Q. My in-laws' China Eastern flight from Heathrow to Shanghai last Saturday was four hours late due to the National Air Traffic Service (NATS) issue. Can they claim compensation? Steve Wong, Surrey
A. No. The equipment failure that disabled part of the NATS air-traffic control centre led to delays and cancellations across the UK. The reduced capacity affected practically every flight from around 6am.
Heathrow was hit more severely than other airports because it works close to full stretch. More than 200 domestic and European flights were cancelled before the bug was fixed early on Saturday evening.
Your in-laws were among the tens of thousands of travellers who faced long delays. Their China Eastern flight eventually departed at 1am – long after operations normally end at Heathrow.
Under European law, airlines must compensate passengers who arrive at their destination three hours late or more. But the carrier avoids liability if the cause was "extraordinary circumstances, which could not have been avoided". The IT collapse at NATS headquarters at Swanwick in Hampshire was plainly beyond the airlines' control.
What about travel insurance? Some policies provide cash compensation for delays, but these kick in only after a wait of 12 hours. If your in-laws had onward transportation booked, such as a domestic flight or train, they might be able to claim.