Volume 20 | Thursday, December 17th, 2020
Winter Weather and Traffic Initiatives
Welcome back to Jump Seat. This week, we’re covering a weather phenomenon that is quite timely: Winter Weather. Winter weather poses several flight hazards including aircraft icing, reduced visibility, and poor braking action on snow and ice-covered runways. Furthermore, pilots often deal with lengthy delays resulting from low aircraft arrival and departure rates or deicing at an impacted airport. It is important for operators to be prepared for adverse conditions and aware of their options during the winter season.
Snow, sleet, and freezing rain are the most common precipitation types associated with winter storms. The temperature profile of the atmosphere determines which precipitation type occurs at the surface. If the temperature profile is at or below 0°C then snow will fall at the surface (Figure 1). In order for sleet or freezing rain to occur, there must be a temperature inversion in the lower levels of the atmosphere (~FL050-100), where temperatures are greater than 0°C to allow for melting of the snowflake. The thickness and maximum temperature of the inversion will determine whether sleet or freezing rain occurs at the surface. If the inversion is shallow and does not allow the snowflake to completely melt, then sleet will occur (Figure 2). A thicker inversion will allow the snowflake to completely melt into liquid. If surface temperatures are below 0°C, the liquid will freeze on contact creating freezing rain (Figure 3).

FAA Initiatives

The FAA has several initiatives that are used to efficiently manage traffic volume including ground stops, ground delay programs, and required routes. These initiatives are most often used during high volume traffic days that coincide with the holiday season and during winter weather events. If a winter storm impacts a region, expect significant delays and airport closures for snow removal and aircraft deicing. If your destination airport is impacted, you could be caught with an EDCT (Expect Departure Clearance Time).

When flying to popular winter locations, such as the Ski Country airports (ASE, EGE, and RIL), expect the potential for ATC to issue required routes as noted in the FAA playbook. The “Ski Country 1 or 2” routes are typically issued the day of by the FAA Command Center after examining volume heading into these Colorado airports. Keep in mind, slots are not required at these airports but ramp space can be limited. As a result, ground delays are possible even on VFR days. Elsewhere, expect heavy volume between the US Northeast, Florida, and the Caribbean over the holidays and into the winter months. ATC will typically issue required playbook routes here as well.
Eurocontrol Initiatives

Eurocontrol’s Network Manager Operations Centre (NMOC) uses a similar approach to the FAA when managing adverse weather and traffic volume across Europe. Air Traffic Flow and Capacity Management (ATFCM) is used to optimize capacity, increase efficiency, and mitigate excessive traffic loads on ATC centers and airports. If measures throughout an airspace or at an airport are necessary for ATFCM, then Calculated Take-Off Times (CTOTs) will be issued 2 hours prior to the filed departure time for all operators that are impacted. 

The ARINCDirect Flight Operations team can assist by eliminating or reducing flight delays whenever an EDCT or CTOT is issued. We monitor the latest ATC telecons for updated information in the domestic US National Airspace (NAS) and also keep a close eye on Eurocontrol’s Network Operations Portal (NOP). We have the capability to coordinate delay relief directly with the FAA and the NMOC.
Did you know?
  • We have placed the FAA/ATC NEXT DAY PLAN and the LATEST EUROCONTROL NETWORK PLAN on our flight planning page, as seen below. It is recommended that these reports are reviewed the night before or the morning of your departure.
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Thank you for reading Jump Seat throughout 2020.
We wish you a Happy Holiday and a joyful New Year!
We want to invite you to take another tour of our upcoming webinar training events to rekindle your knowledge of new features and some existing features. Feel free to join us online and register for these sessions listed on the ARINCDirect Help and Training page.