Sector Skipping
Sometimes, flights pass through an Air Traffic Service (ATS) sector for only a brief moment—this is known as sector clipping. Sector skipping is a procedure that allows a sector within a flight’s sequence to be bypassed. This means that communication with the flight crew goes directly from the previous sector to the next one.
Benefits
This approach has several advantages. First, it leads to fewer frequency changes, which minimizes disruptions. It also lowers the chances of losing communication due to issues like poor readbacks or equipment errors. As a result, pilot workload decreases because frequency changes can interrupt other important tasks. Similarly, controller workload is reduced since the sectors involved do not need to handle additional communication tasks if a flight is skipped.
Example Situations
There are different scenarios where sector skipping applies. For very short clips, aircraft may only be in the skipping sector for less than a minute. In cases of longer clipping near sector boundaries, controllers might decide against transferring the aircraft if there’s no significant benefit. Additionally, when an aircraft is set to enter a skipping sector for a few minutes and then return, skipping can ease the workload for both controllers. Vertical skipping is another option, especially for thin sectors handling overflights. However, this situation is riskier, as vertical separation diminishes faster than lateral separation.
For example, at cruising level FL 390, a flight might briefly pass through Sector 2 while climbing to FL 350 and then to FL 370 as it exits.
Risks
While sector skipping enhances efficiency and safety, there are inherent risks to consider. One major concern is conflict overlooking, as the track color changes to “unconcerned,” making conflicts harder to identify. Another risk is having no contact with an aircraft in the sector; the controller must ensure safety even without direct communication. Unexpected situations may arise, leaving less time for reaction. Misuse of the skipping procedure can also pose dangers if not applied carefully, as it requires discretion from controllers.
Contributory Factors
Several factors can increase the need for sector skipping or affect its associated risks. The shape and size of sectors play a crucial role, as does the implementation of free route airspace (FRA), which allows greater flexibility but can lead to more sector clipping. Higher traffic levels often necessitate more sectors, leading to more opportunities for skipping. The use of “unconcerned” track label colors can help controllers focus on active traffic but may also mask potential dangers.
Defences
To mitigate these risks, sector design should account for potential skipping scenarios. Regular reviews of sector boundaries can help. Increased vigilance is essential; controllers must stay aware of all aircraft in their sectors, even those not in contact. Clear definitions of acceptable conditions for skipping are necessary, including parameters like maximum clipping time. System support features, such as distinct color indicators on track labels, can help controllers remember when a flight is being skipped while not drawing too much attention.
In summary, sector skipping can enhance efficiency in air traffic management, but it requires careful consideration and appropriate measures to ensure safety.
