NATS Prestwick fault disrupts Scottish airspace in second outage

A connectivity fault at the National Air Traffic Services centre in Prestwick, Scotland, disrupted flights across Scotland, Northern Ireland and northern England on Monday 21 September, cancelling dozens of departures and arrivals and affecting some domestic and westbound trans-Atlantic routes. NATS described the problem as 'a connectivity issue with part of our systems network, specific to the operation in Scotland' and confirmed the fault had been fixed [Source: BBC News]. Transport Secretary Heidi Alexander said engineers had 'fixed the problem and systems are resuming,' warning passengers to expect delays 'as things reset' [Source: BBC News].

Aviation analytics firm Cirium counted 35 UK departures cancelled or not flown by mid-morning, alongside 37 cancellations among 3,048 scheduled arrivals [Source: Cirium]. Loganair cancelled 10 Monday flights, and Highlands and Islands Airports said all 11 of its airports were affected. Glasgow, Edinburgh, Manchester, Belfast International, Belfast City, Newcastle, Liverpool, Bristol and London City all reported delays or cancellations. The incident affected airlines including EasyJet (EZJ.L), Ryanair (RYA.IR) and Loganair.

The outage drew sharp criticism from airlines. EasyJet said the latest incident 'once again calls into question the resilience' of the system [Source: BBC News]. Ryanair chief operations officer Neal McMahon said NATS has failed to deliver 'either a reliable system or an effective back-up' [Source: BBC News]. Broader industry voices called for 'action and accountability' over UK air traffic control services.

The Prestwick incident is the second significant NATS disruption in a fortnight. On 8 September, a software defect at the Swanwick centre in Hampshire produced corrupted data and cancelled approximately 2,000 flights across the UK, with restrictions in place for about six hours and the resulting backlog taking more than two days to clear. NATS stated that Monday's Prestwick connectivity issue is unrelated to the 8 September software failure and that its preliminary report on the earlier incident ruled out military intervention and cyber-attack [Source: FlightGlobal]. Prestwick handles roughly 42 percent of UK air traffic, including North East Atlantic routes used by flights between the US and northern Europe, making disruptions at the centre consequential for transatlantic as well as domestic operations.

Sources: Bloomberg, The Guardian, BBC News, Cirium, FlightGlobal