It’s Been a Challenging Week for Air Traffic Control. Firstly, on Tuesday we had an issue with the Central Flow Management Unit (CFMU), which coordinates supply and demand in the air traffic network. This lack of ability to coordinate demand across Europe resulted in some substantial delays and severe traffic flow restrictions at a number of major European airports.
Then, on Wednesday the UK National Air Traffic Service (NATS) introduced their new electronic flight strip system to the London terminal area. While it caused a few minor delays this has, so far, passed by largely without incident, by which I mean major delays.
Finally there were two closures of Gatwick Airport on Saturday and Sunday nights because of lack of air traffic controllers, which hints at some structural issues within ATC. The Notice To Airmen (NOTAM) issued about the closure said that Gatwick would be unavailable at certain times during the night because no ATC service would be available due to ‘short notice sickness’. Although the word 'closed' was not used the phrase ‘zero flow rate’ was used, which essentially means Gatwick was closed without actually saying as much.
Around two years ago as part of a cost-saving exercise Gatwick Airport outsourced it’s aerodrome control from NATS, who had provided the service for many years, to Air Navigation Solutions (ANS), which is part of the German Air Traffic Service Provider DFS. NATS staff are well-trained, have solid terms and conditions and a good pension package, but this also makes them relatively expensive. As with many things in life though, it seems that you get what you pay for with ATC. It was planned that NATS staff would remain working alongside ANS at Gatwick until the former personnel transferred back to NATS units in March 2018, which has just happened. Colleagues in the ATC community have told me that during the time NATS and ANS were working in parallel, there were difficulties validating the new controllers so that they were legal and competent to control the airfield independently without being mentored. Equally colleagues in ATC, at Gatwick specifically, reported that the unit was short-staffed and that a combination of voluntary and enforced overtime has been employed to cover the gaps. The effective closure on Saturday and Sunday nights led a Gatwick Airport controller to tweet:
Three ATCOs on a night shift, last night and tonight and two of them happen to be sick at short notice. Remaining one has to have a break at some point.
He also tweeted that:
Resource is tight everywhere, not just at LGW. Already several instances of approach function unavailability over night due to staffing at TC [Terminal Control] this year.
Gatwick Airport and the CAA will no doubt claim that closing the airfield (or applying zero flow rate) was the safest option and in that we agree. They have to meet their legal obligations for controller rest and their duty of care to passengers and staff. The real concern is however, that the UK’s second largest airport, and the busiest single runway airport in the world, has found itself in a situation with so little ATC cover that the airport has been forced to close, albeit at the moment only for short periods at night. This is also not an isolated example. In August last year, and again last month, Stansted Airport was forced to 'close' in a similar way because of lack of staff in air traffic control.
The key questions at this stage seem to be where is the cover for unforeseen events such as sickness? If as asserted, resource is tight everywhere, what is being done to address this shortfall without placing a further burden on the existing controllers? The difficulty with enforced and even voluntary overtime to cover shortfalls is that it covers up the underlying staffing problems while at the same time the probability of fatigue issues increases. While the whole industry is debating the issues surrounding pilot fatigue, controller fatigue is equally dangerous and receives comparatively less attention.
Having redundancy is a key component to maintaining safety in aviation: it’s why transport aeroplanes have two engines, backups for each major system and the main reason we have two pilots. Outsourcing to cheaper air traffic service providers might produce cost savings for the airports, but recent events demonstrate that sufficient depth of redundancy may not be available to guarantee continuity of this safety-critical service through unforeseen events at our major airports.