TSO and STC Certification
Engineering Services for TSO and STC Certification
TSO and STC Certification is a forward-deployed engineering service for equipment, modifications, and design changes moving through TSO authorization or STC approval. Requirements management, design data structuring, test and analysis evidence, conformity, and FAA coordination are handled by certification engineers, with structured tooling used where it improves traceability.
What this supports
- Supplemental Type Certification (STC) under 14 CFR Part 21, Subpart E
- TSO Authorization under 14 CFR Part 21, Subpart O, including Letter of Design Approval
- Major repairs and major alterations under FAA Form 8110-3 and 8130-3
- Continued airworthiness documentation
- DO-178C software, DO-254 hardware, ARP4754B system, and ARP4761 safety evidence
The problem
Most STC and TSO delays come from documentation, traceability, and review cycles rather than the engineering itself. Requirements drift across program phases, evidence is difficult to assemble at submission time, and FAA findings cycle for months when the underlying record is fragmented. The cost lands on development budget, market window, and time to revenue.
How the engagement works
Structure the certification basis
The product is mapped to the applicable certification basis, including Part 23, Part 25, TSO, DO-178C, DO-254, ARP4754B, and ARP4761 as applicable. The initial requirements baseline and means-of-compliance plan are produced.
Maintain live requirements traceability
Every requirement traces to design, test, and verification evidence. When a requirement, drawing, or test result changes, downstream impact across design, code, tests, and verification status is visible immediately.
Coordinate test and analysis
Qualification testing under DO-160, software verification under DO-178C, hardware verification under DO-254, and system safety analysis under ARP4761 are coordinated against the requirements baseline.
Generate certification evidence
Plans for Software Aspects of Certification (PSAC), Software Accomplishment Summaries (SAS), compliance matrices, and TSO submission packages are prepared from the controlled evidence set.
Coordinate with the FAA
Submission management, ACO and DER correspondence, and finding closures are tracked in a structured way that survives across submission rounds and team transitions.
Distribute through the marketplace
Where appropriate after approval, the marketplace can help prepare the commercial offering and documentation package for buyer conversations.
Engagement model
Engagements begin with a scoped initial phase and scale by results. Certification engineers work directly with internal engineering and program teams. The commercial model is outcomes-aligned. Distribution through the marketplace is available as a follow-on engagement once certification is achieved.
Outcomes
Who engages this service
TSO and STC Certification engagements are sponsored by CTO, VP Engineering, Director of Certification, and Head of Airworthiness. Supporting teams typically include lead engineers, certification engineers, systems engineers, software and hardware verification leads, and program management at OEMs, suppliers, integrators, and aircraft modifiers.
Next step
Talk through the scope.
Send the aircraft, deadline, and current obstacle. We will use the first conversation to understand the work, the evidence involved, and the right next step. You can include a redacted sample if helpful.