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Permit to Fly

A Permit to Fly is generally issued when a certificate of airworthiness is temporarily invalid, or when a certificate of airworthiness cannot be granted, but the aircraft is nevertheless capable of performing a safe flight. The Flight Conditions are those conditions or limitations necessary to assure such safe flight.

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Permit to Fly

Why Choose Us?

STC Twenty One has earnt the privilege from the UK CAA to approve and issue the Flight Conditions necessary to assure safe flight for large and small aircraft and rotorcraft, and to approve and issue the associated Permit to Fly. We can therefore provide a complete service requiring no separate applications.  

Services & Approvals
permit to fly stc twenty one why choose us

Permit to Fly

Services & Approvals

We aim to provide a 24-hour or better turnaround for approvals when necessary (provided all required data for safety assessment is available). Please call us to discuss your requirements and we will always endeavour to meet your schedule. 

STC Twenty One have issued over fifty approved Flight Conditions (with associated Permits to Fly where required). These have been associated with a range of customer needs, including Test Flights for the demonstration of compliance of modifications not then approved, ferry flights for overdue maintenance or repair of damage, and customer acceptance flights.

Speak to the Team
permit to fly stc twenty one services

Permit to Fly

Speak To The Team

Each of our engineers involved with Flight Conditions approvals has in excess of fifteen years’ experience and knowledge gained from Design Organisations including Type Certificate Holders, Maintenance Organisations and Operators. 


Peter Gaughan

Managing Director / Accountable Manager

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


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.

Permit to Fly

Contact Us

Need more information or want to arrange to meet us?

+44 1332 576830

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