Carrying out tests on aircraft power transmission systems
Overview
This standard identifies the competences you need to test aircraft power transmission systems, in accordance with approved procedures. It covers rotary winged aircraft and includes units and components associated with the aircraft power transmission systems to be tested, such as drive shafts, drive shaft supports, gearbox assemblies, couplings, mechanical fasteners, accelerometers, vibration monitoring equipment, and main and tail rotor assemblies.
You will be required to select the appropriate tools and equipment to use, based on the operations to be performed and the systems to be tested. Testing activities will include making all necessary checks and adjustments to ensure that components are correctly positioned and aligned, functional testing of power transmission systems, including rotor heads, drive trains and gear boxes.
Your responsibilities will require you to comply with organisational policy and procedures for the aircraft power transmission testing 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 ensure that all tools, equipment and materials used are correctly accounted for on completion of the testing activities, and that all necessary 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 test procedures to aircraft power transmission systems. You will understand the aircraft power transmission system under test, and its application, and will know about the tools and equipment used, and the testing requirements, in adequate depth to provide a sound basis for carrying out the activities and for ensuring that the tested system performs to the required specification.
You will understand the safety precautions required when carrying out the testing activities and when using the associated tools and equipment. You will be required to demonstrate safe working practices throughout and will understand the responsibility you owe to yourself and others in the workplace.
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 appropriate procedures for use of tools and equipment to carry out the required tests
- set up and carry out the tests using the correct procedures and within agreed timescales
- record the results of the tests in the appropriate format
- review the results and carry out further tests if necessary
- leave the aircraft and the system in a safe and appropriate condition, free from foreign object debris
Knowledge and Understanding
You need to know and understand:
- the specific safety practices and procedures that you need to observe when testing aircraft power transmission systems (including any specific legislation, regulations/codes of practice for 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 where you are carrying out the activities and the responsibility these requirements place on you
- the safety procedures that must be carried out before work is started on the aircraft
- 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 clothing and equipment (PPE) to be worn and where it can be obtained
- hazards associated with testing aircraft power transmission systems, and with the tools, materials and equipment used (such as working with oil and grease, moving/rotating parts) and how to minimise them and reduce any risks
- the correct operating procedures of the power transmission system being tested
- electrical bonding specifications and their importance
- how to obtain the required test schedules and specifications for the aircraft and power transmission system being tested, and how to check their currency and validity
- how to read and interpret test schedules and specifications and from whom you can seek assistance if you have problems or issues regarding the test schedules or specifications
- the types of test to be carried out on the aircraft power transmission systems (such as alignment checks, balance checks, freedom and range of movement checks, ground run tests, leak checks, safety interlock tests)
- the methods and procedures to be used to carry out the various tests on the power transmission systems
- test equipment to be used and its selection for particular tests; calibration of test equipment (where applicable); and the currency and issue checks to be made
- the techniques, methods and procedures to be used during the tests
- why equipment and tool control is critical and what to do if a piece of equipment/tools are unaccounted for on completion of the testing activities
- the principle of operation of the power transmission system under test and the function of the individual components within the system
- the importance of carrying out the tests in the specified sequence, checking all readings, movements and pressures at each stage
- the importance of ensuring that pressure is maintained and the methods used to detect leaks and faults within the system
- how to record the results of each individual test and the documentation that must be used for this
- from whom to seek authorisation if you need to alter or change the test procedures
- how to analyse the test results and how to make valid decisions about the acceptability of the aircraft
- the procedures to be followed if the equipment or system fails to meet the test specification
- problems that can occur with the testing activities and how they can be overcome
- the problems that may cause errors or discrepancies in/with the test results and how to avoid these
- any required environmental controls relating to the testing
- the documentation to be completed at the end of the testing activities
- 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 testing of the aircraft power transmission systems:
- obtain and use the appropriate documentation (such as job instructions, aircraft power transmission system test procedures, quality control documentation, history sheets, flight logbook, 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 testing 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 all relevant isolation and safety procedures
- ensure that safe working distance procedures are set up (where appropriate)
- carry out the tests using the specified techniques and procedures
- make any permitted adjustments to components and equipment to bring the system to the specification requirements
- return all tools and equipment to the correct location on completion of the testing activities
Carry out testing on three of the following aircraft power transmission system assemblies/components:
- drive shaft/high speed shaft
- swash plate
- couplings
- intermediate gear box
- tail rotor assembly
- nose/forward gear box
- main gear box
- tail gear box
- accelerometer
- flexi couplings
- drive shaft support
- main rotor assembly
Test aircraft power transmission system components, using appropriate tools or test equipment, to include three of the following:
- built-in test equipment (BITE)
- use of safety locks
- 'special-to-type' test equipment
- dial test indicator
- plumb and bob
- optical site instruments
- laser alignment
- feeler/slip gauges
- jigs/fixture
- clinometers
- 'go/no-go' gauge
- lay straight wires
- vibration analysis equipment
Carry out five of the following types of test:
- visual inspection
- built-in test equipment (BITE)
- ground run tests
- functional check
- timings
- freedom and range of movement
- gear box alignment (main, tail, intermediate)
- tension adjuster check
- leak test
- safety interlock test
- vibration analysis
- drive shaft/high speed shaft alignment
- main rotor rigging
- phasing check
- tail rotor rigging
- 'special-to-type' tests
- static or dynamic balancing
Including the following:
18. a full system test that incorporates three of the above tests
Carry out tests 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)
- customer standards and requirements
- Federal Aviation Authority (FAA)
- company standards and procedures
- BS, ISO or BSEN standards and procedures
- specific system requirements
- aircraft manufacturer's requirements
Complete the relevant paperwork, to include one from the following, indicating the results of the tests and pass it to the appropriate people:
- computer records
- test records
- job cards
- aircraft service/flight log
- aircraft log book
- 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