Maintaining engine controls on aircraft
Overview
This standard identifies the competences you need to carry out maintenance activities on aircraft engine control systems, in accordance with the approved aircraft maintenance manual, approved change documentation (service bulletin) and airworthiness requirements. It includes units and components which govern operation of the engine, and includes units and components that are interconnected for emergency shutdown. The maintenance activities will include the removal, fitting and testing of a range of engine control components. You will be required to select the correct tools and equipment to use, based on the operations to be performed and the components to be removed, fitted and tested. The aircraft engine control components will include items such as linkages, cables, levers, pulleys, switches and wiring. 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 engine control systems. You will understand the removal, fitting and testing methods and procedures, and their application, along with the aircraft engine control system maintenance requirements. You will know how the aircraft engine controls function, 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 equipment is maintained to the required standard.
You will understand the safety precautions required when working on aircraft engine control systems, especially those for isolating the equipment. 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.
Notes:
- This standard is designed to cover the practical experience requirements of the Airline Transport Association (ATA) Chapter 76 Engine Controls.
- To display competence in this standard, it is necessary to both remove and fit aircraft engine control system 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 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 engine control systems (including any specific legislation, regulations/codes of practice for the activities, equipment or materials)
- the importance of maintenance on aircraft engine controls, and impact upon Extended Range Twin-Engine Operations Procedures (ETOPS) systems, Electrical Wiring Interconnect Systems (EWIS), legislation and local procedures
- hazards associated with removing, fitting and testing aircraft engine control system components, and with the tools and equipment used, and how to minimise them and reduce any risk
- 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 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 maintenance manuals, log books, flight logs, and other documents needed in the maintenance process
- how to carry out currency/issue checks on the specifications you are working with
- terminology used in aircraft engine control systems, and the use of system diagrams and associated symbols
- the principles of operation of the aircraft engine control system being worked on, and the function of the various units/components within the system
- the techniques used to remove components from aircraft engine control systems without damage to the components or surrounding structure (such as proof marking, extraction 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
- the importance of applying electrostatic discharge (ESD) avoidance procedures when working on sensitive equipment or devices
- methods of lifting, handling and supporting the components/equipment during the maintenance activities
- methods of checking that components are fit for purpose, and how to identify defects and wear characteristics
- the need to replace items such as seals and gaskets
- 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 replace and reconnect components into the system (such as ensuring the correct orientation, position and alignment; tightening securing devices to the required torque; replacing locking and securing devices; eliminating stress on pipework/connections; ensuring that pipework and cables are correctly supported at suitable intervals; carrying out visual checks of all components)
- how to make adjustments to components/assemblies to ensure that they function correctly (such as setting working clearance, setting travel)
- why electrical bonding is critical, and why it must be both mechanically and electrically secure
- how to carry out routine checks and servicing of the aircraft engine control system
- 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 types of test to be carried out on the aircraft engine control system, and the test equipment to be used
- the methods and procedures to be used to carry out the various tests on the engine control system
- the importance of carrying out the tests in the specified sequence, checking all readings and movements at each stage
- how to record the results of the checks and tests, and the documentation that must be used
- how to analyse the test results and make valid decisions about the acceptability of the engine control systems
- the procedures to be followed if the equipment or system fails to meet the test specification
- 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 problems that can occur with the aircraft engine control system maintenance operations and how these can be overcome
- 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
- the procedure for the safe disposal of waste materials and scrap components
- 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 engine control 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 that the relevant safety devices and mechanical/physical locks are in place (where appropriate)
- ensure the safe isolation of the engine control system before commencing work on the equipment
- where appropriate, apply electrostatic discharge (ESD) avoidance procedures
- 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 maintenance on two of the following parts of the aircraft engine control systems:
- engine synchronizing
- emergency shutdown
- mixture control
- engine control system wiring
- power control
- variable air intake
- throttles
- nozzle control system
- start system
- fuel/air control
- reverse thrust
- engine bypass
Remove and fit four different aircraft engine control system components from the following:
- cables and pulleys
- levers and linkages
- turnbuckles
- sensors
- connecting rods
- actuators
- jack screws
- cables/harness/wiring
- position transmitters
- motors
- locks and stops
- plugs/sockets/switches
- start valve
- servos
- bell cranks
- fuel control/meter unit (FCU/FMU)
- other specific components
Carry out fifteen of the following maintenance activities:
- removing access panels and covers to expose components to be removed
- carrying out fault diagnosis and system checks
- preparing the system for maintenance (such as isolating)
- disconnecting electrical connections
- refitting components in the correct position, orientation and alignment
- removing securing devices and mechanical fasteners
- supporting equipment to be removed
- setting and adjusting replaced components (such as freedom of movement, cable tension)
- dismantling equipment to an appropriate level
- covering (protecting) exposed components, wires, pipework or vents
- making mechanical connections
- making electrical connections
- disconnecting/reconnecting bonding leads
- checking components for serviceability
- torque loading as required
- replacing damaged/defective components
- carrying out functional checks of the system
- ensuring that replacement components have the correct part numbers
- 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
Carry out three of the following types of test/check on the aircraft engine control systems:
- rig thrust lever
- rig/check reverse thrust
- rig RPM control
- rig/check bypass
- rig mixture high pressure cock lever
- check cable tension
- rig power lever
- adjust pedestal micro switches
- check control synchronization (multi-engine)
- check range and sense of operation of controls
- engine run
- `special-to-type' tests
- rig/check variable intake
- built in test equipment (BITE) test
Using two of the following:
15. built in test equipment (BITE)
16. ground support equipment
17. 'special-to-type' test equipment
18. aircraft power supply/displays and gauges
19. use of safety locks
20. measuring equipment
Complete the relevant paperwork, to include one from the following and pass it to the appropriate people:
- job cards/work sheets
- computer records
- aircraft technical log
- aircraft cabin log
- aircraft log book
Carry out maintenance on aircraft engine control systems 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