August 2023 NATS outage
A single corrupted flight plan file downed NATS' automatic flight plan processing system, triggering chaos across UK airports on a bank holiday Monday. The Civil Aviation Authority later said the company needed to review its contingency plans, and airline bosses said the outage cost them over £100 million in refunds and compensation.
Thousands of flights were disrupted and airlines faced a compensation bill exceeding £100 million.
The CAA told NATS to overhaul contingency plans, yet a similar system failure recurred in 2025 and again in 2026.
It was the first of three major NATS failures that followed the same pattern, raising the question of whether the company has durably fixed its systems or is applying patches.
