Drilling and finishing holes in aircraft components
Overview
This standard identifies the competences you need to drill and finish holes in aircraft components, in accordance with approved procedures. The activities carried out will include the use of drilling machines and portable drills, using a range of cutters, as applicable to the type of hole and finish required. This will involve marking out using templates, marking out instruments and the appropriate work holding arrangements. The drilling activities will include the production and finishing of a range of holes and checking that the finished holes are to the correct specification.
Your responsibilities will require you to comply with organisational policy and procedures for the drilling and hole finishing activities undertaken, and to report any problems with the activities, materials or equipment used that you cannot personally resolve, or are outside your permitted authority, to the relevant people. You will be expected to work either with a high level of supervision or as a member of a team, and you will take personal responsibility for your own actions and for the quality and accuracy of the work that you carry out. Where team working is involved, you must demonstrate a significant personal contribution during the team activities in order to satisfy the requirements of this standard, and you must demonstrate competence in all the areas required by the standard.
Your underpinning knowledge will be sufficient to provide a sound basis for your work and will provide an informed approach to producing and finishing holes in aircraft components. You will understand the drilling and hole finishing processes used, and their application, and will know about the tooling and ancillary equipment, materials and consumables, in adequate depth to provide a sound basis for carrying out the drilling and hole finishing activities, and for ensuring that the completed components are to the required specification.
You will understand the safety precautions required when working with drilling machines, and with their associated tools and equipment, especially those for isolating the machine during tool mounting and setting, and when handling cutting tools and equipment. You will be required to demonstrate safe working practices throughout and will understand the responsibilities you owe to yourself and others in the workplace.
Performance criteria
You must be able to:
P1 work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
P2 confirm that the drilling machine is set up and ready for use
P3 operate the drill safely and correctly in line with operational procedures
P4 produce drilled components to the required specification and within the specified dimensional accuracy
P5 carry out quality sampling checks at suitable intervals
P6 deal with problems within your control and report those that cannot be solved
P7 shut down the equipment to a safe condition on conclusion of the machining activities
Knowledge and Understanding
You need to know and understand:
K1 how to work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
K2 the importance of wearing the appropriate personal protective equipment (PPE), and of keeping the work area clean and tidy
K3 the hazards associated with carrying out drilling and hole finishing activities on aircraft components, and how they can be minimised
K4 the safety mechanisms on the equipment used, and the procedure for checking that they function correctly
K5 how to stop the equipment in both normal and emergency situations, and the procedure for restarting after the equipment has been stopped in an emergency
K6 how to obtain and interpret drawings, standards, quality control procedures and specifications used for the drilling and finishing of holes
K7 the importance of producing holes to the correct surface finish values, and the methods used to achieve this
K8 the methods, techniques and equipment used to mark out and position components, prior to drilling and finishing the holes
K9 the different types and applications of drilling equipment
K10 types and application of hole cutting and finishing tools
K11 how to handle and store drills and finishing tools, safely and correctly
K12 the effects of clamping the workpiece in a jig/workholding device, and how this can cause distortion in the finished components/structures
K13 the different types and application of cutting fluids/compounds
K14 the cutting characteristics of different materials, and how this affects the type of tool used, cutting speeds, lubrication and surface finish
K15 the principles and effects of cold working when finishing holes in aircraft components
K16 the methods used to prevent corrosion on completion of drilling and finishing operations
K17 the quality control procedures used, inspection checks to be carried out on finished holes, and the equipment to be used
K18 the action to be taken in the event that holes fail to meet specification
K19 the issues that can occur with the drilling and finishing activities, and how these can be overcome
K20 the recording documentation to be completed for the activities undertaken and, where appropriate, the importance of marking and identifying specific pieces of work in relation to the documentation
K21 the extent of your own responsibility, and to whom you should report if you have problems that you cannot resolve
Scope/range
Scope Performance
- Carry out all of the following during the drilling and finishing activities:
- ensure that you have the correct documentation for the drilling/finishing activities (such as drawings, instructions, aircraft standards)
- adhere to procedures or systems in place for risk assessment, personal protective equipment and other relevant safety regulations and procedures to realise a safe system of work
- ensure that all tools and equipment used are within current calibration dates
- maintain safe access and working arrangements for the area in which the drilling/finishing will take place
- deal with defects in materials, components and equipment, in accordance with specified procedures
- dispose of waste items in a safe and environmentally acceptable manner, in line with company procedures
- leave the work area in a safe condition and free from foreign object debris
- return all tools and equipment to the correct location, on completion of the activities
- Use four of the following types of marking-out/setting equipment:
- rules/tapes
- squares
- vernier instruments
- slip gauges
- protractors
- electronic feeler gauge
- approved aero markers
- feeler gauges
- dividers/compass
- jigs for marking out
- scribers
- templates
- through skin sensor (TSS)
- laser tracking
- Use a range of workholding/guiding devices, to include three of the following:
- jigs/fixtures
- slave bolts
- gripping pins
- profile boards
- drill bars
- dowels
- jig pins
- drill blocks
- clamps
- ream blocks
- Produce and finish holes in aircraft components, using three of the following:
- bench/pedestal drill
- rackfeed drill
- pistol pneumatic drill
- angled pneumatic drill
- portable/rechargeable drill
- pecker drill
- straight pneumatic drill
- positive feed drill
- `spacematic' drill
- radial arm drill
- cold working pack (split sleeve and split mandrel)
- automated drills (such as vertical/horizontal plane and special drills)
- robotic drill
- Produce holes in aircraft components, using two of the following types of drill bits:
- twist
- cobalt
- piloted core
- diamond coated
- core
- stepped
- Produce and finish holes in two of the following materials
- aluminium alloys
- composites
- titanium
- other specific ferrous, non-ferrous or non-metallic material
- Carry out all of the following during the production and finishing of the holes:
- mark out, position and secure the item to be drilled, in accordance with company procedures
- use the specified techniques and procedures to produce and finish the holes
- select and use the correct cutting feeds and speeds
- use appropriate and adequate lubrication/coolant
- check that positional accuracy complies to specifications
- ensure that machined features are free from tool marks, burrs and sharp edges
- apply surface protection/coatings to finished holes on completion of the drilling activity (where appropriate)
- Produce and finish (including de-burring) holes in aircraft components, to include four of the following types of holes:
- through
- spot faced
- blind
- tapered
- stepped
- bored
- reamed
- dimpled
- counterbored
- holes with formed edges (such as radii)
- threaded (insert)
- holes with clearance fit
- de-burring
- holes with interference fit
- countersunk
- Check that finished holes meet the required specification, using four of following:
- plug gauges
- depth gauges
- hole gauges
- de-burring/chamfer gauge
- vernier gauges
- dial test indicators
- countersink check bolts
- surface comparator plates
- down-size dummy check bolts
- company specific gauges
- Produce finished holes which comply with one of the following standards:
- Civil Aviation Authority (CAA)/European Aviation Safety Agency (EASA)
- Ministry of Defence (MoD)
- Military Aviation Authority (MAA)
- Aerospace Quality Management Standards (AS)
- Federal Aviation Authority (FAA)
- BS, ISO or BSEN standards and procedures
- customer standards and requirements
- organisational standards and procedures
- manufacturers standards and procedures
- Complete the relevant paperwork, to include one from the following, and pass it to the appropriate people:
- build records
- log cards
- job cards
- aircraft log
- other specific recording method