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Maintaining fire protection systems on aircraft

URN: SEMAE3310
Business Sectors (Suites): Aeronautical Engineering Suite 3
Developed by: Enginuity
Approved on: 2021

Overview

This standard identifies the competences you need to carry out maintenance activities on aircraft fire protection systems, 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 both fixed and portable units and components which detect and indicate fire or smoke, and which store and distribute fire extinguishing agents to all protected areas of the aircraft. The maintenance activities will include the removal, fitting and testing of a range of fire protection system components. You will be expected to use the approved procedure for correctly isolating the system or fitting extinguishing trip defeat mechanisms before testing/trouble shooting the protection system circuit. 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 fire protection systems. You will understand the removal, fitting and testing methods and procedures, and their application, along with the fire protection systems 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 equipment is maintained to the required standard.

You will understand the safety precautions required when working on aircraft fire protection systems. 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:

  1. This standard is designed to cover the practical experience requirements of the Airline Transport Association (ATA) Chapter 26 Fire Protection.
  2. To display competence in this standard, it is necessary to both remove and fit aircraft fire protection 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:

  1. work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
  2. follow the relevant maintenance schedules to carry out the required work
  3. carry out the maintenance activities within the limits of your personal authority
  4. carry out the maintenance activities, and replace components in the specified sequence and in an agreed timescale
  5. report any instances where the maintenance activities cannot be fully met or where there are identified defects outside the planned schedule
  6. complete relevant documentation in accordance with organisational requirements
  7. dispose of waste materials in accordance with safe working practices and approved procedures
  8. leave the aircraft and system 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:

  1. the specific safety practices and procedures that you need to observe when working on aircraft fire protection systems (including any specific legislation, regulations/codes of practice for the activities, equipment or materials)
  2. the importance of maintenance on aircraft fire protection systems, and impact upon Extended Range Twin-Engine Operations Procedures (ETOPS) systems, Electrical Wiring Interconnect Systems (EWIS), legislation and local procedures
  3. 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)
  4. 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
  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 hazards associated with carrying out maintenance activities on aircraft fire protection systems, and with the tools and equipment used, and how to minimise them and reduce any risk

  7. the protective equipment that you need to use for both personal protection (PPE) and protection of the aircraft

  8. what constitutes a hazardous voltage and how to recognise victims of electric shock

  9. how to reduce the risks of a phase to earth shock (such as insulated tools, rubber matting and isolating transformers)

  10. 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

  11. how to extract and use information from aircraft manuals, log books, flight logs, charts, circuit and physical layouts, specifications, symbols used in aircraft fire protection systems, and other documents in the maintenance activities
  12. how to carry out currency/issue checks on the specifications you are working with
  13. terminology used in aircraft fire protection systems, and the use of system diagrams and associated symbols
  14. the various types of pipe and component that make up the aircraft fire protection system (such as rigid pipes; hoses; pipe connectors; pipe sealing and supporting devices; valves; pumps; mechanical and electrical control devices)

  15. the principles of operation of the aircraft fire protection system being worked on (such as thermal switch, thermocouple, continuous loop, continuous element; fire detection, and warning; sources and types of extinguishing agent; extinguishing agent control and distribution)

  16. the techniques used to remove components from aircraft fire protection systems without damage to the components or surrounding structure

  17. the various mechanical fasteners to be removed and replaced, and their methods of removal and replacement (such as threaded fasteners, special securing devices)
  18. the various types of electrical connector that are used, methods of unlocking, orientation indicators and locating and locking-in of the connections
  19. the importance of applying electrostatic discharge (ESD) avoidance procedures when working on sensitive equipment or devices
  20. the importance of ensuring that any exposed components, wires or pipe ends are correctly covered/protected
  21. 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
  22. how to fit components into the circuit (such as the use of gaskets/seals and jointing/sealing compounds; ensuring the correct tightness of pipe fittings and connections; eliminating stress on pipework/connections; carrying out visual checks of all components)
  23. how to make adjustments to components/assemblies to ensure that they function correctly
  24. why securing devices need to be tightened to the correct torque, locked and labelled, and the different methods that are used
  25. the tools and equipment used in the maintenance activities, and their calibration/care and control procedures
  26. 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
  27. how to carry out routine checks and servicing of the aircraft fire detection system (including checking content of fire bottles and extinguishers, replacing fire bottle squib, checking operation of warning system, checking operation of smoke detectors)
  28. the types of test to be carried out on the aircraft fire protection system, and the test equipment to be used
  29. the methods and procedures to be used to carry out the various tests on the fire protection system
  30. the importance of carrying out tests in the specified sequence, checking readings and movements at each stage
  31. how to record the results of each individual test, and the documentation that must be used
  32. how to analyse the test results, and how to make valid decisions about the acceptability of the aircraft indicating and recording systems 
  33. the procedures to be followed if the equipment or system fails to meet the test specification
  34. the procedure for the safe disposal of waste materials and scrap components
  35. the extent of your own authority and to whom you should report if you have problems that you cannot resolve

Scope/range

Scope Performance

​

  1. Carry out all of the following during the maintenance of the aircraft fire protection system:

    1. ensure that appropriate authorisation to work on the aircraft is obtained, and observe all relevant isolation and safety procedures
    2. obtain and use the correct documentation (such as job instructions, technical instructions, aircraft manuals and maintenance documentation)
    3. 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
    4. 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
    5. ensure the safe isolation of the fire protection equipment before breaking into the system circuit
    6. ensure that the relevant safety devices and mechanical/physical locks are in place (where appropriate)
    7. where appropriate, apply electrostatic discharge (ESD) avoidance procedures
    8. use approved removal, fitting and testing techniques and procedures at all times
    9. return tools and equipment to the correct storage location on completion of the activities
    10. ensure that work carried out is correctly documented and recorded
    11. ensure that any outstanding tests are correctly documented

  2. Carry out maintenance on two of the following parts of an aircraft fire protection system:

    1. detection         
    2. indicating     
    3. extinguishing  
    4. explosion suppression

  3. Carry out maintenance on fire protection systems operated by two of the following:

    1. thermal switch
    2. thermocouple
    3. continuous loop 
    4. continuous element

  4. Remove and fit four different aircraft fire protection system components (at least two must be from group A):

Group A

1.  smoke detectors (optical)    
2.  overheat detectors   
3.  thermal switches
4.  rate-of-temperature-rise detectors   
5.  fibre-optic detectors      
6.  control valves
7.  radiation sensing detectors   
8.  sprays/nozzles  
9.  fire wire
10.  carbon monoxide detectors    
11.  fire bottles
12.  combustible mixture detectors     
13.  pumps

Group B
14. pipes and hoses         
15. sensors/transmitters 
16. gauges
17. pyrotechnic cartridges          
18. wiring/switches/plugs
19. foam suppressant              
20. nitrogen equipment
21. other specific components

  1. Carry out fifteen of the following maintenance activities:

    1. removing access panels and covers to expose components to be removed
    2. carrying out fault diagnosis and system checks
    3. preparing the system for maintenance (such as isolating, fitting trip defeat mechanisms)
    4. inspecting on board fire protection equipment     
    5. refitting components in the correct position, orientation and alignment
    6. disconnecting electrical connections                                    
    7. removal of bonding                                   
    8. setting and adjusting replaced components (such as travel, working clearance)
    9. disconnect/removing hoses and pipes                                 
    10. removing securing devices and mechanical fasteners  
    11. making mechanical connections
    12. supporting equipment to be removed          
    13. making electrical connections
    14. dismantling equipment to an appropriate level     
    15. carrying out bonding
    16. covering (protecting) exposed components, wires, pipework or vents
    17. torque loading as required
    18. purging and replenishing extinguishing agent
    19. checking components for serviceability           
    20. carrying out a system functional check
    21. replacing damaged/defective components
    22. replacing single use items such as seals, filters, gaskets
    23. ensuring that replacement components have the correct part numbers
    24. fitting blanks, labelling and storing in the correct location components that require repair or overhaul
    25. applying bolt locking methods (such as split pins, wire locking, lock nuts)
    26. carrying out area inspections prior to task close down

  2. Service/check the aircraft fire protection system, to include carrying out three of the following:

    1. checking fire bottle contents
    2. checking operation of fire warning system
    3. checking cabin fire extinguisher contents
    4. checking cargo bays fire extinguishing system
    5. checking toilet smoke detector system
    6. inspecting engine fire wire detection system
    7. checking auto-shutdown function if installed (such as APU)
    8. function testing of fire bottle activation circuits

  3. Carry out one of the following tests on the aircraft fire protection system:

    1. smoke test                
    2. built in test equipment (BITE) test
    3. heat test                   
    4. 'special-to-type' tests
    5. 'no volts' test

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

    1. job cards/work sheets
    2. computer records
    3. aircraft technical log
    4. aircraft cabin log
    5. aircraft log book

  5. Carry out maintenance on aircraft fire protection systems in compliance with one of the following:

    1. Civil Aviation Authority (CAA)/European Aviation Safety Agency (EASA)
    2. Extended Range Twin-Engine 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. aircraft maintenance manual/approved change documentation (service bulletin)
    8. 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

Skills

Glossary

Links To Other NOS

External Links

Version Number

3

Indicative Review Date

2024

Validity

Current

Status

Original

Originating Organisation

Enginuity

Original URN

SEMAE3310

Relevant Occupations

Engineer, Engineering, Engineering and Manufacturing Technologies, Engineering Technicians

SOC Code

5234

Keywords

engineering; aeronautical; isolating; fitting; extinguishing; trip defeat; mechanisms; protection system circuit; replacements; airworthiness; maintenance techniques