Industry group Airlines UK said the report, compiled for the Civil Aviation Authority, showed air traffic control processes were "wholly inadequate". An independent interim report into what went wrong, which was commissioned by the Civil Aviation Authority, found the problem started when the NATS system struggled to cope with an unusual flight plan and shut down. NATS engineers working on site could not fix the issue, so the problem was escalated to on-call engineers higher up the chain. Help was then sought from another engineer, and system manufacturer Frequentis was called after four hours, when stored flight plan data had run out. Communication issues, the report says, "resulted in more uncertainty and more severe impacts on passengers and others than was necessary".
