Mr Gates has specialised in aviation-related law throughout his career. His clients include airlines, airports, ground handlers, financiers, manufacturers and their insurers. His practice has involved representation of operators and others domestically and internationally and he has been involved in more than 50 international aviation disaster cases in the course of his career. From 1997 to 2003, he was senior partner at the leading boutique aviation law firm Beaumont and Son (which subsequently merged with Clyde and Co), and, in 2003, he founded Gates and Partners, which, before merging with another UK law firm in June 2013, employed 60 lawyers specialising in various aspects of aviation law, with offices in five jurisdictions worldwide.
From 1998 to 2013, Mr Gates was the legal adviser to the International Union of Aviation Insurers (IUAI), a trade association comprising the world's leading aviation insurers. Mr Gates represented the IUAI as the principal observer on behalf of the IUAI at the diplomatic conference resulting in the Montreal Convention of 1999 on carrier liability to passengers, at the diplomatic conference in Montreal for the Conventions on Surface Damage and at the legal committee meeting in 2013 discussing changes to the Tokyo Convention on Offences Committed on Board Aircraft 1963. From 2006 to 2016, he was legal adviser to the British Air Transport Association, and, until its takeover, was also legal director of Kenyon International Emergency Services.
Mr Gates is currently the chief executive officer of Gates Aviation Ltd, which provides a range of services to the aerospace industry in a variety of areas, including dispute resolution, risk management and disaster preparedness and response. He is also legal director for the European Regions Airlines Association. He continues to advise a range of clients on disaster preparedness, insurance issues, aviation regulatory and competition disputes and related matters.