Testing aircraft power transmission systems
Overview
This standard identifies the competences you need to test aircraft power transmission systems, in accordance with approved procedures. You will be required to test transmission systems including drive shafts, flexible couplings, accelerometers, gearbox assemblies (main, intermediate and tail) and main and tail rotor heads. 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. The complexity of tests involved will include the functional testing of all power transmission systems, including rotor heads, drive trains and gear boxes, both with and without faults.
Your responsibilities will require you to comply with organisational policy and procedures for the power transmission tests undertaken and to report any problems with the testing 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 and instruction, taking full 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 aircraft power transmission test procedures. You will understand the transmission system being tested, and its application, and will know about the testing requirements, in adequate depth to provide a sound basis for carrying out the activities, correcting faults and ensuring that the tested system functions to the required specification.
You will understand the safety precautions required when carrying out the testing 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.
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 work area 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:
- 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 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 hazards associated with testing aircraft power transmission systems and with the tools and equipment used and how to minimise them and reduce any risks
- the protective clothing and equipment (PPE) to be worn and where it can be obtained
- the correct operating procedures of the system being tested
- electrical bonding specifications and their importance
- how to obtain the required test schedules and specifications for the aircraft transmission system being tested and how to check their currency and validity
- how to read and interpret the specifications and from whom you can seek assistance if you have problems or issues regarding the test schedules or specifications
- the methods and procedures to be used to carry out the various transmission tests
- the various types of equipment/component that make up the test equipment (such as clinometer, laser sight, optical sight, jigs and fixtures, slip gauges, go/no-go gauges) and their selection for particular tests
- calibration of test equipment (where applicable) and how to carry out currency/issue checks of documentation
- methods of breaking down and testing systems, while ensuring that contamination of the system is avoided and that the system, equipment, surrounding airframe and components are not damaged
- the need to apply engine power in incremental stages and the need to check all readings, temperatures and pressures at each stage
- the fault finding techniques to be used if the system fails the tests
- reconnecting system equipment when testing is completed
- 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
- how to record the results of each individual test and the documentation that must be used
- from whom to seek authorisation from if you need to alter or change the test procedures
- how to analyse the test results and make valid decisions about the acceptability of the aircraft
- problems that can occur with the testing activities and how they can be overcome
- the items 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 power transmission systems:
- obtain and use the appropriate documentation (such as job instructions, aircraft power transmission 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 safety procedures
- ensure that isolation procedures are followed and that safe working distance procedures are set up
- carry out the tests, using the specified techniques and procedures
- return all tools and equipment to the correct location on completion of the testing activities
Test two aircraft power transmission systems from the following:
- drive shaft/high speed shaft
- swash plate
- couplings
- intermediate gear box
- tail rotor assembly
- nose gear box
- main gear box
- tail gear box
- accelerometer
- flexi couplings
- drive shaft support
- main rotor assembly
Carry out setting and checking activities, using two from the following:
- dial test indicator
- plumb and bob
- slip gauges
- laser alignment
- clinometers
- go/no-go gauge
- optical site instruments
- using jigs/fixture
Carry out three of the following types of test:
- gear box alignment (main, tail, intermediate)
- main rotor rigging
- drive shaft/high speed shaft alignment
- tail rotor rigging
- ground run
Deal with two of the following complexities during the testing activities:
- equipment with no faults
- equipment with faults
- equipment with intermittent faults
Use two of the following fault finding techniques:
- six point
- input-to-output
- equipment self-diagnostics
- half-split
- function testing
- emergent problem sequence
- unit substitution
- injection and sampling
Review and record fault symptoms and history of problems, using four of the following:
- data sheets
- log cards/history sheet
- calibration records
- aircraft documentation
- maintenance records
- fault records
- other specific recording method
Carry out tests in compliance with one of the following standards:
- Civil Aviation Authority (CAA)/European Aviation Safety Agency (EASA)
- 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 procedures
- specific equipment requirements
- 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