Aircraft Certification Standards and Airworthiness Compliance

Posted on Jan 26, 2025 in Architecture

Means of Compliance (MoC)

MoC 0, Statement: Direct Answer. Applicant declaration, normally supported with a short rationale, which shows compliance with the requirement.
MoC 1, Description: Descriptive document or reference to a document including the drawings that show compliance with the requirement.
MoC 2, Analysis: Documents with calculations and analysis that show compliance with the requirements.
MoC 3, Safety Assessment: Specific analysis prepared to show compliance with Safety Requirements (1309).
MoC 4, Laboratory Tests: Tests performed in rigs, benches, or laboratories.
MoC 5, Ground Tests: Tests performed in an aircraft representative of the aircraft design on the ground.
MoC 6, Flight Tests: Tests performed in an aircraft representative of the aircraft design in-flight and performed by a flight test crew.
MoC 7, Inspection: Visual Inspection of the real aircraft to verify compliance with the requirements that cannot be determined from the evaluation of technical data.
MoC 8, Simulation: Test performed using a tool that represents and simulates representatively the aircraft behavior.
MoC 9, Equipment Qualification: Documentation prepared by the equipment supplier and endorsed by the applicant in which the equipment relevant qualification data is presented. Normally is the Equipment TSO or DDP.

EASA Certification Panels

Panel 0: Project Certification Manager (Initial Certification & Continued Airworthiness)
Panel 1: Flight, Handling Qualities, Human Factors, AFM
Panel 2: Flight Crew Data
Panel 3: Structure, Loads
Panel 4: Hydromechanical
Panel 5: Electrics
Panel 6: Avionics
Panel 7: Powerplant, Fuel
Panel 8a: Cabin Safety
Panel 8b: Environmental Control System/Icing
Panel 9: Noise and Emissions
Panel 10: Software and Complex Electronic Hardware
Panel 11: Cabin Crew Data
Panel 12: Safety
Panel 14: ICA
Panel 15: MMEL
Panel 16: Simulator Data

Aircraft Certification Specifications (CS)

CS-22: Sailplanes and Powered Sailplanes
CS-23: Normal, Utility, Acrobatic, and Commuter (MTOW<19000Lb & pax 19)
CS-25: Large Aeroplanes (MTOW >19000 Lb pax >19)
CS-26: Airworthiness Specifications for Operations
CS-27: Small Rotorcraft (MTOW < 7000 Lb & pax 9)
CS-29: Large Rotorcraft
CS-31 GB: Gas Balloons
CS-31 TGB: Tethered Gas Balloons
CS-31 HB: Hot Air Balloons
CS-34: Aircraft Engine Emissions and Fuel Venting
CS-36: Aircraft Noise
CS-APU: Auxiliary Power Units
CS-AWO: All-Weather Operations
CS-E: Engines
CS-ETSO: European Technical Standard Orders
CS-LSA: Light Sport Aeroplanes
CS-P: Propellers
CS-SIMD: Simulator Data
CS-STAN: Standard Changes and Standard Repairs
CS-VLA: Very Light Aeroplanes
CS-VLR: Very Light Rotorcraft
CS-MMEL: Master Minimum Equipment List
CS-GEN-MMEL: Generic Master Minimum Equipment List
CS-CCD: Cabin Crew Data
CS-FCD: Flight Crew Data
CS-CO2: Aeroplane CO2 Emissions
AMC-20: General Acceptable Means of Compliance for Airworthiness of Products, Parts, and Appliances

Structure of Aircraft Airworthiness Standards (CS)

Book 1: Mandatory Requirements

Subpart A, General: Provides information about the types and category of aircraft to which the standard is applicable.
Subpart B, Flight: Establishes the requirements for Performances, Handling Qualities, Flying Aspects.
Subpart C, Structures: Ground and flight loads, airframes, control system, landing gear.
Subpart D, Design and Construction: Deals with design technique, materials, structural tests.
Subpart E, Power Plant: Requirements for Power Plant installations and associated systems: Fuel, oil.
Subpart F, Equipment: Establishes requirement for different general systems and equipment.
Subpart G, Operating Limitations and Information: Provides requirements for all the information that must be available to the flight crew.
Subpart H, Electrical Wiring Interconnection Systems: Defines requirements for any wire, wiring device, or combination of these, including termination devices, installed in any area of the aeroplane for the purpose of transmitting electrical energy, including data and signals between two or more intended termination points.
Subpart J, APU: Establishes the certification requirements for the Auxiliary Power Unit.

Book 2: Accepted Means of Compliance (AMC)

Includes the Accepted Means of Compliance for the corresponding CS (AMC). It does not constitute mandatory requirements, but a method accepted for the authority (EASA), to demonstrate compliance against the requirements (paragraphs). Although they are not requirements, it is highly recommended to follow the AMCs.

Key Documents and Lists

AFM (Aircraft Flight Manual): Must include Operating limitations, Operating procedures, Performance information.
MMEL (Master Minimum Equipment List): A list, prepared by TC holder and approved by the EASA (or Type Certification Authority), appropriate to an aircraft type, that determines those instruments, equipment, or functions that may be temporarily inoperative, associated with special operating conditions, limitations or procedures, as applicable, for a specific aircraft type or model. All system related to the airworthiness not included in the MMEL, are automatically required to be operative.
MEL (Master Equipment List): List which provides, under specified conditions, which particular instruments, equipment or functions may be inoperative at the commencement of a flight. Is prepared by the operator, and approved by the competent National Authority. Cannot be less restrictive than the approved MMEL.
ICA (Instructions for Continued Airworthiness): Constitute maintenance documentation (or data module) that are required to show compliance with CS 25.1529 and appendix H, CS 25 Subpart H.
ALS (Airworthiness Limitations Section): of the instructions for Continued Airworthiness contains airworthiness limitations and airworthiness maintenance requirements, i.e. those ICAs which set forth: mandatory replacement time, mandatory life limits, inspection interval and related inspection procedure, maintenance requirements and safety requirements required to show compliance to specific CS 25 requirements.
Safe Life ALIs, Systems Life Limited Equipment- SEMR, Fuel Airworthiness limitations, EWIS Maintenance Requirements

Design Assurance System

The Design Assurance System consists of: the organisational structure, the allocated responsibilities, the documented processes and methods, the resources. The Design Assurance means all those planned and systematic actions necessary to provide adequate confidence that the organisation has the capability: To design products and parts in accordance with the applicable AW, To show and verify the compliance, and to monitor it. Composed by: Head of Design Organisation, Office of Airworthiness, Compliance Verification Engineers, Quality Assurance System.

Handbook

It must contain: tasks which can be performed under the approval, organisation, its main departments, line management and of a functional relationship, assigned responsibilities and delegated authority, way in which the organisation performs all the design functions in relation to airworthiness and environmental protection approvals, recording systems, monitoring systems, names of the signatories.

Right People in Right Places

Obligations

Provide EASA with information or instructions related to required mandatory actions.
Provide EASA with Statements of Compliance for the Type Design.
Maintain the DOM up to date.

Privileges

An Approved Design Organisation is authorised to perform certification and airworthiness activities on behalf of EASA.
Issuance of certification documents [in the frame of type certification and approval of major changes] without further EASA verification.
Classification of changes as minor or major.
Approval of minor changes.
Approval of some Major Changes (new privilege).
To Issue Certain STCs or Major Changes to STCs.
Approval of Repairs.
Approval of Flight Conditions and Flight Permits.

Part 21

Section A: Requirements for Applicants, Rights and Obligations

Subpart A: Provisions
Subpart B: Type Certificates and Restricted Type Certificates
Subpart D: Changes to Type Certificates
Subpart E: Supplemental Type Certificates
Subpart F: Production without Production Organisation Approval
Subpart G: Production Organisation Approval
Subpart H: Certificates of Airworthiness and Restricted Certificates of Airworthiness
Subpart I: Noise Certificates (Deals with procedures to obtain Noise certification)
Subpart J: Design Organisation Approval (DOA)
Subpart K: Parts and Appliances
Subpart M: Repairs
Subpart O: European Technical Standard Order
Subpart P: Permits to Fly
Subpart Q: Identification of Products, Parts and Appliances (It regulates the appropriate identification of products, parts and appliances including Manufacturer Name, product designation, Serial Number, and any other marking required by the Agency, with special requirements for critical parts and ETSO parts)

Section B: Procedures for Authorities

Certificate of Airworthiness (Standard): Identifies technically an individual aircraft, define its characteristics and allow its operational usage. To issue the CoA it is needed: Copy of the Type Certificate covering the aircraft, Certificate of Conformity of the aircraft, Documentation identifying the aircraft, AFM, W&B Manual, Maintenance Plan and Program and IPC, List of in force ADs applicable embodied and pending.
Provisional Certificate of Airworthiness: Those aircraft that during its certification process, enough knowledge of their characteristics has been obtained, in order to impose airworthiness limitations for which the aircraft is considered Safe for Flight.
Experimental Certificate of Airworthiness (CAE): Those aircraft used for Development or Certification Flight Tests or Experimental Usage.
Restricted Certificate of Airworthiness: Those aircraft covered by a Type Certificate, but whose airworthiness is not fully assured, but is able to perform a safe flight and landing with the necessary limitations. Usual CofA to cover Production, Industrial Flights and sometimes acceptance flights with the customer.
Export Certificate of Airworthiness: Document issued for an Aircraft that will be exported from Spain. Type Certificate covering the Design is also needed.
Permits to Fly: It is an special Certificate of Airworthiness. issued when a certificate of airworthiness: is temporarily invalid, or when a certificate of airworthiness cannot be issued for instance when the aircraft does not comply with the essential requirements for airworthiness or when compliance with those requirements has not yet been shown, but the aircraft is nevertheless capable of performing a safe flight.

Phases of Certification

Phase 0, Feasibility Study: Application (Shall be made in a form and manner established by the Agency. Shall be accompanied by a three-view drawing of the aircraft and preliminary basic data, including the proposed operating characteristics and limitations. Shall include the application for approval of operational suitability data. EASA confirms the receipt of the application and assigns a project number. If accepted EASA issues a letter of acceptance with the allocation information.)

Phase 1, Application and Project Organisation: EASA letter of acceptance allocates the project to a Project Certification Manager (PCM). EASA specialists are organized in panels. A meeting involving all the EASA panels affected by the modification. Establishment of the initial certification basis (Proposed by the applicant. Included in the first issue of the Certification Plan.)

Phase 2, Familiarisation & Certification Basis: Establishment of the initial certification basis. The applicable certification specifications in effect at the date of the application. Analysis of environmental protection requirements. * Certification Review Items (CRIs). Formalize a discussion between EASA and the applicant. Authorities familiarisation with Design, Requirements negotiation, Anticipate Certification impact on A/C design, Start internal activities on Certification Plans

Phase 3, Compliance Demonstration: Define and Freeze the Type Design, Release Compliance Documents, Release Certification Summaries, Release Compliance Statement. *Certification Action Items (CAIs). Records EASA team Panel involvement in the showing of compliance phase of the certification process Level of involvement (LoI) The compliance demonstration activities and data that Authority retains for verification during the certification process, and the depth of these verifications. Compliance Data is grouped in CDIs (Compliance Demonstration Items)

Phase 4, Release of Type Certification – EASA: Closure of actions. The applicant shall provide a Declaration of Compliance stating the type of design complies with the Certification Basis.

Change to the Type Certificate

Any design change of an already approved Type Certificate is made by means of changes to the Type Certificate. An embodiment of any change not approved renders the Certificate of Airworthiness* (CofA) invalid. When changes are referring to other changes, they shall be approved either. Process: Application. shall be made as established by the Agency, shall include a description of the change identifying all parts of the type design and the approved manuals affected by the change; and the certification specifications and environmental protection requirements with which the change has been designed to comply. shall include an identification of any re-investigations necessary to show compliance. shall include the necessary changes to the operational suitability data. Establishment of Certification Basis. shall show compliance with the certification specifications in effect at the date,(or previous if not significant) of the application for the change. Design change. Compliance demonstration. Issuance of approval

Supplemental Type Certificate

Application. Shall be made as established by the Agency. Arrangement with the type-certificate holder: the type-certificate holder has advised that it has no technical objection (NTO) to the information submitted for STC application, and the type-certificate holder has agreed to collaborate with the supplemental type-certificate holder to ensure discharge of all obligations for continued airworthiness of the changed product. Changes to that part of a product covered by a supplemental type certificate: Minor changes shall be classified and approved in accordance with Subpart D. Major changes proposed by the supplemental type-certificate holder itself may be approved as a change to the existing supplemental type-certificate. The rest of the major changes shall be approved as a separate supplemental type-certificate in accordance with Subpart E.