Modifying aircraft propulsion equipment and systems
Overview
This standard identifies the competences you need to modify aircraft propulsion equipment and systems, in accordance with approved procedures. It covers both fixed wing and rotary winged aircraft, where the systems and components may have to be modified for a number of reasons, which could include performance being out of specification, inherent design problems, changes to customer specification, or assembly problems. You will be required to prepare the work area, ensuring that it is safe and free from hazards, to check that the correct component parts requiring modification are available, to obtain all relevant and current documentation, and to obtain the tools and equipment required for the modification, checking that they are in a safe and usable condition. In carrying out the modification operations, you will be required to follow laid-down procedures and to use specific modification leaflets or service bulletins.
The modification requirements will include such items as blade set changes and component upgrades. The modification activities will also include making all necessary checks, including functional checks of systems that have been disturbed during the modification.
Your responsibilities will require you to comply with organisational policy and procedures for the modification activities undertaken and to report any problems with these activities that you cannot personally resolve, or that are outside your permitted authority, to the relevant people. 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 modification techniques and procedures. You will understand the propulsion equipment being modified, and its application, and will know about the components, systems and fastening devices of systems disturbed during the modification operation, in adequate depth to provide a sound basis for carrying out the activities to the required specification.
You will understand the safety precautions required when carrying out the modification operations. You will be required to demonstrate safe working practices throughout, and will understand the responsibility you owe to yourself and others in the workplace.
Note This standard is intended to cover propulsion system modifications of a significant or complex nature, involving the use of a range of techniques and a number of different components. The extent of the complexity will include the size and timescale of the modification, the tolerances required and the difficulty of access. This standard should not be used solely for simple modifications such as changes to, or the addition of, simple pipework, platework or brackets
Performance criteria
You must be able to:
- work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
- obtain and follow the relevant modification specifications and job instructions
- confirm and agree what modifications are to be carried out to meet the specification
- prepare the propulsion equipment/system for the required modification
- carry out the modification using approved materials, methods and procedures
- complete the modification within the agreed timescale
- ensure that the modified propulsion equipment/system meets the specified operating conditions
- deal promptly and effectively with problems within your control and report those that cannot be solved
- leave the aircraft and the system in a safe and appropriate condition, free from foreign object debris and in a condition ready for testing
- complete the relevant documentation, in accordance with organisational requirements
Knowledge and Understanding
You need to know and understand:
- the specific safety precautions to be taken while carrying out modifications on aircraft propulsion equipment/systems and components (including any specific legislation, regulations or codes of practice relating to the activities, equipment or materials)
- the importance of maintenance on and impact upon (extended twin operations procedures) ETOpS systems, legislation and local procedures
- the health and safety requirements of the work area in which you are carrying out the modification activities, and the responsibility these requirements place on you
- COSHH regulations with regard to substances used in the modification process
- the hazards associated with modifying aircraft propulsion equipment/systems, and with the tools and equipment used, and how to minimise them and reduce any risks
- 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 personal protective equipment and clothing (PPE) to be worn during the modification activities
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 various types of drawing and specification that are used during the modification
- how to carry out currency/issue checks on the specifications you are working with
- the reasons why systems and components may require modification
- preparations to be undertaken on the propulsion equipment and system, prior to modification
- the various methods that could be used to modify assemblies (such as adjust, remove and replace, repair and manufacture)
- the techniques that can be used, where appropriate, to modify the propulsion equipment/system (such as fabrication of brackets or covers, mechanical fitting, electrical and electronic or fluid/air/pipe fitting)
- how to identify the components to be used; component identification systems (such as codes and component orientation indicators)
- the methods and procedures to be used for removing and replacing components, and the importance of adhering to these procedures
- the various mechanical fasteners that will be used and their method of installation (including open and blind rivets, 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 importance of applying electrostatic discharge (ESD) procedures when working on sensitive equipment or devices
- the importance of using the specified fasteners for the modification and why you must not use substitutes
- the application of sealants and adhesives within the modification activities and the precautions that must be taken when working with them
- the quality control procedures to be followed during the modification operations
- how to conduct any necessary checks to ensure the accuracy, position, security, function and completeness of the modification
- the methods and equipment used to transport, handle and lift the components into position and how to check that the equipment is within its current certification dates
- how to check that the tools and equipment to be used are correctly calibrated, and are in a safe, tested and serviceable condition
- the importance of ensuring that all tools are used correctly and within their permitted operating range
- the importance of ensuring that all tools, equipment and components are accounted for and returned to their correct location on completion of the modification activities
- the problems associated with carrying out modifications on aircraft propulsion systems and components and the importance of informing the appropriate people of non-conformances
- 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 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 modification activities:
- obtain and use the appropriate documentation (such as job instructions, aircraft modification drawings, technical instructions, planning and quality control documentation, aircraft standards and specifications)
- 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
- provide and maintain a safe working environment for the modification activities
- 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 date
- obtain clearance to work on the aircraft and observe the power isolation and safety procedures
- use safe and approved modification techniques and procedures at all times
- ensure that correct part numbers are used, including (where appropriate) left or right handed parts
- where appropriate, apply electrostatic discharge (ESD) protection procedures
- return all tools and equipment to the correct location on completion of the activities
- dispose of waste items in a safe and environmentally acceptable manner
Modify propulsion equipment/systems from one of the following type of aircraft:
- commercial aircraft
- light aircraft
- military aircraft
- helicopters
Modify aircraft propulsion equipment/systems, to include three from:
- pumps
- engine nacelle
- exhaust system
- thermocouples
- filters
- control mechanisms
- combustion chamber
- electrical modules
- pipework
- compressor blades
- heat exchangers (such as oil, fuel)
- electrical harnesses
- bearings
- turbine blades
- sensors (such as vibration, fire)
- ancillary equipment
- engine suspension mounts
- engine starting equipment
- engine monitoring equipment
- other specific equipment
Carry out the modification, using two of the following methods:
- adjustment
- modify existing components
- remove and replace with new components
- manufacture of new components
Use five of the following methods and techniques during the modification activities:
- dismantling and re-assembling
- hand fitting
- fabricating (such as brackets, clips or covers)
- changing components
- pipe fitting and assembly
- securing and locking components
- repositioning units
- brazing or welding
- electrical fitting and assembly
- adjusting or tuning components
- bonding
- making holes in materials
Use three of the following types of joining method during modifications:
- adhesives/sealants
- locking devices
- rivets
- threaded fasteners
- special fasteners
Modify aircraft propulsion equipment and systems in compliance with one of the following:
- Civil Aviation Authority (CAA)/European Aviation Safety Agency (EASA)
- extended twin operations procedures (ETOpS) (where appropriate)
- Ministry of Defence (MoD)
- Military Aviation Authority (MAA)
- Aerospace Quality Management Standards (AS)
- BS, ISO or BSEN standards and procedures
- Federal Aviation Authority (FAA)
- customer standards and requirements
- aircraft manufacturer's requirements
- company standards and procedures
Complete the relevant paperwork, to include one from the following and pass it to the appropriate people:
- modification records
- log cards
- job cards
- aircraft flight log
- aircraft log book
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