do a test of the wrist strap resistance: (a) Use an ohmmeter to make sure the wrist strap assembly has a minimum resistance of 250 kilohms and a maximum of 1.5 megohms. (b) Put the wrist strap on your wrist. (c) Use an ohmmeter to make sure the resistance is less than 10 megohm. (3) Connect the wrist strap into the ELECTROSTATIC GROUND JACK of the card file. CAUTION:

(4) (5) (6) (7) (8)

THE GROUNDING LEAD ON THE WRIST STRAP MUST TOUCH THE SKIN TO GIVE THE PROTECTION THAT IS NECESSARY. FAILURE TO USE THE WRIST STRAP CORRECTLY CAN CAUSE DAMAGE TO THE ESDS PRINTED CIRCUIT BOARDS.

Attach the wrist strap correctly on the person that will remove the printed circuit board. Open the access door on the card file. From the location decal, find the printed circuit board to be installed. Remove the ESDS printed circuit board from the conductive bag or the carrier. With the top and bottom (or left and right) extractors, put the printed circuit board into the card file.

(9) Attach the printed circuit card with the extractors. (10) Close the access door for the card file. (11) Remove the wrist strap.

Remember to describe how you would make the aircraft, and especially the particular system, safe to work on before commencing the removal. As this is basically a component replacement question, include all the usual stuff regarding component replacement (acceptance of component / paperwork / inspection / bogus parts / quarantine of old card etc.) paying particular attention to the ESD specialist procedures. Wrist strap Grounding ESD bag Labels Bag sealing Storage box Connector blanks Tongs Remember to describe in your essay the closing up inspection, function/operational/BITE test, and of course, the paperwork and certification. Conclusion Function check Correct paperwork i.e. EASA form 1 or 8130-3 Logbook entry signed by approved licensed engineer

Describe how you would make a hole in metal, wood or a composite compound. Discuss this in context of aircraft maintenance. State the precautions to be taken and include any limits or tolerances that the usage of these tools can achieve. Introduction To drill a satisfactory hole in any material, the correct type of drill bit must be used. Before selecting the drill type and drilling parameters, the material type and lay-up should be known to allow the correct drill type to be selected. Safety Use of appropriate dust mask and goggles is required, depending type of materials being drilled. Electrical components should be protected from dust and debris during drilling. Use of dust proof vacuum attachments could be used. Suitable dust extraction is required not only for health and safety reasons but also to prevent conductive and abrasive carbon dust infiltrating any electrical circuits. Be aware of what’s behind the part being drilled. Ensure the object being drilled is secure and not going to move before drilling. Swarf Drilling into aluminium structure creates shavings, called swarf. If those bits of swarf fall onto wire, they can eventually cut or wear through insulation, giving rise to intermittent (or worse) electrical failures. To be sure, it takes time to put a cover over the wires while drilling, then folding up the covers and removing them from the airplane. But it may take less time than involved in finding swarf-related faults in the wiring weeks or months later, Aluminium swarf isn't good for wire-bundles and it's deadly once oxidized by an oxygen gas-flow. Ensure swarf from structural repairs is completely removed and does not become trapped in wiring looms. Metal shavings left in looms can eventually cut through insulation and cause short circuits Care must be taken with drilling to avoid the creation of additional damage around the hole, especially for laminated composites where damage can be introduced in the form of delaminating and cracking.

Speeds Speed depends on the size of drill and material being drilled; in general, the larger the drill, the slower the speed. Lubrication Lubrication prevents excessive heat, which preserves the temper of the drill. Type of lube depends on the material being drilled. And size of drill Wood Wood being softer than most metals, drilling in wood is considerably easier and faster than drilling in metal. Cutting fluids are not used or needed. The main issue in drilling wood is assuring clean entry and exit holes and preventing burning. Avoiding burning is a question of using sharp bits and the appropriate cutting speed. Drill bits can tear out chips of wood around the top and bottom of the hole and this is undesirable in fine woodworking applications Metal Under normal usage, swarf is carried up and away from the tip of the drill bit by the fluting of the drill bit. The continued production of chips from the cutting edges produces more chips, which continue the movement of the chips outwards from the hole. This continues until the chips pack too tightly, either because of deeper than normal holes or insufficient backing off (removing the drill slightly or totally from the hole while drilling). Lubricants and coolants (i.e. cutting fluid) are sometimes used to ease this problem and to prolong the tools life by cooling and lubricating the tip and chip flow. Coolant is introduced via holes through the drill shank (see gun drill). Boeing SRM 51-20-07 CAUTION: MACHINING OF COMPOSITE STRUCTURES PRODUCES DUST AND PARTICLES. BREATHING DUST OR ALLOWING DUST OR PARTICLES TO CONTACT EYES IS HAZARDOUS. WEAR APPROVED DUST MASK AND SAFETY GLASSES WHEN DRILLING, REAMING OR COUNTERSINKING COMPOSITE STRUCTURES. USE OF VACUUM PICKUP WHEN DRILLING IS RECOMMENDED. CAUTION:

PROTECT ELECTRIC MOTORS, SWITCHES, RELAYS, CONTACTS AND ELECTRONIC CIRCUITS FROM GRAPHITE DUST. USE DUST PROOF VACUUM ATTACHMENTS TO POWER TOOLS. GRAPHITE DUST IS ABRASIVE AND AN ELECTRICAL CONDUCTOR.

PERMANENT DAMAGE TO ELECTRICAL EQUIPMENT MAY OCCUR. 1.

The drill operation is best accomplished by placing the drill against the work before rotation, then applying a steady, medium force, and then operating the drill motor.

2.

See Figure 1/GENERAL, Table VIII for drill selection, speed, and feed and lubrication requirements.

3.

All holes should be piloted first, drilled and reamed to size. Refer to Figure 1/GENERAL, Table XIII for reaming speeds and type of reamers being used.

4.

For close tolerance holes 5/16 and over drill 1/32 undersize, and 5/16 and under drill 1/64 undersize. Then ream to size. CAUTION: MAINTAIN A CHIP CLEARANCE SPACE OF 3/16 TO 3/8 INCH BETWEEN THE DRILL JIG AND THE PART BEING DRILLED.

Try these websites for information. http://en.wikipedia.org/wiki/Drill_bits http://www.diydata.com/tool/drillbits/drillbits.php http://composite.about.com/library/weekly/aa991028.htm http://www.rapra.net/vircon/2_2_1.asp Preparation and tool selection for drilling are dependent upon the composite system. Drill material, drill geometry, drill rpm settings, feed control rates and the provision of a firm backup support while drilling all require attention. Drilling holes Types of drills for each material Specific methods of using drills (hand, machine, lathe etc.) Use and reasons for different drill angles, cutting speeds, lubricants, specialist methods (pilot drilling etc.) Safety precautions (clamping, dust, eye protection etc.) Safety and access Types of drill (windy) used on aircraft (and why).

Regulatory requirements (design/manufacturer authority, critical areas) Wood drills have fairly poor tolerances due to the nature of the material being drilled. Describe: Types of drills for each material Specific methods of using drills (hand, machine, lathe etc.) Use and reasons for different drill angles, cutting speeds, lubricants, specialist methods (pilot drilling etc.)

7.

Discuss the methods of protection against HIRF and the checks/inspections which would be carried out after a fault was entered in the tech log.

Introduction HIRF – High Intensity Radiated Fields is the electromagnetic environment that exists from the transmission of high power RF energy into free space. This could be external or internal of the aircraft. Modern aircraft transmit and receive RF signals in the atmosphere external to the aircraft. In addition, RF signals are conducted and radiated within the aircraft, through electrical cabling, to control and communicate with various electronic systems. High-intensity radiated fields (HIRF), produced by powerful radar transmitters or lightning, will partially penetrate a commercial aircraft through apertures in the aircraft's hull. Safety No fuelling going on Both the system causing fault and being affected by the fault must be safe to work on. Chocks in Flight control in selected position Protection - Cable shielding - adequate and undamaged - LRU access panels - closed and sealed properly - EMI filters - fitted and correct type - Full backshell connectors - fitted correctly and not damaged Inspections are to make sure that the designed protections are in good shape such as: A. Bonding wires are not corroded, damaged...not to gain resistance. B. Shielding are in good shape by checking their resistance with loop resistance test.... C. Fillet seals at connectors, plugs....are not deteriorated, which may cause moisture ingestion, corrosion, loss of shielding.... D. Static wicks are not broken, missing E. Structural and other repairs/mods are performed in a manner not to affect the existing.... Example of a fault MaxJet – during HF transmission Auto Pilot inputs being made. Cause was Co-axial cable shielding in poor condition on back of HF transceiver.

Include a function test where possible. Use the following framework: HIRF description: A few lines explaining what it is (be sure to spell out the acronym "High Intensity Radiated Field" correctly). The problems it can cause. Gather information. List the sources of information you will use to diagnose the problem. Make aircraft safe to work on. Describe the safety procedures to make you, your colleagues and the aircraft safe before commencing work. Component replacement - if necessary, Include all the usual stuff regarding component replacement (Acceptance of components / bogus parts / removal fitment / quarantine of old part etc. etc.) Inspection and Certification, The usual stuff. Include procedures for when "no fault found" (as is often the case with HIRF problems).

Watch out not to mix this inspection with lightening, the later is described their in your AMM ch 5. There is a whole chapter on it (and EMI) in The Avionics Handbook Chapter 25.3

Describe the inspection of a brake unit. What would be your actions if you find a brake unit worn to limits? Airbus ATA 32-41-08 / 601 Boeing ATA 32-41-41-6 Safety Main landing gear door locks in, chocks in, flight controls in selected position. MLG down lock gear pins installed. Persons and equipment clear of thrust reversers, flight control surfaces and landing gear when hydraulic power is switched on. Ensure brakes are not hot. Replacement part Part number – correct effectivity Serial number Inspection Look for leaks Position of wear indicator A.

Supply Electrical Power, WARNING:

B. C. D.

Install down lock pins Chock the tires Release the parking brake WARNING:

E. F.

MAKE SURE THE DOWNLOCK PINS ARE INSTALLED ON ALL THE LANDING GEAR.

KEEP PERSONS AND EQUIPMENT CLEAR OF THE FLIGHT CONTROL SURFACES, THE THRUST REVERSERS, AND THE LANDING GEAR. THESE COMPONENTS CAN MOVE SUDDENLY WHEN YOU SUPPLY HYDRAULIC POWER. THIS CAN CAUSE INJURIES TO PERSONS AND DAMAGE TO EQUIPMENT.

Supply Hydraulic pressure to the normal brake system. Procedure (1) Do these steps to examine the brakes for wear: (a) Fully push the captain’s left and right brake pedals and hold.

NOTE: You can set the parking brake to hold the brake pedals. (b) For each brake (4 locations), make sure the wear indicator pins extend out of the guides.

(c) Replace the brake if the end of a wear indicator pin is level with, or below the face of a guide. Conclusion Replacement brake must be correct part number and effectivity IAW IPC. Part must be from an approved source, which will be indicated on the 8130-3 or the EASA form 1

8.

There is no hydraulic pressure indicated on the left system. Detail your actions to make the aircraft serviceable.

Safety Chocks down lock pins Flight controls in selected position Persons and equipment clear of thrust reversers, flight control surfaces and landing gear when hydraulic power is switched on. HYDRAULIC FLUID CAN CAUSE INJURIES TO PERSONS. IF THE HYDRAULIC FLUID TOUCHES THE SKIN, FLUSH YOUR SKIN WITH WATER. IF THE HYDRAULIC FLUID TOUCHES YOUR EYES, FLUSH THE EYES WITH WATER AND GET MEDICAL AID. Checks A. Quantity low B. Is the pump running? Move Flight Controls to check. Make sure there is a safety man. C. Pressure transmitter D. Indicator E. Wiring F. CB tripped G. Is pump running

You probably have a detailed template for any "defect rectification" question. It probably includes key points under the headings something like: Safety Gathering info. Troubleshooting Possible causes Rectification Inspection and test Paperwork and certification Any follow-ups You notice that there is no hydraulic pressure indicated on the left system: You must be sitting in the pilot's seat already, aircraft powered up and hydraulics switched on - you must be on a systems test or a daily check or similar. Before you start getting your PPE out, pulling circuit breakers, placing placards and all that safety stuff - wouldn't you do some cross-indicator troubleshooting right from where you are?

Is it an indicator fault? Possible if a small aircraft with "steam gauges", unlikely if it is EICAS/ECAM and all other indications are working. Perhaps a sensor fault. Bring up the EICAS page, or ECAM synoptic page and check for hydraulic qty, temperature, which pumps are/are-not working? Just by doing this, you would be able to isolate the problem to one of indicator, sensor, leak or pump problem, all without moving from your seat, Look for possible "human error" - look above/behind you (wherever the CB is). Is the engine that drives the pump running? Is the other pump on? Select a different/standby pump - all the time watching the pressure indication. Only after that do you need to go downstairs and get the trouble-shooting manual, do a BITE interrogation (if exists on system). And only after you have narrowed down the possible cause, do you need to make certain systems/areas safe to work for visual inspection and possible component replacement. Rectification of defect is a standard template application of defer (describe requirements and implications of deferring a defect), or component replacement, (safety, acceptance of new parts/quarantining of old parts, IAW AMM etc. etc.) using lots of terms like "as required" and "if necessary" because you do not know what you are replacing. System inspection, function test, certification, paperwork and possible follow-ups are also standard.

10. Micrometers and Dial test indicators are used as precision equipment. Discuss the use of this equipment, their limitations and state the precautions to be taken when using them. Precautions Temperature of instrument and work piece should be the same Lay instruments on side when not in use When taking internal measurements with a micrometer you must add the width of the nibs Checks before use Check instrument is within calibration date Always check for correct zero setting. On 0” – 1” micrometers Screw spindle down on the anvil till the ratchet slips the reading should be 0”. For larger micrometers test pieces are provided. Accuracy Accuracy depends on the user, the temperature of the instrument/work piece, and the quality of the instrument. Some instruments have a temperature marked on them and this is the temperature at which they are most accurate. Usually 20°C Micrometer limitation is in thousandths and ten thousandths of an inch. There are various types of micrometers available. The accuracy of each instrument is as follows: English micrometer.0.001 inch English vernier micrometer.0.0001 inch Metric micrometer.0.01mm Metric vernier micrometer.0.001mm Dial test indicator accuracy is in thousandth of an inch. Vernier calliper Apart from inaccuracies caused by the permitted tolerances of manufacture, the accuracy is adversely affected by wear or dirt on the gauging faces, and unskilful handling. a) Before use, check that the instrument is in calibration (due every 6 months) the zero reading must be checked by cleaning the gauging faces and closing the jaws using firm finger pressure, and securing the frame with the locking screw. b) Hold the instrument to a source of light; dirt, wear or strain causing poor contact will be indicated by chinks of light between the faces.

c) Check the vernier scale locating screws for security, and check the zero reading. If zero marks not aligned-note the error. Adjustment can be made by loosening the vernier scale securing screws then re-positioning the vernier scale to read zero, then tightening the securing screws. And re-checking. d) Check a known dimension toward the limit of the instruments measuring capacity, this checks any distortion or ‘bowing’ of the beam. Limitations

LBP notes: On the Vernier Height Gauge. Precautions It is essential that the base of the instrument is at all times in contact with the surface table. It is advisable not to pre-set the instrument. Otherwise the scriber may override the work piece. The scriber should be lowered/raised slowly using the fine adjustment until the required feel is obtained. Since the main scale does not start at zero it is necessary to use an accurately ground distance piece, which is usually supplied with the instrument. Adjustment of the vernier scale is similar to that used for the vernier calliper. Dial Test Indicator In use it is rigidly supported, often by being fixed to a scribing block on a marking-off table, and is set to the first height with which comparison is desired. This is done by bringing the plunger over the first height then adjusting the zero on the D.T.I by turning the bezel until the zero is under the needle. If any other height is now compared by the sliding it under the plunger the needle will indicate on the + side if it is larger and on the – side if it is smaller: the difference in size will each case be read off directly on the dial. In use, the gap between the gauging faces should be adjusted by means of the fine adjustment before the frame locking screw is secured. The jaws make contact to give the feel of a smooth push fit. Two or three readings should be made at the same point to give accuracy.

In terms of micrometers and DTI, a brief statement describing what they are, why they are used, when they are used, where they are used and how they are used. CAIPs BL/3-5 provides a full description of the different types of micrometers, their accuracy, how to use them and how to care for them. "Limitations" means how accurate they are, and what materials and surfaces and component (shapes and sizes etc) they cannot be used on. "Precautions" means pre-use checks, errors due to mishandling, storage conditions, calibration requirements etc. all of which are described in the above two sources of information. With a bit of thought you should be able to put a page of factual information together. Micrometer and dial test indicator limitation. Technically, you should call them "resolutions", since accuracy is something else.