In its simplest terms, an infringement occurs when an aircraft makes an unauthorised entry into controlled airspace.
This has the potential to affect other members of the flying public through the likelihood of commercial aircraft being re-routed or delayed.
Pilots must aim to ensure that an infringement isn’t assumed to be ‘minor’ or that they will eventually determine their position. The Distress and Diversion Cell can be reached on 121.5 and should be contacted as soon as a pilot believes they may have a problem. The cell actively encourages pilots to call them in order to stop the infringement from developing any of the effects mentioned below.
A few minutes of infringement can result in wide spread knock-on effects, beginning with traffic disruption. The controller must assume that the infringing pilot is lost and unpredictable, so a five- mile radius buffer around the infringer is established. This can begin a chain reaction as the buffer may encroach on an airport’s ILS (instrument landing system) or climbout, therefore inhibiting arrivals and departures.
A quick glance at the radar replays available through FlyOnTrack (flyontrack.co.uk) will give you an idea of how an infringement works and just how serious they are by illustrating the disruption that they cause. The radar playback below is taken from FlyOnTrack.co.uk and shows a ‘G.A. Infringer’ entering into Heathrow Class ‘A’ Airspace. More radar playback examples are available on the site.
While aircraft cannot land, they’ll be burning fuel and releasing carbon in a holding pattern, or sitting on the runway or gate missing their pre-planned slots. According to the CAA, an infringement by just one pilot can mean delays for up to 30 airliners and 5000 passengers and result in £50,000 worth of fuel being wasted.
Aside from financial costs and the disruption to commercial aircraft, infringements also pose a very real and significant threat to safety as a potential collision risk.
So what causes people to infringe?
At NATS we’ve now collected over 400 questionnaires from infringing pilots. Some of the most common reasons include complacency, pilot workload and distractions, the misreading of charts, poor or incorrect pre-flight briefing and misidentification of land features.
But for every reason for infringing, comes a reason why it can be avoided. If you have a transponder, then simply switching it on can make a difference. Mode Charlie (ALT) means that if you do wander where you shouldn’t, the controllers will at least have an indication of your altitude, allowing controllers to deal with the situation more effectively for you and the surrounding traffic.
Software, such as SkyDemon and Aware from Airbox, has been developed in conjunction with NATS to make pre-flight planning more effective. It also includes valuable elements that can warn you if you are about to enter controlled airspace, helping to eliminate accidental infringements.
Operations like those performed by the Distress and Diversion cell can be observed on ‘Visit ATC’ days, which are organised at locations across the country by the Airspace and Safety Initiative (ASI) of which NATS are a part. The opportunity to view live air traffic control operations in this way, aims to develop the mutual understanding between pilots and controllers.
Controllers are able to tell pilots where they are within seconds, but pilots must feel that they are able to ask for that help too. Through the initiatives mentioned here, amongst others, NATS is working to actively develop the positive relationship between the General Aviation Community and controllers in order to create a more effective, well informed and safer flying environment for everyone.
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