Supplemental type certificates
What is a supplemental type certificate?
When a person develops the design of a change to a type-certificated aircraft, aircraft engine or propeller, that design must be approved before it can be used. A supplemental type certificate (STC) is one method of obtaining approval.
If you propose to develop the design of a major change to a type-certificated aircraft, aircraft engine or propeller you should seek an STC, especially if you wish to sell your design to multiple customers.
Further information is available in CASA Advisory Circular AC 21-15 "Supplemental Type Certificates - Certification".
How to apply for a supplemental type certificate
Submit an application for an STC. Your application should be accompanied by extra information that describes your design and shows how you intend to show compliance with the certification basis. The documents required to obtain an STC are described in AC 21-15.
Step 1 - complete the application form
You will need to complete a STC application form 733. Form 733 is in five parts (A-E).
The form provides guidelines that will assist you in completing the form correctly. Please read these guidelines carefully. If you have any further questions regarding the form and how to fill it out please do not hesitate to phone the CASA service centre on 136 773.
Form 733 - Application for supplemental type certificate can be downloaded from the CASA website.
All parts must be completed.
Part A - Applicant's details
This is where you will tell CASA who you are, whether you are an individual or company. You will need to provide your CASA aviation reference number (ARN).
Note: If you do not have a CASA ARN you must provide proof of identification or proof of your company's registration (see application guidelines for acceptable forms of identification).
If you are a foreign applicant you must provide your nationally recognised registration record.
Part B - Designation of aircraft, aircraft engine or propeller
In this part you will tell CASA about any changes you may be making to the aircraft, the country in which it was manufactured, who manufactured it and its model designation.
Part C - Description of proposed changes
This part allows you to describe in detail any changes you are making to the aircraft, aircraft engine or propeller you wish to be approved by issue of an STC. It will be of assistance to CASA if you provide the objective of your proposed change.
Part D - Declaration
By signing the declaration, you will be indicating to CASA that you have read the guidelines, completed the application in full and supplied all necessary documents required for the CASA service centre to process your application. It also asks if you are happy to correspond with CASA via email.
Step 2 - Submit application form
The form should be sent to CASA service centre
STEP 3 - Review of your application
The Service Centre will review the application to ensure that you have answered the relevant questions and provided any documents requested in the application.
Should the application be incomplete, the service centre will contact you and provide you with the opportunity to address the shortfall. Please remember that your application will be returned to you if you do not address the shortfall within a reasonable period of time.
Step 4 - Estimate of costs
An estimate of the cost to process the application will be forwarded to you. The estimate is based on an hourly rate and will cover CASA's assessment of your certification plan, witnessing of tests, review of reports, and other essential activities. An amount is also included to process and issue the STC. You will be advised at this time of any additional supporting documentation that is required. Payment of the estimate and submission of any additional supporting documentation requested will be required before CASA will commence work on the application.
A description of the estimate process is in CASA's fees and charges section.
Note: Having paid the estimate, should you at any stage during the assessment of the application, wish to cancel the application, notify the service centre in writing. CASA will recover costs for work completed up to the date of cancellation.
Step 5 - Assessment
The assessment timeframes and the proposed certificate issue date is dependent on the:
- Payment of the estimate or deposit
- Quality of your documentation
- Availability of CASA resources.
Step 6 - Recommendation
Once the assessment is complete, a recommendation to issue or not to issue the STC will be made to the CASA delegate.
If the approval varies from what you have applied for, or if the application is declined, CASA will discuss this with you.
Step 7 - Certificate issue
The service centre will reconcile the actual hours against the estimated hours for the assessment and either process a refund or raise an invoice for the additional costs. If approved, the STC will be faxed to you on the same day and the original forwarded by mail
Our commitment to you
We will advise on:
- Specific requirements and explain the application process to you
- Proposed completion date
- Changes to agreed timings or costs
We will also keep track of your application from the day it is lodged to the day of the certificate issue.
CASA is authorised under section 27AA of the Civil Aviation Act 1988 to approve this Form 733 and thereby collect the information you supplied in it. All such information received will be treated as being confidential. CASA is bound by the Privacy Act to safeguard personal information within the terms of that Act. CASA has a policy of publishing certificates on its website.