The idea that somehow flying the line specifically at United for years makes someone a good instructor is as nonsensical to me as the 1500 hr rule making a guy crop dust for 1000 hours. Flight time gives you experience, it doesn’t make you a quality teacher. Yes an instructor needs to be able to draw from experience teaching a lesson, but they’re not teaching experiences, they’re teaching an FAA-approved script written by United.

About the London CDA issue and < 8 years between the instructor and seat support:

Someone could have 15 years experience at United and have never flown to LHR before. The airbus fleet is getting new aircraft and United is expecting the airbus instructors to somehow know how to teach that stuff. That’s a United problem, not an instructor problem. United should be having their instructors be paid to be taught by the other fleets how to do the NAT stuff, but United doesn’t want to do that.