- your organisation details, including contact details for the proposed certificate holder
- full details for the proposed change including the reason for the change
- your draft certification plan
- your aviation reference number.
A supplemental type certificate (STC) is an approval of a design for a change to a type certificated aircraft, engine or propeller. You need an STC when the change is not extensive enough to need a new Type Certificate (TC).
How to apply for a supplemental type certificate
Have this information ready before you begin:
Complete the form
Use Form 733 Application for a type certificate or supplemental type certificate LINK to apply for an STC.
Use this form if you are seeking approval of a change to an:
- aircraft engine
- aircraft propeller.
We gather and store your information according to our privacy statement.
Submit the form
Submit your application and supporting documents to us by following the instructions in the form.
After you submit the form
We will review your application to ensure it is correct and complete. We will contact you if we need more information.
Pay the fee
We charge a fee for the assessment and inspection of your:
- certification plan
- related tests or reports.
We'll send you an estimate of the costs to assess your design and issue the STC, based on an hourly rate.
You must pay the fee before we can process your application.
Cancel an application
To cancel your application after paying the fee, contact us in writing. We will charge costs for any work completed before you cancel.
Assessment timeframes vary and rely on:
- when we receive your payment
- the quality of your documents
- the availability of our resources.
We'll contact you if the recommendation varies from what you applied for. We'll also contact you with notice if we accept or decline your application.
We will calculate the actual costs of the assessment process. We will then either process a refund or raise an invoice if required.
If approved, we'll email you a copy and send the original by mail.
See AC 21-15 supplemental type certificates for detailed guidance on STCs.