Certification Services

STM Design Organization Approval (EASA.21J.633) was published by EASA (European Aviation Safety Agency) on 20 October 2017.
We develop changes and repair designs for domestic/international airlines, private aircraft operators and state aircraft in the technical fields covered by the STM DOA (Design Organisation Approval) business and approve them with EASA authorization. In this context, 44 projects were carried out between 2018-2020. Our company continues to carry out various projects, primarily THY and SunExpress companies at home with the design works carried out within the scope of approval, and the number of airlines we serve abroad has reached six.

In addition to our project activities, we provide consultancy services. Our studies in this context:

  • Providing design consultancy and airworthiness training to companies in the civil and military aviation industry
  • Providing support and consultancy to civil/military authorities and industry in the creation and maintenance of the infrastructure necessary to operate the certification process
  • Providing companies in the civil/military aviation sector with consultancy services for infrastructure and technical issues
  • Providing support and consultancy to companies in the design organisation and production organisation approval processes
  • Conducting design activities requiring STC (Supplemental Type Certificate) and ETSO (European Technical Standard Order), ensuring their approval (certification) through DGCA and validation by EASA, and providing consultancy services to the sector in these works.

Our Reference Projects

  • Fly Bosnia Airlines, A319-112 aircraft EYOF 2019 Wrapping Project
  • Nordwind Airlines, B737-800 Aircraft Painting Project
  • MNG Jet Airlines, Bombardier Challenger 605 aircraft Carpet Replacement Project
  • THY, A321 Neo Aircraft Mirror Mounting Project on Overhead Bins
  • SunExpress Airlines, B737-800 Placard Standardisation Project
  • THY, A340 aircraft Project of Relocating Portable Fire Extinguisher 

Our Current Projects

SunExpress Consultancy Service within the Scope of EASA DOA Certification

Training and consultancy services were provided to SunExpress within the scope of obtaining Design Organization Approval. As a result of the services provided, EASA European Aviation Safety Agency approval EASA.21J.557, has been granted to the SunExpress Design Organization on 10 July 2020.

STM experts are providing Compliance Verification Engineering support services to Sun Express Design Organization.

Minor Change Design and Minor Repair Design Projects

It contains the design data package required for the realisation of the project to meet the minor change and minor repair design requirements of domestic and international airlines and for the application of the change/repair to the aircraft.

Training Activities


  • Introduction to Airworthiness Certification
  • Introduction to EASA PART-21 Regulation
  • EASA Part-21 Regulation/Certification Training in accordance with Design Organisation Approval (DOA)
  • EASA Part-21 Regulation/Certification Training in accordance with Production Organisation Approval (POA)
  • Introduction to CS-25 Certification Specifications
  • Introduction to System Safety Assessment in Aviation Projects
  • SAE ARP 4761 Standard Rules and Methods for Operating the Safety Assessment Process in Civil Aviation Systems and Equipment
  • Basic Avionics
  • Introduction to Avionics Certification
  • SAE ARP 4754A Standard Rules for Developing Civil Aircraft and Systems
  • RTCA / DO-178 Software Certification Processes in Aviation
  • RTCA / DO-254 Hardware Certification Processes in Aviation
  • DO-160 Equipment Environmental Requirements Qualification
  • Aircraft Structural
  • Cockpit Design
  • Cabin Safety
  • Continuous Flight Availability and Operational Suitability Data (OSD)

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