Initial Airworthiness

First of all it should be clear that the definition of "parts and appliances" (Refer to article 3 of the Basic Regulation) includes software. This is software that is installed in an aircraft and used in operating or controlling that aircraft. The rest of this response only refers to this type of software.

Secondly, "Subpart K - Parts and appliances" from Part-21 addressing installation, approval and release is applicable to this software and therefore:

1. this software must be part of the design data; and
2. the installation of this software in a type-certified aircraft is only accepted when it is accompanied by an EASA Form 1 and properly marked; and
3. the installation is approved. (Refer to 21A.303).

In order to achieve 1) and 2), the organisation that manufactures and releases the software must meet the requirements of Subpart F or G from Part-21. This means in particular that the software must be part of the scope of that production organisation and there must be a link between the design organisation and the production organisation.

The conclusion for Field Loadable Software is therefore that this software can be delivered with an EASA Form 1 when:

• it is part of design data for which approval has been applied or granted; and.
• it is produced by, and within the scope of a production organisation that meets the requirements of Subpart F or G.

Marking of this Field Loadable Software must be in accordance with Subpart Q of Part-21. For practical reasons the marking could be on the software "container" (e.g. the CD carrying the software).

The term "critical part" or "critical component" is used in various EASA requirements, certification specifications and also in the EU-US bilateral, however it is not always defined. 
A general definition does not exist. There are currently basically three different definitions:

• for rotorcraft: 
  CS 27-29-VLR.602(a): A critical part is a part, the failure of which could have a catastrophic effect upon the rotorcraft, and for which critical characteristics have been identified which must be controlled to ensure the required level of integrity. 
   
• for engines, propellers and APUs: 
  CS-E.510(c) It is recognised that the probability of Primary Failures of certain single elements cannot be sensibly estimated in numerical terms. If the Failure of such elements is likely to result in Hazardous Engine Effects, reliance must be placed on meeting the prescribed integrity specifications of CS-E 515 (Engine critical parts) in order to support the objective of an Extremely Remote probability of Failure. 
  (similar for CS-P.150(c) and CS-P.160 and also for CS-APU.210(c) and CS-APU.150)
   
• in the EU-US bilateral: 
  A "Critical component" means a part identified as critical by the design approval holder during the product type validation process, or otherwise by the exporting authority. Typically, such components include parts for which a replacement time, inspection interval, or related procedure is specified in the Airworthiness Limitations section or certification maintenance requirements of the manufacturer's maintenance manual or Instructions for Continued Airworthiness. 
   

Each of the above definitions should be used only within their own context and for their own purpose i.e. the definition of the bilateral is only relevant for the automatic acceptance of PMA parts and repair design from the US. Where the term "critical part" is not defined the dictionary meaning of "critical" should be used i.e. crucial, decisive, important, etc. 
For the application of Part 21A.805 critical parts are those identified as such by the design approval holder, which for rotorcraft, engines, propellers and APUs as a minimum should be those using the definitions of the relevant CS.

Article 6 of the Basic Regulation transposes into Community law the International standards of the International Civil Aviation Organisation (ICAO) related to the environmental certification of aeronautical products. The Agency is involved, together with the Commission, in the further development of such standards to ensure that they do take into account Community objectives in this field. Another important task of the Agency is to verify that the design of products comply with environmental requirements. The Agency shall therefore establish and notify the appropriate environmental requirements for each product for which environmental certification is required and issue the appropriate environmental certificates.

Such powers are established by articles 20(d) and (h) respectively of the Basic Regulation and further detailed in Part 21.A.18 "Designation of applicable environmental protection requirements and certification specifications" of Commission Regulation (EC) No 1702/2003.

Because Agency ED Decision 2004/04/CF automatically approves minor changes and major level 2 changes to FAA STCs when made by the STC holder on his own STC, the scope of the EASA STC is considered to be the same as the scope of the original FAA STC. Therefore there is no need for an application and the STC can be applied to all models listed on the FAA STC.

To comply with EASA Part-21, Subpart D, 21.A.109, Subpart E, 21A.118A (b) and Subpart M, 21A.451(a) and (b), it is the obligation of the respective Holders of a Minor Change Approval, a STC, or a Major Repair Design Approval, to specify the required markings, including EPA letters as applicable, in their Design (read, ‘Approved Data’), according EASA Part-21, Subpart Q.

Subpart Q, 21.A.804(a), and related GM, require proper identification of each Part and Appliance that is designed or redesigned, including parts designed to be incorporated in repairs (21A.451), by ‘permanent and legible marking’ hereof, and is applicable for Design Organisations and Manufacturers.

21.A.804(a) 1 and 2  clearly require marking of Parts and Appliances with ‘name, trademark, or symbol identifying the Manufacturer’ and ‘Part number’, as defined in the applicable Design Data.

According to the GM the Design Approval Holder shall identify in all its Design (TC, STC, ETSO, Repair, Change) approved after 28 December 2009, how the Manufacturer has to mark subject Parts and Appliances in accordance with 21A.804(a) 1; which can be limited to identifying a marking field and the method, without prescribing the actual text or symbols.

21.A.804(a) 3 requires additionally marking with the letters ‘EPA’ of all parts produced (manufactured) in accordance with data ‘not belonging to the TC holder of the related product’.

Each interchangeable or removable Part or Appliance that is manufactured in accordance with a design issued by the Design Organisation, shall be permanently and legibly marked according to 21.A.804. The EPA marking was introduced in 2004; this was done to clearly identify any ‘not original’ Part, (which means any Part or Appliance not designed by the TC- or ETSO- Approval Holder), as a trigger for Maintenance Organisations and Accident or Incident investigators, in the light of Continuing Airworthiness. The intention was certainly not to require adding of the letters ‘EPA’ to mark repairs. In this context, EPA marking only applies to the new designed and manufactured parts to be incorporated in the repair. Especially where repairs have an impact on interchangeability, identification of incorporated new Parts is very important, and DO Procedures should address this item.

The only accepted exception with regard to Marking (including EPA), is defined in 21.A.804(b). This subparagraph offers the possibility to not physically mark the Part of Appliance, when it is too small or when marking hereof is otherwise impractical, but only after “Agency agreement”. This wording allows an Applicant/Holder of a Design and the Agency to further define in detail how this ‘agreement’ can be obtained and will be formalised. DOATL should however ensure that the DOA Applicant/Holder reflects this approach in its DO Handbook or Procedures, requiring at least a justification of the reason for not marking physically, and details of the alternative way chosen for the identification, in accordance with 21A.804(b), to know on the authorised release document accompanying the Part or Appliance, or on its container.

Manufacturers of raw materials are not required to hold and cannot obtain a production approval. Only organisations responsible for the manufacturing and subsequent release of a 'product', 'parts’ and ‘non-installed equipment’ as defined in the Basic Regulation Article 3 (3), (4), and (29) are required to hold a POA, if and as specified by Regulation (EU) No 748/2012, and are therefore eligible to apply for such an approval. 

A Part 145 approved organisation can only fabricate parts for its own use in accordance with approved design data (145.A.42(c)). If that data comes from the Type Certificate holder; 21A.804(a)(3) would not be applicable and those parts will not need EPA marking. If the data comes from a Supplemental Type Certificate holder, minor change approval holder or repair approval holder, the parts will have to be marked as prescribed in the applicable data which should include an EPA marking since 28/3/2004.

• 21.A.101 and 21.A.103 require that the changed product meets the applicable certification basis. Therefore the change for which EASA has received an application needs to be demonstrated compliant to the EASA certification basis on product level. It is not sufficient to demonstrate compliance on change level only.
• The change, applied for EASA approval, must include all affected parts of the non-approved change that builds the interface to the EASA approved product and all affected compliance demonstration (influences on the product and the non-approved interface change).
• A limitation is likely to be necessary that the STC cannot be installed on an EASA registered product as long as the interface change is not yet EASA approved.

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The table below indicates in which amendment one particular AMC-20 was published. Follow the link to access the AMC-20 amendments. From amendment 18, all AMC-20 items are included in the latest published AMC-20 amendment.

AMC-20 table

Please also consult the Easy Access Rules for AMC-20.

The ‘demonstration of compliance’ mentioned in point 21.A.95(c) is to be read as the ‘demonstration of compliance’ which the applicant would have performed in case ‘the type certification basis and environmental protection requirements incorporated by references in the TC’ are demonstrated compliant as required by 21.A.95(b)(1).

If a later amendment of the CS is elected as certification basis for the minor change, the demonstration of compliance as per 21.A.95(b)1 still needs to be covered.

This means that an analysis needs to be performed on the differences between the ‘the type certification basis and environmental protection requirements incorporated by references in the TC’ and the later amendment of the CS for the following items:

• Any applicable Special Condition needs to be covered appropriately;
• Any applicable Equivalent Level Of Safety needs to be covered appropriately;
• Any later CS paragraph needs to be applicable to the particular aircraft and compliance demonstration needs to feasible.

Please see FAQ published under Continuing Airworthiness. 

Objective of this FAQ:
This FAQ provides technical guidance on the use of remote ICT to support the issuance of ‘EASA Form 1’ for prototype and new produced parts, appliances and products other than complete aircraft. It is the responsibility of the production organisation to assess whether the use of remote ICT constitutes a suitable alternative to the physical inspection of the part, appliance or product in accordance with the applicable requirements. The production organisation intending to use the remote ICT for those purposes should first discuss its feasibility with the competent authority. 

I.    Terminology:
In the context of this FAQ the following terminology will be used:

• “Issue of an EASA Form 1” means “issue of an EASA Form 1” under Part-21, Subpart G by a certifying staff, “raise an EASA Form 1” under Part-21, Subpart F by an authorised person and “validation of an EASA Form 1” under Part-21, Subpart F by an inspector of the competent authority, except the cases of issuance of an EASA Form 1 for correction of error(s) on a previously issued certificate and for re-certification of an item from “prototype” to “new” provided that the design data has not changed; 
• “Authorised staff” means  “certifying staff” as defined in Part-21, Subpart G, “authorised person” and “competent authority inspector” as defined in Part-21, Subpart F; 
• “Item” means any part, appliance or product other than a complete aircraft;
• "Applicable design data" means "non-approved design data” in case of prototype and “approved design data” in case of new produced item; 
• “Task” means any inspection, test and/or verification, as described in a written procedure, needed to be performed by an authorised staff before signing an EASA Form 1; 
• “Remote ICT” means any real-time video and audio communication tools using information and communication technologies (ICT), which aim at enabling performance of the tasks by the authorised staff from a location different than where is located the item (on-site).

II.    Regulatory context:
According to:

• point 21.A.130(a), the  holder of a letter of agreement issued in accordance with Part 21, Subpart F;
• point 21.A.130(d), the competent authority in the context of Part-21, Subpart F; and 
• point 21.A.163(c), the holder of a production organisation approval (POA) in accordance with Part 21, Subpart G 

may issue an EASA Form 1 for produced items in order to certify their conformity to the applicable design data and, in case of new items, their condition for safe operation. 

The EASA Form 1 has to be issued by appropriately qualified authorised staff.
Part 21 does not require that the authorised staff has to be on-site when issuing the EASA Form 1, nor how the production organisation and the competent authority shall determine whether the part/appliance/product other than aircraft conforms to the applicable design data and, in case of a new item, is in condition for safe operation. These should be detailed in a written procedure accepted by the competent authority.

Part 21 requires:

• in point 21.A.130 (d) that the competent authority validates the EASA Form 1 after inspections performed in according to 21.B.135(b), “if it finds after inspection that the product, part or appliance conforms to the applicable design data and is in condition for safe operation”; and
   
• in point 21.A.165(c) that the POA holder has to:

  2. “determine that other products, parts or appliances are complete and conform to the approved design data and are in a condition for safe operation before issuing an EASA Form 1…”

  4. “determine that other products, parts or appliances conform to the applicable data before issuing an EASA Form 1…”.

Typically compliance with these requirements is ensured through on-site presence of the authorised staff in order to guarantee appropriate access to the item, as needed.

However, compliance with these requirements may be also ensured in certain circumstances, determined as per the considerations described in chapter III, by remotely conducting the tasks which are needed before issuance of an EASA Form 1 by the use of remote ICT. The following considerations should be used as a guideline when the on-site presence of the authorised staff is to be replaced by virtual presence, using remote ICT. 

III.    Use of remote ICT to support the issuance of EASA Form 1
Remote ICT may have limitations that could render it unsuitable for some applications. Accordingly, careful consideration and risk management should be applied when making a determination when to use it. These considerations, listed below, are however not exhaustive and should not be treated as a checklist. 

1.    General considerations

• As an overarching principle, it needs to be determined whether the nature of the tasks to be performed by the authorised staff allows the use of remote ICT;  
• the facility where the item is located:
• a)    should be referred to in the EASA Form 65 or EASA Form 55, directly or indirectly by reference to the corresponding section of the manual or production organisation exposition, or
• b)    in case of a POA, should be a facility from where a production organisation exposition’s procedure related to point 21.A.139(b)1(xv) authorises the issuance of the EASA Form 1;
• The complexity, novelty, and safety criticality of the item to be released with the EASA Form 1, should be taken into account; 
• The level of competence and experience of the personnel in the use of the particular procedures and equipment that will be used to conduct the tasks before issuing the EASA Form 1; 
• Previous experience of the organisation / confidence in the organisation’s Inspection system / Quality system / Management system; and
• The appropriateness of the inspection and test instruments and/or equipment, especially if used to evaluate qualitative aspects of a product, part or appliance.

2.    Equipment and Setup Considerations

• The suitability of video resolution, fidelity and field of view for the task being conducted;
• The need for multiple cameras, imaging systems or microphones and whether the person performing or witnessing the tasks can switch between them or direct them to be switched and has the possibility to stop the process, ask a question, move equipment, etc.;
• The controllability of viewing direction, zoom and lighting;
• The appropriateness of audio fidelity for the evaluation being conducted;
• Whether real-time, uninterrupted communication between the person(s) authorised to remotely witness the activity (authorised staff) and the personnel conducting it exists at the location where the item is located;
• The need for unique testing devices or equipment (for examples, fast-frame cameras, special lighting conditions, sensitive listening devices, mobile phones with cameras for HD video calls);
• Whether personnel have been adequately trained in the proper set up, validation and use of the technology, tools and/or equipment to be used; and
• The need for recording the audio and video data, as well for retention of them or other information.

3.    Cybersecurity considerations

There are cases where the facilities, where the tasks has to be performed, are subject to strict security limitations. When using remote ICT for the tasks needed before issuing an EASA Form 1, it is the responsibility of the organisation to provide an equivalent level of security, thus the IT security responsible person within the organisation should concur to the ICT technology before proceeding.

4.    Documenting the use of remote ICT

The documented processes (procedures) developed by the holder of a letter of agreement or a POA should be accepted by the competent authority and describe:

• The risk assessment process needed to determine the appropriateness of the remote ICT taking into account the above mentioned considerations;
• The tasks to be performed, including preparation activities, inspections, tests, verifications to be done, personnel involved in the remote ICT activity and their level of competence; 
• How authorised staff access to all necessary data (e.g. drawings, schematics, datasheets, etc.) needed to determine that the item conforms to the applicable design data, needs to be guaranteed; 
• How remote ICT will be used in real-time (not pre-recorded) so that the authorised staff may direct the performance of the tasks as if conducted in-person, on-premises, with the aid of the equipment or the personnel supporting the activity at the remote location;
• Procedures for conducting a re-inspection if the equipment malfunctions or the process fails to yield acceptable results. A re-inspection using remote ICT may be accomplished after correcting the malfunction or process, or by an actual on-site inspection;
• How the authorised staff should record and communicate any difficulties or concerns regarding the process so that the organisation can improve its programme;
• How use of remote ICT will be documented in the required records; and
• How IT security is maintained throughout the remote ICT process (data protection and intellectual property of the organisations also need to be safeguarded).
   

See answer in FAQ n.127777 (Additional Airworthiness specifications)