NDT.net - September 1998, Vol.3 No.9
Table of Contents ECNDT '98
Qualification and Certification of Inspection Personnel in the European Aerospace Industry
R. Henrich, G. Tober*
|*Corresponding Author Contact:|
Daimler Benz Aerospace Airbus Dep. EVP (Measurement & Testing, Center of Structure Technology & Tests) D-28183 Bremen , Germany ; email@example.com
Tel.: +49.(0)421.538-4795; Fax.: +49.(0)421.538-3760
Important items of PrEN 4179 are explained and deviations from other standards are discussed.
The aim is to make it clear that the employer-based certification/approval system used in the aerospace industry worldwide provides advantages for employers as opposed to a centralized certification system.
The standard pr EN4179 avoids superfluous formalism. It is therefore more flexible in use and strongly focuses on the actual requirements of the aerospace industry employer.
The employer, and especially the prime contractor, holds the responsibility for the certification process. The existing certification systems in the aerospace industry can be largely adopted, and, due to the harmonization with MIL and SNT TC-1A, there are advantages for a cooperation with the American market and the international market in general.
In the aerospace industry, there is the clear global requirement that the qualification and certification of personnel for NDT inspections shall be carried out in compliance with specific approved rules.
There are numerous national and international standards with reference to this topic, and often companies are facing difficulty with complying with the various customer requirements.
This is a common fact, and in the fall of 1992, the European standard EN 473 which concerns the qualification and certification of NDT personnel came into effect.
Today, the standard EN 473 is applied by an increasing number of companies, but the majority of European aerospace companies still refuse to use it.
The main argument for this refusal is that it would require a great amount of additional formalities and costs without gain of additional safety. The well-proven employer certification system that is applied all over the world is replaced by a centralized certification system that requires lots of formalities.
The second important argument named in this context against a certification system that is independent from the employer is that, in the aerospace industry, high safety requirements in connection with the necessity to reduce weight wherever possible require new materials and manufacturing processes to be introduced more frequently than in many other industrial branches.
As a consequence of this, the requirements for existing and new NDT procedures and also the qualification of the inspection personnel keep becoming stricter. Often, new NDT procedures must be developed, qualified and introduced very quickly and, naturally the correspondingly qualified personnel must be available, too.
In this situation, the responsible Level 3 individual must be able to react flexibly with respect to the training and certification of his NDT personnel. Only he knows what qualification will be required from his inspection personnel, and only he knows all the problems arising on the job to enable him to decide if an external training will suffice or if in-house training will be necessary to fulfill the respective requirements. In case of incidents/accidents, the employer must prove that his inspection personnel was trained in compliance with the safety requirements of the respective product; it will not be possible to refer to a centralized certifying body.
Practically all NDT laboratories of the European aerospace industry which are in some fashion concerned with products for American companies or airlines are solely inspected for compliance with the MIL STD 410 requirements during audits performed by the customers, licensees or the FAA.
In other words, the European aerospace industry will not be able to avoid the requirements of MIL STD 410 E so easily, anyway.
In many cases, level 3 inspectors must undergo specific training or tests for employment in foreign countries, or German suppliers are submitted to audits per MIL or SNT on their own premises.
All these items were the reasons why AECMA C 5 decided about 5 years ago to establish an ad-hoc working group for the preparation of its own standard. It was the aim to prepare a standard with employer certification and, in this connection, to try to achieve an extensive harmonization with MIL-STD-410 due to the close cooperation with the US market; however, this was not necessarily meant to exclude the consideration of special European conditions or general improvements. Another aim was, of course, to define a qualification and certification system ensuring optimum safety, but not resulting in unnecessary costs.
At this point, it should be mentioned that the JAR-145 Appendix 7 has already adopted the prEN 4179 as the basis for the qualification of non destructive Inspection Staff.
In the following, the new aerospace standard pr EN4179 for the field of qualification and certification of NDT personnel will be presented in brief with respect to differences from MIL-STD 410E and EN473:
EN 4179 in Comparison with MIL-STD 410 E
It ws already pointed out that the EN 4179 and the MIL-STD 410 E standards are largely compliant. Still, there are a few items where slight deviations or additional alternative procedures, respectively, of the EN 4179 are possible with respect to the MIL; these are listed in the following.
If the EN 4179 is complied with, the requirements of the MIL will also be fulfilled, or there is a possibility of implementing the EN 4179 in such a way that all MIL requirements are fully complied with.
- Cancellation of specific definitions in the EN4179 that are related to the contracting of companies by the ministry of defense
- EN 4179 has the title "Qualification" and "Approval" of NDT Personnel, the MIL title is "Qualification and Certification"
- in the EN 4179, a "National Aerospace NDT Committee" can be instituted to prepare guidelines and aids for the implementation of the standard (course outlines, examination questions, examination procedures, auditing of training facilities, etc.)
- aside from the 3 qualification levels for the certification, the EN 4179 allows for a further subdivision into levels 1 and 2 for limited activities (see item 6.3)
- higher minimum training periods for dye penetration and magnetic particle inspections in EN4179
- the EN4179 defines the importance of grading general, specific and practical qualification examination in such a way that, for lower levels, the practical part of the examination will be more important, whereas, for higher levels, the theoretical part will be more important.
The utilise equal grade weightings as prescribed by the MIL, however, can be applied alternatively if such is requested by the customer.
- alternatively to the re-examination to be passed every 3 years for level 1 and 2 employees, in EN 4179 an annual theoretical and practical evaluation by level 3 inspectors is possible on the job
- a more detailed definition of the level 3 re-examination can be found in EN 4179
- EN 4179 provides for a credit system as an alternative for the re-examination to be passed every 5 years for level 3 individuals
- Requirements for training facilities (outside agencies) are defined in EN 4179
EN 4179 in Comparison with EN 473
The centralized certification via an "independent certifying body" (ICB) and, if applicable, "authorized body" for specific branches of the industry is the center piece of the EN 473.
This ICB is responsible for all formal issues of the qualification and certification of levels 1, 2, and 3 inspectors. The employer confirms such information as school education, training, and experience of his personnel towards these bodies, but is himself no longer involved in the certification procedure.
In MIL, SNT, EN 4179, these formal tasks are fully within the responsibility of the employer or his level 3 employee in charge.
- minimum training hours for level 2, except for eddy current inspection, are considerably higher, for X-ray and ultrasonic testing, they are twice as high as in EN 4179/MIL
- in EN 473, only such procedures can be adopted, aside from the 5 basic procedures and the leakage test, for which national certification programs are in existence.
- the EN 473 requirement for direct access to the level 3 examination is (independently from the previous training) the practical level 2 examination; the EN 4179/MIL requires "equivalent experience" for engineers
- in the EN 473 level 3 examination, the candidates must also demonstrate - apart from knowledge on the procedure itself - level 2 knowledge for 3 more methods of which the X-ray or ultrasonic procedure must be one
EN 4179 also requires knowledge on other procedures, but only to this methods which are applied by the respective employer
- in the EN473, renewal examinations are required only every 10 years for level 1,2 and 3 inspectors whereas, in the EN 4179, the interval is every 3 years for level 1 and 2 with the alternative of an annual practical and theoretical evaluation on the job and every 5 years for level 3.
Some Important prEN 4179 Definitions
"A written statement by an employer that an individual has met the applicable requirements of this standard".
In the EN 4179 draft, the word "certification" is deliberately avoided, and the word "approval" is used instead which includes not only the verification procedure for qualification but also the employer's authorization of the inspector.
- Prime contractor
"The organization responsible for the manufacture and/or maintenance of aerospace products".
"An organization responsible to the prime contractor for the manufacture or maintenance of aerospace products".
- Written practice
"Procedures that describe the control and administration of NDT personnel qualification and approval".
The prEN 4179 specifies a "written practice" for all companies involved in any form of NDT methods where a subcontractor can work according to the written practice of the prime contractor or according to his own which shall be approved by the prime contractor.
With this wording, the prEN 4179 highlights the special responsibility of the prime contractor with respect to the meaning of the word employer.
- National aerospace NDT board
"Independent aerospace organization made up of representatives from the aerospace industry"
Such a board is not definitely specified in the standard; however, the standard states specific tasks of the board where it exists, such as:
- to implement the procedure for the qualification and certification of NDT personnel per requirements of the 4179 or provide support for this process
- to recognize equivalencies of qualification and approval in conjunction with the employer
- to prepare general guidelines within the meaning of the prEN 4179, regarding:
requirements for NDT training facilities/outside agencies, course outlines, examination questions and examination procedures
By establishing such a board, however, the aerospace companies are given the opportunity to cooperate and save costs on auditing and approval of outside agencies and subcontractors.
Such boards have existed in France (COSAC) for quite some time, in Germany (BDLI Lenkungsausschuá fr ZfP Personalqualifikation) for several years.
- Specific examination
"The written examination to determine an individual's understanding of written instructions, codes, standards, product-specific technology and specifications for given inspection methods used by the employer".
- Practical examination
"The examination used to demonstrate an individual's ability in conducting the NDT methods that will be performed for the employer".
These definitions are to ensure that the qualification is strictly oriented towards the actual requirements of the respective employer. They exceed by far the requirements of the EN 473 for sector-specific training.
- Common Methods
Precise requirements with regard to training, experience and examination are only defined for the basic methods:
- liquid penetrant (PT)
- magnetic particle (MT)
- eddy current (ET)
- ultrasonic (UT)
- radiography (RT)
For any other method, such as leakage test, thermography, computer tomography, etc. the standard may be applied in the same manner. The corresponding requirements have to be defined by the employer's responsible level 3 inspector in accordance with the guidelines for the basic methods.
EN 4179 permits a flexible extension of its application if this is required due to new methods and safety requirements at the employer's.
- Levels of Qualification
PrEN 4179 defines the requirements for qualification of the basic levels 1, 2 and 3.
Further subdivisions are possible which must be described in detail by the employer in the written practice. This rule has been incorporated to be able to reduce the qualification effort for strictly limited activities.
One example of this is the inspection of electrical conductivity by means of the eddy current method. Although this is a very important inspection method, especially for airframe manufacturing, it is not necessary to stipulate a complete training for eddy current testing, "ET 1 restricted to conductivity measuring" is sufficient and requires the correspondingly smaller qualification and examination effort.
For personnel working with automated testing equipment (e.g. eddy current wheel rim testing apparatus) performing strictly limited tasks, there is the possibility to achieve the corresponding specific reduced qualifications for approval.
- Minimum training hours
The minimum requirements according to EN 4179 correspond to those of the MIL with two exceptions (MT and PT) where there are slightly higher demands in prEN 4179; they are, however, still below the requirements of the EN 473. The latter is due to the fact that, within the aerospace industry, there is the possibility to provide very specific training in accordance with the actual requirements of the aerospace companies at the industry's own training facilities or at the employer's, so that the time available for training can be used effectively and the required periods can be reduced in comparison with multi-sector training.
The important aspect of recertification is the re-examination which shall therefore be dealt with in detail here.
According to the EN 4179 draft, level 1 and 2 inspection personnel must take a re-examination every 3 years and level 3 personnel every 5 years. The scope of the examination complies with the practical and specific part of the initial certification; an examination with regard to the general part depends on the employer's level 3 individual responsible for the certification of inspection personnel.
As an alternative to re-examination, level 1 and 2 personnel can be subjected to an "annual practical and theoretical evaluation" on the job, the requirements of which are defined in the standard and which must be documented in a checklist; if the candidate remains below 80 %, he must take the re-examination.
A structured credit system can be optionally applied for level 3 personnel.
Present Status of the Standard
Currently, the NPS-examination (check for correct spelling and wording in three languages) is performed, after that, the standard will be submitted for CEN agreement. We are expecting the white paper to be released by the end of 1998.
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