When an error occurs the conditions present at that time are known as ‘Local Factors’. In aircraft engineering the main areas of concern has to do with documentation, tool control, fatigue and time pressures.
The largest number of incidents reported to the Civil Aviation Authority (CAA) has to do with documentation errors, most of which is falsification and forgery. The falsification of documentation generally arises from one of the ‘Dirty Dozen’ devised by Gordon Dupont, that of Complacency. With complacency an engineer may well fail to carry out a task due to the fact that, said task never reveals a fault or is deemed superfluous, therefore, the task is signed off as completed without it being carried out. Another contributing factor for this falsification could be the time pressure for turning the aircraft around so the engineer may well ‘cut corners’ in their servicing to meet the schedule, thinking they are doing the right thing for the company.
A more severe form is when the falsification and forgery pertains to serviceability of components and hence the EASA Form1 documentation. This is where parts not of the correct standard are sold as aircraft worthy, for instance a man ‘pleaded guilty to several charges surrounding issuing false airworthiness certificates intended for wheel and brake assemblies for large passenger and cargo airplanes.’ (Orlando Sentinal, 1996)
On the low end of the documentation error scale, mistakes could occur due to complex language, inaccurate translations and manual layouts. Or the company’s paper work being complex with an overabundance of cross referencing, form raising and poor hand writing. All of which can lead to missing tasks or misinterpretation of a particular task.
Tool control and housekeeping are major factors for aircraft due to the phenomenon known as FOD (Foreign Object Debris/damage). Having witnessed an incident where a helicopter suffered power loss on take-off due to a cloth rag covering the engine intake after being blown over the guards from the down wash, which resulted in the airframe dropping back down onto the pan. It is, therefore, easy to comprehend the necessity for good housekeeping by ensuring a high standard of engineering hygiene and thus reduce the incidents caused by FOD. Tool control comes into the FOD category by the name of loose articles, whereby tools are left on the aircraft by mistake or they fall into a hard to reach place. As the aircraft travels the vibration could cause the tool to migrate from its location to a place where damage to, or jamming of components can occur, causing a catastrophic occurrence. Refer to AAIB bulletin 10/2003 for screw driver jamming flight controls (CAA AAIB, 2003).
Due to the nature of the industry most servicing’s are carried out at night. This introduces the requirement for shift work and brings in a whole new problem caused by the circadian rhythm which naturally occurs within a person. Long hours, switching sleep patterns and working under stress, can and does cause fatigue. However, due to the individuality of people, what they can endure and are comfortable with, means fatigue is rather fluid and affects people at different times, with various symptoms. ‘It is insidious, and the person fails to realize just how much their judgment is impaired until it’s too late.’ (Dupont, 1993) In fact Dupont also states that it is the number one contributing factor for human error.
Aviation is a customer driven industry, it is therefore, imperative to have timings for passengers to know where and when they are required to be for their flight. This aids in organising connections for a smooth, stress free travel experience, which hopefully, will bring a return in custom. However, due to the technical nature of the aircraft and for flight safety, servicing is mandatory. Aircraft do not make money on the ground, hence the faster the aircraft can be turned around fit to fly, the less financial impact there is. Furthermore, due to the technical complexity of aircraft systems faults can, and do occur during flight. This means the engineer is required to assess the fault and rectify it, if required, so the aircraft can finish the scheduled trip without undue delay to the passengers.
It can be seen then that time pressure is a large issue for the maintenance staff and flight crews. This increases stress and with excessive amounts of stress there is a greater risk of an error occurring, this is also part of the ‘Dirty Dozen’ (Dupont, 1993)
Eradication is impossible when dealing with human error; therefore, measures need to be in place to help reduce them.
The company’s documentation should be straight forward with simple phraseology to aid in understanding thus reducing ambiguity. Cross referencing to various job cards and work packs should be reduced to a minimum and writing must be legible to everyone. Avoid joined up writing and print the words, however, keeping the upper and lower case lettering aids in the speed of the reader.
As for the serious breaches, then education and the individuals integrity is the only defence. If an individual is determined to circumvent the procedures, then punitive action is required. If the falsification of paper work is due to complacency, further training could be the initial phase. If the action continues disciplinary action may well have to be considered. The more serious breach of form1 forgeries then prosecution of the individual may be the only recourse
The aircraft engineer is accountable for their own tools. There are many ways to monitor tools, from the simple shadow board method which gives an easy visual reference when something is missing. To microchip technology, which registers the tool removed, when it was removed and by whom. Some companies are tending towards the military system of banning personal tools and having company tool boxes which have to be signed out and back in to stores, where they are checked.
As fatigue has symptoms, the individual has to be aware of them in themselves and others. These include short term memory loss, loss of concentration, irritability and depression to name a few (NHS , 2013). Before fatigue can take hold the individual should take a break, or speak to the company to reduce work load before it becomes a medical condition where time off work would be inevitable.
Time pressure is more to do with perspective. If the individual perceives they do not have enough time, performance will be reduced, stress will increase and errors made (Case Western Reserve University, 2009). Focus on the task at hand and have confidence. (Case Western Reserve University, 2009). Evaluate the requirements and ask for help if required and if being harassed to complete the job then the management need to be told to refrain from adding pressure politely.
Design Organisation Approval and Design Assurance System’s organisational structure in control and supervision.
To gain design organisation approval the application will go through the Certification Directorate of EASA. The organisation would have to submit a Design Organisation Handbook, which will show the organisation’s compliance with EASA Part 21 Sub part J, this mainly covers the company’s Maintenance Organisation Exposition known as the MOE. Within this document positions and assets will have to be established. These include:
A responsible person for handbook administration and contact details of that person, along with the amendment procedures which will need to be listed. The company’s resources, terms of approval known as their scope, a file of all changes to the handbook including the referenced documents, which can be stored electronically. The Presentation of design for the organisation also has to be included. This section should give general information about the organisation’s structure, staff numbers, premises, and history. Furthermore, it should state the scope of the organisation’s undertakings at the various premises it operates from. Therefore, a list of the Design Organisation’s facilities, along with their supplier lists will be required.
There should be organisation charts showing the position of the Design Organisation within the company and the chains of responsibility of nominated design staff. A Human Resources section listing the staff positions, responsibilities and qualification criteria will have to be present to give structure. Therefore, a Design Engineer will be required with their qualifications, responsibilities and tasks will have to be listed along with the training criteria for that post. This also applies to Compliance Verification Engineers who shall be listed by name and demonstrate adequate professional experience. Managerial staff will have to be listed which comprises of the: Chief Executive, Head of Design Organisation (HDO), Head of Office of Airworthiness (HOA) and Head of Independent System Monitoring (HISM). The Head of Airworthiness and Head of Independent System Monitoring report to the Head of Design, who in turn reports to the Chief Executive. The HISM basically audits the company’s activities, but only those they are not directly involved with.
The next section contains the authorised signatories list along with the documents the respective personnel are authorised to sign. It will give their names and positions within the company. There will also be an Independent System Monitoring position where they perform surveillance audits of the design suppliers. The Scope of the ISM is ensured by the independent auditing and reporting system to monitor the compliance and effectiveness of the Design Organisation. (EASA, 2013)
As can be seen there is a substantial amount of structuring required for a Design Organisation. When the organisation develops a new component or system, it has to be designed in a manner that allows it to be fitted to the appropriate aircraft, then a
number of prototypes will be built and tested. Once the testing has been completed a Compliance Demonstration Report has to be filled out to show the new system is, in fact, compatible for the aircraft type it is intended for. The supervision for this comes from the design engineers, once they are happy with the results it will go to the compliance verification engineers. These engineers test to verify the compatibility of the new system with the existing systems of the aircraft type. Moreover, the system actually fulfils the remit for the functions it is supposed to perform to the required standards laid down by the design parameters which were agreed to for the client.
The Airworthiness department crosses over with the verification engineers and in some organisations the verification engineer is a part of this section of the company. Their job not only entails the functionality of the component but all the materials, manufacturing processes and the overall finished article complies with the airworthiness criteria. This has to take into account that of software compatibility, criticality levels, electromagnetic compatibility with fully operational aircraft systems and the consequential surrounding interference, along with redundancy levels for failures when dealing with new electronic and computer programmed devices.
The Head of Independent System Monitoring concerns itself with quality assurance of the product. This ensures that the product is up to standard, not only for the company, but also for the Aviation Authorities requirements and for the customer. The quality assurance department has to work independently from the other engineering departments but hold the same authority status as the heads of Design Engineering. Furthermore, this department, as stated previously has direct access to the Chief Executive for instant authorisation to implement changes with relation to training, quality and safe working practice (Air Service Training, 2013). Part of this department is Independent system Monitoring section, whereby previously stated they audit the suppliers. This means it is their job to monitor the manufacturing processes and the grade of the raw materials used for production of the components required to build the system that their company has designed. This, therefore, ensures that each step of the process for the building of the system and all its sub-parts will adhere to the standards laid down by the Aviation Authorities and EASA. This in turn should aid in guaranteeing the compliance of the system and parts thereof for certification, along with the appropriate documentation and evidence will then allow it to be released into service for use.
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