Lots of aircraft get modified so they can undertake new activities. The CAA has now made it more straightforward to apply for flight tests and related approvals.

Perhaps you want to add a cargo pod to your aircraft, or you need to modify the spraying gear for your agricultural operations. Depending on the design change you wish to make, you may need to carry out some flight tests as part of demonstrating the modified aircraft meets the requirements for a supplemental type certificate (STC) or modification approval. Note, this does not apply to operational check flights post maintenance.

Experimental flight testing is a highly controlled process in which an appropriately qualified pilot completes a series of flights to make sure the modified aircraft remains safe to fly.

We’ve made it simpler for you to prepare an application and to see what stage your application is at. This should mean time-sensitive information such as medical and biennial flight review dates are still current when your test pilot approval application is processed.

You can find information about these changes at the end of this article.

Flight tests require the CAA to issue a test pilot approval for the pilot, and a special category certificate of airworthiness (experimental) for the aircraft. Both approvals are contingent on an accepted test plan – this is the step that was previously unclear. Guidance for these is in the CAA’s advisory circulars listed at the end of this article.

As with many other activities, the CAA uses a risk-based approach to assess applications for flight testing. This is reflected in the four different categories of experimental flight testing (see AC19-1 Test Flight Approvals), which determine the different levels of experience and qualifications expected of a test pilot, depending on the test activity and future operations.

What operators need to know

While operators and owners usually ask a Part 146 design organisation to manage the test flight process as part of the modification, it’s still important you understand that the process can take time, so factor that into your planning.

It can take between six and eight weeks for the CAA to complete the assessments for the flight test approval, and longer if there are inaccuracies or missing information requiring documents to be reviewed and resubmitted.

So, using a Part 146 design organisation to manage the process is to your advantage and likely to reduce review cycles.

Category 3 flight testing workshops

You can learn more about the process changes described in this article at our Category 3 flight testing workshops. These workshops are restarting in 2025 and will teach you what’s required and expected from Category 3 test flying in New Zealand (see AC19-1 for categories).

The workshop is mainly aimed at pilots with limited test flying experience who’ll be involved in Category 3 test flying in the future. It will also benefit anyone who’s likely to be involved in aircraft test activities in the future, including engineers. The workshops also provide general flight testing advice useful tp all categories.

You can register your interest at:

Category 3 Test Flying Workshop

Special category testing

Some special category aircraft (such as amateur-built or warbirds) require a period of flight evaluation using a special category certificate of airworthiness (experimental).

This type of flight testing is usually category 4. Apply for the special category you’ll be operating under, using one of these application forms:

Application for special category airworthiness certificate (experimental) [DOCX 61 KB]

Application for special category airworthiness certificate (exhibition limited) [DOCX 59 KB]

Application for special category airworthiness certificate (amateur-built) [DOCX 59 KB]

Application for special category airworthiness certificate (LSA) [DOCX 60 KB]

Before applying for test pilot approval.

For amateur-built aircraft, applicants will be required to have a thorough knowledge of FAA's handbook:

AC90-89C Amateur-Built and Ultralight Flight-Testing Handbook(external link)

More information

The new process for flight test activity, and updated forms for test pilot approval and the special category certificate of airworthiness (experimental) are now on the CAA website at Flight test and test pilot approval.

For more information on the STC process, see the article in Vector (Winter 2024) The STC approval process.

Advisory Circulars

AC21-10 Experimental Flight Testing Guidance – find out what’s in a test plan, and more.

AC19-1 Test Pilot Approvals – for guidance on categories of flight testing, test pilot requirements and so on. See also Flight test and test pilot approval. 

AC21-3 Product certification – Airworthiness certificates in the special category.