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Maintaining flight control systems on aircraft

URN: SEMAE3311
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 flight control systems, in accordance with the approved aircraft maintenance manual, approved change documentation (service bulletin) and airworthiness requirements. It includes units and components which manually control the flight, attitude and characteristics of the aircraft. The maintenance activities will include the removal, fitting and testing of a range of flight 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 components will include items such as ailerons and tabs, horizontal stabilizer, elevator, rudder, flaps, spoilers/drag devices, gust locks and dampers, lift augmenting system 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 flight control systems. You will understand the removal, fitting and testing methods and procedures, and their application, along with the aircraft flight control system maintenance requirements. You will know how the aircraft flight 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 flight control systems, especially those for isolating the equipment, and lifting and handling control components. 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 27 Flight Controls.
  2. To display competence in this standard, it is necessary to both remove and fit aircraft flight 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:

  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 flight control systems (including any specific legislation, regulations/codes of practice for the activities, equipment or materials)
  2. the importance of maintenance on aircraft flight control systems, and impact upon ETOPS systems, Electrical Wiring Interconnect Systems (EWIS), legislation and local procedures
  3. hazards associated with removing, fitting and testing aircraft flight control system components, and with the tools and equipment used, and how to minimise them and reduce any risk
  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 protective equipment that you need to use for both personal protection (PPE) and protection of the aircraft

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

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

  8. 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

  9. how to extract and use information from aircraft maintenance manuals, log books, flight logs, and other documents needed in the removal and replacement process
  10. how to carry out currency/issue checks on the specifications you are working with
  11. terminology used in aircraft flight control systems, and the use of system diagrams and associated symbols
  12. the principles of operation of the aircraft flight control system being worked on, and the function of the various units/components within the system
  13. the techniques used to remove components from aircraft flight control systems without damage to the components or surrounding structure (such as release of pressures/force, proof marking, extraction of components), and the need to protect the system integrity (by fitting blanking plugs and ensuring that exposed components are correctly covered/protected)
  14. the various mechanical fasteners to be removed and replaced (such as threaded fasteners, special securing devices), and their method of removal and replacement 
  15. the various types of electrical connector that are used, methods of unlocking, orientation indicators and locating and locking-in of the connections
  16. the importance of applying electrostatic discharge (ESD) avoidance procedures when working on sensitive equipment or devices
  17. methods of lifting, handling and supporting the components/equipment during the maintenance activities
  18. methods of checking that components are fit for purpose, and how to identify defects and wear characteristics
  19. the need to replace items such as seals and gaskets
  20. 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
  21. how to replace and reconnect components into the system (such as ensuring 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)
  22. how to make adjustments to components/assemblies to ensure that they function correctly (such as setting working clearance, setting travel, preloading bearings)
  23. why electrical bonding is critical and why it must be both mechanically and electrically secure
  24. the purpose of symmetry and rigging checks; how they are carried out; how to locate the rigging points and faces; and the use of incidence boards
  25. how to carry out routine checks and servicing of the aircraft flight control system
  26. 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)
  27. the types of test to be carried out on the aircraft flight control system and the test equipment to be used
  28. the methods and procedures to be used to carry out the various tests on the flight control system
  29. the importance of carrying out the tests in the specified sequence, checking readings/movements at each stage
  30. how to record the results of each individual test and the documentation that must be used
  31. how to analyse the test results and make valid decisions about the acceptability of the flight control systems
  32. the procedures to be followed if the equipment or system fails to meet the test specification 
  33. 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
  34. the problems that can occur with flight control system maintenance operations, and how these can be overcome
  35. 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
  36. the procedure for the safe disposal of waste materials and scrap components
  37. the extent of your own authority and to whom you should report if you have problems that you cannot resolve

Scope/range

Scope Performance

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  1. Carry out all of the following during the maintenance of the aircraft flight control 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 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 that the relevant safety devices and mechanical/physical locks are in place (where appropriate)
    6. ensure the safe isolation of the control system before commencing work on the equipment
    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 aircraft flight control systems:

    1. spoiler, drag devices and variable aerodynamic fairings (such as air brakes, speed brakes)
    2. ailerons/tailerons and tab 
    3. elevators and trim tabs        
    4. gust lock and damper
    5. flaps/slats/flaperons      
    6. rudder/yaw/ruddervator and tab   
    7. throttles
    8. lift augmenting devices  
    9. horizontal stabilisers/stabilator/canards
    10. thrust reverser
    11. nose and body steering  
    12. spoilers, air brakes, lift dumpers 
    13. propeller controls
    14. other specific flight control system

  3. Remove and fit six different aircraft flight control system components (at least three must be from group A):

Group A

1.  horizontal stabiliser    
2.  trim wheels       
3.  spoilers
4.  elevator                      
5.  reaction control nozzles  
6.  drag devices
7.  aileron                     
8.  powered flying control units  
9.  gradient boxes
10.  rudder                 
11.  automatic stall recovery device    
12.  actuators
13.  flaps rudder pedals       
14.  auxiliary controls        
15.  mixer units
16.  flap selectors                  
17.  torque tubes              
18.  artificial feel units
19.  control columns          
20.  boosters      
21.  auxiliary servo equipment (ASE)
22.  stick shaker units        
23.  tab control wheel     
24.  primary servo jack
25.  air/speed brake selectors 
26.  control surfaces
27.  primary flight computers (including actuator control electronic - ACE)
28.  other specific component

Group B
29. cables and pulleys     
30. levers and linkages  
31. turnbuckles    
32. locks and stops
33. connecting rods     
34. pedal shakers
35. jack screws
36. bell cranks
37. position transmitters  
38. actuators/motors/servos  
39. sensors        
40. reaction control ducting
41. 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, releasing stored pressure)
    4. disconnecting electrical connections      
    5. refitting components in the correct position, orientation and alignment
    6. removal of bonding             
    7. removing securing devices and mechanical fasteners
    8. setting and adjusting replaced components (such as freedom of movement, cable tension)
    9. supporting equipment to be removed           
    10. dismantling equipment to an appropriate level  
    11. making mechanical connections
    12. covering (protecting) exposed components, wires, pipework or vents 
    13. making electrical connections
    14. carrying out bonding
    15. checking components for serviceability   
    16. torque loading as required
    17. replacing damaged/defective components      
    18. carrying out functional checks of the system
    19. ensuring that replacement components have the correct part numbers
    20. labelling (and storing in the correct location) components that require repair or overhaul
    21. applying bolt locking methods (such as split pins, wire locking, lock nuts)
    22. carrying out area inspections prior to task close down

  2. Carry out five of the following types of test/check on the aircraft flight control systems:

    1. functional                   
    2. built in test equipment (BITE) 
    3. ground run tests
    4. rigging check                
    5. timings               
    6. range and freedom of movement
    7. static friction check     
    8. cable tension check  
    9. leak test
    10. `special-to-type' tests
    11. safety interlock test

Using two of the following:
12. built in test equipment (BITE)  
13. ground support equipment      
14. `special-to-type' test equipment
15. aircraft power source/displays and gauges 
16. use of safety locks       
17. measuring equipment

  1. 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

  2. Carry out maintenance on aircraft flight control 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

SEMAE3311

Relevant Occupations

Engineer, Engineering, Engineering and Manufacturing Technologies, Engineering Technicians

SOC Code

5234

Keywords

engineering; aeronautical; aircraft flight; control systems; maintenance manual; service bulletin; ailerons and tabs; horizontal stabilizer; elevator; rudder; flaps; spoilers/drag devices; gust locks and dampers; lift augmenting system components