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Removing and replacing components of aircraft environmental systems

URN: SEMAE3148
Business Sectors (Suites): Aeronautical Engineering Suite 3
Developed by: Enginuity
Approved on: 2021

Overview

This standard identifies the competences you need to carry out the removal and replacement of components of aircraft environmental systems, in accordance with approved procedures. It covers both fixed wing and rotary winged aircraft, and includes a range of equipment associated with oxygen equipment, cabin pressurisation equipment, therapeutic masks, air conditioning and heating systems, anti-g, pressurisation of bulkheads, pressure domes, door, canopy and window seals and demisting equipment, avionic cooling, water and waste, ice and rain protection, as applicable to the aircraft type.

You will be required to select the appropriate tools and equipment to use, based on the operations to be performed and the components to be removed. The removal and replacement activities will include taking all necessary safeguards to isolate the system, drain fluids, support and lift removed and replaced parts, and will also include replacing faulty equipment at component or unit level, replenishing fluids, setting and adjusting replaced components, and leaving the system in a safe condition and ready for testing.

Your responsibilities will require you to comply with organisational policy and procedures for the removal and replacement 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 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, 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 removal and replacement techniques and procedures to aircraft environmental equipment and systems. You will understand the removal and replacement methods and procedures, and their application, along with the systems maintenance requirements. You will know how the environmental system and 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 removal and replacement activities, and for ensuring that the equipment is replaced to the required standard. In addition, you will have sufficient knowledge of these components to ensure that they are fit for purpose and meet the specifications, thus providing a sound basis for carrying out the replacement.

You will understand the safety precautions required when working on the aircraft environmental system, especially those for isolating the system. 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 To display competence in this standard, it is necessary to both remove and replace components from aircraft environmental systems. You must remove components; however, you may fit a replacement component where the original was previously removed by another person.

Performance criteria

You must be able to:

  1. work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
  2. follow the relevant aircraft manuals and publications to carry out the required work
  3. establish and where appropriate, mark component orientation for re-assembly
  4. ensure that any stored energy or substances are released safely and correctly
  5. carry out the removal and replacement activities, within the limits of your personal authority
  6. remove and replace the required components, using approved tools and techniques
  7. take suitable precautions to prevent damage to components and the surrounding structure
  8. complete the relevant documentation, in accordance with organisational requirements
  9. label and store (in an appropriate location) components that require repair or overhaul
  10. dispose of waste materials and scrap components in accordance with safe working practices and approved procedures
  11. leave the aircraft and the environmental system in a safe and appropriate condition, free from foreign object debris and in a condition ready for testing

Knowledge and Understanding

You need to know and understand:

  1. the specific safety practices and procedures that you need to observe when working on aircraft environmental systems (including any specific legislation, regulations/codes of practice for the activities, equipment or materials)
  2. the importance of maintenance on, and impact upon (extended twin operations procedures) ETOpS systems, legislation and local procedures
  3. the safety procedures that must be carried out before work is started on removing environmental system components (such as displaying warning notices, draining and depressurising systems)
  4. the hazards associated with removing aircraft environmental system components, and with the tools and equipment used (such as handling fluids, pressurised systems, misuse of tools) and how to minimise them and reduce any risks
  5. 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
  6. the protective equipment that you need to use for both personal protection (PPE) and protection of the aircraft
  7. how to extract and use information from aircraft manuals, history/maintenance reports, flight logs, charts, circuit and physical layouts, specifications, symbols used in aircraft environmental systems and other documents needed in the removal and replacement process
  8. how to carry out currency/issue checks on the specifications you are working with
  9. terminology used in aircraft environmental systems and the use of diagrams and associated symbols
  10. the various types of pipes and components that make up the aircraft environmental system (such as rigid pipes, flexible hoses, pipe connectors, pipe sealing and supporting devices, compressors, pumps, pressure intensifiers, mechanical and electrical control devices)
  11. the principles of operation of the aircraft environmental system being worked on and the performance characteristics and function of the components within the circuit
  12. the techniques used to remove components from aircraft environmental systems without damage to components or surrounding structure (such as release of pressures/force, draining of fluids, proof marking, extraction of components, and the need to protect the circuit integrity by fitting blanking plugs and labelling exposed circuits)
  13. the various mechanical fasteners to be removed and replaced and their method of removal and replacement (such as threaded fasteners, special securing devices)
  14. the various types of electrical connector that are used, methods of unlocking, orientation indicators and locating and locking in of the connections
  15. the importance of applying electrostatic discharge (ESD) procedures when working on sensitive equipment/device
  16. methods of lifting, handling and supporting the components/equipment during removal and replacement activities
  17. the importance of ensuring that the work area is free from dirt, swarf and foreign object damage and of ensuring that any exposed components or pipe ends are correctly covered/protected
  18. recognition of contaminants and the problems they can create; the effects and likely symptoms of contamination in the system (especially hydrocarbons in oxygen systems)
  19. the need to correctly label and store components that require repair or overhaul, and to check that replacement components have the correct part/identification markings
  20. how to re-connect components into the system (such as the use of gaskets/seals and jointing/sealing compounds; ensuring the correct tightness of pipe fittings and valve connections; eliminating stress on pipework/connections; ensuring that pipework is supported at suitable intervals; carrying out visual checks of all components; checking security of joints and that the system is safe to re-fill/pressurise)
  21. how to make adjustments to components/assemblies to ensure that they function correctly (such as flow and pressure settings) and their effect on the system, travel and working clearance
  22. why electrical bonding is critical and why it must be both mechanically and electrically secure
  23. why securing devices need to be tightened to the correct torque, locked and labelled and the different methods that are used
  24. the tools and equipment used in the removal and replacement activities, and their calibration/care and control procedures

  25. the need to control and account for all tools and equipment used during the removal and replacement activity and what to do if a tool or piece of equipment is unaccounted for on completion of the activities

  26. the problems that can occur with the removal/replacing operations and how these can be overcome

  27. 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
  28. the procedure for the safe disposal of waste materials, scrap components, oils and fluids
  29. the extent of your own authority and to whom you should report if you have a problem that you cannot resolve

Scope/range

Scope Performance

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  1. Carry out all of the following during the removal and replacement activity:

    1. obtain clearance to work on the aircraft and observe all relevant safety procedures
    2. obtain and use the appropriate documentation (such as job instructions, aircraft manuals, technical instructions, and other relevant maintenance documentation)
    3. 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
    4. obtain the correct tools and equipment for the activity, and check that they are in a safe, tested and usable condition and within current certification/calibration date
    5. ensure the safe isolation and draining/depressurisation of the environmental equipment before breaking into the system
    6. ensure that all relevant safety devices and mechanical/physical locks are in place (where appropriate)
    7. where appropriate, apply electrostatic discharge (ESD) protection procedures
    8. use approved removal and replacement techniques and procedures at all times
    9. ensure that components and surrounding structures are maintained free from damage and foreign objects
    10. return all tools and equipment to the correct location on completion of the activities

  2. Remove components from three of the following aircraft environmental systems and replace components from three of the following aircraft environmental systems:

    1. oxygen systems                       
    2. cabin pressurisation systems
    3. ice protection
    4. air conditioning systems    
    5. pressurised bulkheads
    6. rain protection
    7. cabin heating and cooling  
    8. pressure domes    
    9. anti-g
    10. avionic cooling systems 
    11. demisting equipment

  3. During the activities identified in scope 2 above, you must cover the removal and replacement of the following:

Major environmental system components: Remove and replace four of the following:

1.  reservoirs/supply tanks     
2.  air receivers  
3.  compressor 
4.  regulators
5.  accumulators      
6.  diffusers
7.  pumps 
8.  cylinders
9.  pressure intensifiers  
10.  charging bottles    
11.  water extractors
12.  humidifier
13.  cold air units/air cycle machines  
14.  heat exchangers     
15.  pressure controllers
16.  safety devices
17.  air-conditioning packs   
18.  actuating mechanisms
19.  sensors
20.  oxygen generation components     
21.  valves (such as by-pass, shut-off, check, relief, temperature control, outflow, anti-g)pressure
22.  face mask and allied equipment              
23.  environmental seals and sealants       
24.  ozone converters
25.  door, window and canopy seals      
26.  other specific components

Other environmental system components: Remove and replace four of the following:
27. filters                          
28. hoses      
29. gauges
30. strainers including water separator 
31. gaskets and seals       
32. electrical controls (solenoids, motors, switches)
33. earthing straps/jumper braids  
34. unions and couplings            
35. rigid pipework/ducting

  1. Carry out all of the following removal and replacement activities:

    1. releasing stored pressure (where applicable)       
    2. replacing all 'lifed' items (seals, filters, gaskets)
    3. disconnecting electrical connections               
    4. positioning and aligning replaced components
    5. disconnecting/removing hoses and pipes     
    6. making mechanical connections
    7. ensuring that any part-dismantled components are secure/supported 
    8. making electrical connections             
    9. tightening fastenings to the required torque
    10. applying and removing covering/protection to exposed components, wires, pipework or vents
    11. use of ground support equipment
    12. checking components for serviceability
    13. replacing damaged/defective components
    14. labelling (and storing in the correct location) components that require repair or overhaul
    15. applying bolt locking methods (such as split pins, wire locking, lock nuts)
    16. fitting blanks to open systems to prevent entry of contaminating debris
    17. securing components using mechanical fasteners and threaded devices
    18. re-pressurising the system (where applicable)
    19. applying bolt locking methods (such as split pins, wire locking, lock nuts)

  2. Remove and replace environmental system components in compliance with one of the following:

    1. Civil Aviation Authority (CAA)/European Aviation Safety Agency (EASA)
    2. extended twin operations procedures (ETOpS) (where appropriate)
    3. Ministry of Defence (MoD)
    4. Military Aviation Authority (MAA)
    5. Aerospace Quality Management Standards (AS)
    6. Federal Aviation Authority (FAA)
    7. BS, ISO or BSEN standards and procedures
    8. customer standards and requirements
    9. company standards and procedures
    10. aircraft manufacturer's requirements

  3. Complete the relevant paperwork, to include one from the following and pass it to the appropriate people:

    1. job cards
    2. computer records
    3. aircraft service/flight log
    4. aircraft log book
    5. permit to work/formal risk assessment

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

Skills

Glossary

Links To Other NOS

External Links

Version Number

3

Indicative Review Date

2024

Validity

Current

Status

Original

Originating Organisation

Enginuity

Original URN

SEMAE3148

Relevant Occupations

Engineer, Engineering, Engineering and Manufacturing Technologies, Engineering Technicians

SOC Code

5234

Keywords

Aeronautical; engineering; aircraft environmental systems; oxygen equipment; therapeutic masks; air conditioning; heating systems; pressure domes