Flight testing is at the core of what Design Organisations must do in order to validate the operation and performance of a modified aircraft, as well as evaluate the functionality of new and/or modified aircraft systems during flight.
STC Twenty One Limited can help with all your flight test needs.
Flight Testing Aircraft
Why Choose Us?
At STC Twenty One Limited we employ a multi-disciplinary team of flight test experts who are well versed in the process and discipline of aircraft performance, stability and control, and systems testing and have conducted flight test programs around the globe in line with various regulatory processes.

Flight Testing Aircraft
Services & Approvals
At STC Twenty One Limited, we are proud to be able to offer the following Flight Test services:
- Aircraft performance testing.
- Aircraft stability and control testing.
- Aircraft Avionics and systems testing.
- Electro-Magnetic Compatibility testing.
- Flight testing unique aircraft modifications such as Vibration and Buffet testing of Large Radome installations.
- Smoke penetration testing.
We have a large breadth of experience in the Flight Test field. Below are some recent Flight Test projects:
- Flight testing of RNP-Approach systems on various EFIS and analog aircraft.
- Automatic pilot evaluation of ageing aircraft.
- Vibration and Buffet testing of a large radome installation on Airbus A330, Airbus A340 and Boeing 747 aircraft.

Flight Testing Aircraft
Speak To The Team
Our multi-disciplinary team of flight test experts have Decades of experience in flight test across rotorcraft, general aviation and large transport category aircraft.
We are equipped for all your flight test needs.
UK CAA Approved Design Organisation
STC Twenty One
All aircraft modifications and aircraft repairs are managed by our UK CAA approved Design Office represented by STC Twenty One (UK.21J.0198).
What We Offer
Services
STC Twenty One Limited holds a Part 21 Subpart J DOA enabling it to certify UK CAA approved STCs and Major Repairs. Additionally, where a design change or repair is classified as minor, STC Twenty One Limited is authorised to approve them under the DOA using approval reference UK.21J.0198 through CAA.
Our employees are spread across our Avionics, Mechanical, Quality and Commercial Teams with a high level of experience and certification enabling the company to perform specialised services on engines and aircraft. Read more about our Services.