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STC Twenty One

Aerospace Engineering

STC Twenty One Limited is a Design Organisation (DOA) located in the East Midlands. Our aerospace engineering service is approved and regulated under the UK Civil Aviation Authority (CAA).

STC Twenty One Limited provides UK CAA approved major STC (Supplemental Type Certificate) and minor changes/repairs for a wide variation of aeroplane and rotorcraft types.

The scope of approval held by STC Twenty One Limited permits design changes for the following:

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Aerospace Engineering


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.

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 a variety of aircraft.

We specialise in 6 key aircraft modification services including avionics systems, environmental control systems, cabin interior modifications, aircraft structure repair, flight testing aircraft and permits to fly. Discover more about our list of services below.

Aerospace Engineering


STC Twenty One is dedicated to providing career pathways in the aerospace and aviation community. Apply for jobs directly with qualifications and experience, plus you can find out more about positions in aerospace engineering from by clicking the link below.

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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).

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+44 1332 576830

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