Maintaining power plant on aircraft
Overview
This standard identifies the competences you need to carry out maintenance activities on aircraft power plant, in accordance with the approved aircraft maintenance manual, approved change documentation (service bulletin) and airworthiness requirements. It covers both fixed wing and rotary winged aircraft, and covers the overall power package/engine dressing, inclusive of engine air intakes, engine mounts, cowling, scoops and cowl flaps. It does not cover engine strip down and maintenance activities, which are covered in other standards/ATA chapters. The maintenance activities will include carrying out a complete engine change, and the removal, fitting and testing of a range of power plant components. You will remove the required components and fit approved replacements, as appropriate. You will then need to test and adjust the completed system to meet the aircraft maintenance manual, change documentation (service bulletin) and airworthiness requirements.
Your responsibilities will require you to comply with the specific practices and procedures identified in the aircraft manual, change/service bulletin documentation and airworthiness requirements for the maintenance activities undertaken, and to report any problems with these requirements that you cannot personally resolve, or that are outside your permitted authority, to the relevant people. You must ensure that all tools, equipment and materials used are correctly accounted for on completion of the activities, and that all necessary job/task documentation is completed thoroughly, accurately and legibly. You will be expected to work with a minimum of supervision, taking personal responsibility for your own actions and for the quality and accuracy of the work that you carry out.
Your underpinning knowledge will provide a good understanding of your work, and will provide an informed approach to applying the appropriate maintenance techniques and procedures to aircraft power plant. You will understand the component removal, fitting and testing methods and procedures, and their application, along with the power plant maintenance requirements. You will know how the equipment functions, the common problems that can occur, the purpose of the individual components and associated defects, in adequate depth to provide a sound basis for carrying out the maintenance activities, correcting faults and for ensuring that the aircraft power plant is maintained to the required standard.
You will understand the safety precautions required when working on the aircraft power plant, especially those for ensuring that the power plant, and its fuel supply, is safely and correctly isolated. You will be required to demonstrate safe working practices throughout, and will understand your responsibility for taking the necessary safeguards to protect yourself and others in the workplace.
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Notes:
- This standard is designed to cover the practical experience requirements of the Airline Transport Association (ATA) Chapter 71 Aircraft Power Plant.
- To display competence in this standard, it is necessary to both remove and fit aircraft power plant components. You must remove components; however, you may fit a replacement component where the original was previously removed by another person. You should also be aware of how to leave a system in a safe condition if maintenance tasks cannot be completed. This covers both the physical systems and the job documentation.
Performance criteria
You must be able to:
- work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
- follow the relevant maintenance schedules to carry out the required work
- carry out the maintenance activities within the limits of your personal authority
- carry out the maintenance activities, and replace components in the specified sequence and in an agreed timescale
- report any instances where the maintenance activities cannot be fully met or where there are identified defects outside the planned schedule
- complete relevant documentation in accordance with organisational requirements
- dispose of waste materials in accordance with safe working practices and approved procedures
- leave the aircraft and power plant in a safe and appropriate condition, free from foreign object debris on completion of the activities
Knowledge and Understanding
You need to know and understand:
- the specific safety practices and procedures that you need to observe when working on aircraft power plant (including any specific legislation, regulations/codes of practice for the activities, equipment or materials)
- the need to check that cabin/cockpit switches, selectors and circuit breakers are in the correct position before applying any form of external power (such as electrical, hydraulic, air or vacuum)
- the importance of maintenance on aircraft power plant, and impact upon Extended Range Twin-Engine Operations Procedures (ETOPS) systems, Electrical Wiring Interconnect Systems (EWIS), legislation and local procedures
- the requirements and importance of understanding and applying human factors as defined by the regulatory requirements and the potential impact if these are not adhered to
- the hazards associated with carrying out maintenance activities on aircraft power plant, and with the tools and equipment used (such as handling oils, greases, aviation fuel, the safe release of fuel and other fluids, traps from moving parts, hot parts of engines, misuse of tools), and how to minimise them and reduce any risk
the protective equipment that you need to use for both personal protection (PPE) and protection of the aircraft
what constitutes a hazardous voltage and how to recognise victims of electric shock
how to reduce the risks of a phase to earth shock (such as insulated tools, rubber matting and isolating transformers)
the importance of aircraft husbandry and of ensuring that, throughout the maintenance activity, the aircraft and work area are maintained free from foreign objects, and the implications of FOD to the safety of the aircraft
- how to extract and use information from aircraft manuals, log books, flight logs, charts, system and physical layouts, specifications, symbols used in aircraft power plant, and other documents in the maintenance activities
- how to carry out currency/issue checks on the specifications you are working with
- terminology used in aircraft power plant, and the use of system diagrams and associated symbols
- the principles of operation of the power plant being worked on, and the function of the units that make up the system
the techniques used to remove power plant and power plant components without damage to the components or surrounding structure (such as release of pressures/force, draining of fuel/fluids, removal of components and the need to protect the system integrity by ensuring that exposed components and pipe ends are correctly covered/protected)
the various mechanical fasteners to be removed and replaced, and their methods of removal and replacement (such as threaded fasteners, special securing devices)
- the various types of electrical connector that are used, methods of unlocking, orientation indicators and locating and locking-in of the connections
- why electrical bonding is critical, and why it must be both mechanically and electrically secure
- the need to label and store correctly components that require repair or overhaul, and to check that replacement components have the correct part/identification markings and accompanying release documentation
- how to remove and refit aircraft power plant components safely and correctly (such as use of lifting and handling equipment; ensuring the correct tightness of connections; eliminating stress on pipework/connections; carrying out visual checks of all components)
- how to make adjustments to components/assemblies to ensure that they function correctly (such as travel and working clearance)
- why securing devices need to be tightened to the correct torque, locked and labelled, and the different methods that are used
- the tools and equipment used in the maintenance activities, and their calibration/care and control procedures
- why tool/equipment control is critical and what to do if a tool or piece of equipment is unaccounted for on completion of the activities
- the routine checks and tests to be carried out on the aircraft power plant
- how to conduct engine ground runs and the engine data/parameters to be recorded
- the importance of carrying out the engine ground run in accordance with the aircraft manual and regulations
- how to record the results of the engine ground run and the documentation that must be used
- how to analyse the ground run results and how to make valid decisions about the acceptability of the aircraft power unit under test
- the procedures to be followed if the power plant fails to meet the ground run specification
- the procedure for the safe disposal of waste materials, scrap components and fuel/fluids
- the extent of your own authority 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 maintenance of the aircraft power plant system:
- ensure that appropriate authorisation to work on the aircraft is obtained, and observe all relevant isolation and safety procedures
- obtain and use the correct documentation (such as job instructions, technical instructions, aircraft manuals and maintenance documentation)
- obtain the correct tools and equipment for the activity, and check that they are in a safe. tested and usable condition and within current calibration dates
- adhere to procedures or systems in place for risk assessment, COSHH, personal protective equipment and other relevant safety regulations and procedures to realise a safe system of work
- ensure the safe isolation and draining of fuel and oil pipes/lines before breaking into the system
- ensure that the relevant safety devices and mechanical/physical locks are in place (where appropriate)
- use approved removal, fitting and testing techniques and procedures at all times
- return tools and equipment to the correct storage location on completion of the activities
- ensure that work carried out is correctly documented and recorded
- ensure that any outstanding tests are correctly documented
Carry out both of the following activities:
- contribute significantly to an engine removal
- contribute significantly to an engine installation
Plus: Carry out maintenance on three of the following parts of the aircraft power plant:
3. cowling/containment
4. fireseals and shrouds
5. engine air intakes
6. engine mounts
7. electrical harness
8. engine drains
9. attached fittings
10. nozzles and jet pipes
11. reverse thrust
12. exhaust components
- Remove and fit four different aircraft power plant components (at least two must be from group A):
Group A
1. accessory section cowls
2. scoops
3. flame arrestors vents
4. nose ring cowls
5. actuators
6. fire wire
7. compressor fan cowls
8. engine mounts
9. fire detection units
10. buried engine ducts
11. vibration dampers
12. fire bottle
13. vortex generators
14. drain lines
15. electrical plugs/sockets
16. cowl flaps
17. manifolds
18. conduits
19. cowling supports
20. tanks
21. position indicators
22. hydraulic pump
23. integrated drive generator (IDG)
24. starter
25. nozzle exhaust
26. fuel control/metering unit (FCU/FMU)
27. air intake
28. fan blades
Group B
29. attachment and locking mechanisms
30. fittings and brackets
31. cable harness/wiring/switches/plugs
32. cables
33. indicators and warning devices
34. rod assemblies/levers and linkages
35. engine mounting bolts
36. support links
37. seals
38. other specific components
Carry out fifteen of the following maintenance activities:
- removing cowling and containment covers to expose components to be removed
- carrying out fault diagnosis and system checks
- preparing the system for maintenance (such as isolating, draining fluids)
- disconnecting electrical connections
- refitting components in the correct position, orientation and alignment
- removal of bonding
- disconnecting/removing hoses and pipes
- setting and adjusting replaced components (such as travel, working clearance)
- removing securing devices and mechanical fasteners
- supporting equipment to be removed
- making mechanical connections
- dismantling equipment to an appropriate level
- making electrical connections
- covering (protecting) exposed components, wires, pipework or vents
- carrying out bonding
- torque loading as required
- checking components for serviceability
- replenishing fluid systems
- replacing damaged/defective components
- carrying out system functional checks
- replacing single use items such as seals, filters, gaskets
- ensuring that replacement components have the correct part numbers
- fitting blanks, labelling (and storing in the correct location) components that require repair or overhaul
- applying bolt locking methods (such as split pins, wire locking, lock nuts)
- carrying out area inspections prior to task close down
Service/check aircraft power plant, to include carrying out five of the following:
- visually checking power plant for damage and leaks
- checking cowl flap rigging
- checking fastenings/security of all power plant access panels/cowls
- checking indicating and warning systems
- carrying out nozzle rigging
- examining engine mounting bolt assemblies
- checking the starting system
Assist in carrying out an engine ground run test, to include carrying out all of the following:
- checking that the aircraft is correctly parked in authorised position for a ground run
- positioning all required safety equipment prior to ground run
- carrying out prescribed pre-start and start procedures
- ground running an engine in accordance with maintenance manual and local authority requirements/regulations
- checking and recording all specified parameters
- shutting down the engine in accordance with specified procedures
Complete the relevant paperwork, to include one from the following and pass it to the appropriate people:
- job cards/work sheets
- aircraft cabin log
- computer records
- aircraft log book
- aircraft technical log
Carry out maintenance on aircraft power plant in compliance with one of the following:
- Civil Aviation Authority (CAA)/European Aviation Safety Agency (EASA)
- Extended Range Twin-Engine Operations Procedures (ETOPS) (where appropriate)
- Ministry of Defence (MoD)
- Military Aviation Authority (MAA)
- Aerospace Quality Management Standards (AS)
- Federal Aviation Authority (FAA)
- aircraft maintenance manual/approved change documentation (service bulletin)
- manufacturers standards and procedures
Scope Knowledge
Values
Behaviours
You will be able to apply the appropriate behaviours required in the workplace to meet the job profile and overall company objectives, such as:
- strong work ethic
- positive attitude
- team player
- dependability
- responsibility
- honesty
- integrity
- motivation
- commitment