Automation strategies within the Initial Submission process (Part 1 of 2)

Efficient management of airport slots is very challenging nowadays. Air traffic grows and so does the amount of fully coordinated airports. Especially during the Initial Submission airlines needs to be sure to achieve an optimum slot utilization. Automation can support here tremendously.  

Initial Submission as a key milestone in Slot Management

It is time again! In exactly one week, on Monday, April 22, 2019, the Initial Submission phase starts ending with its final deadline on Thursday, May 16, 2019. The Initial Submission is a key milestone in Airline Slot Management. It is the date when airlines usually submit their initial slot request for the corresponding season to the airports coordinators.


Slot allocation and “Grandfather Rights”

Slots are initially allocated twice a year (summer and winter season) at coordinated airports. They depend on the day and time but not necessarily the flight number. Slot allocation is a complex issue. Technically speaking there are no property rights defined for slots for neither the airport nor the government nor the airlines. Bottom line: None of them owns a slot.

However, the so-called “Grandfather Rights” principle exists. This is an essential element within the slot allocation process. These Grandfather Rights describe the rights of airlines to use take-off and landing slots (times at which the aircraft is allowed to leave and arrive) at an airport that they have always possessed. Airlines are also not forced to give or sell them to other airlines. The Grandfather Rights entitle a carrier to continue using the same slot in the next scheduling period, provided that it has used that allocated slot for at least 80 percent in the previous period – which is called the “80/20” or “Use it or lose it” rule. Therefore, every flight cancellation or adjustment may have an impact on the right to use this respective slot for the next season. The slot coordinator of each coordinated airport hereby decides if airlines can keep using their Grandfather Rights by applying the Use it or lose it rule. However, airline and coordinators not always have the same view here.

Let us have a deeper look into the interplay between airline and coordinator during the Initial Submission:


Slot Historic List (SHL) message as starting point

Approximately six months before the start of each scheduling season (summer or winter), the coordinators calculate the acknowledged and rejected historic rights of each airline, based on their information about slot misusage and slot cancellations with reference to the Historic Baseline Date of the previous equivalent season.

As a next step, they notify via a Slot Historic List (SHL) message the respective acknowledged and/or rejected historic rights to each airline. The airlines then have a period of about three weeks to file their claims in case they do not agree to the coordinator’s calculation.


Initial Submission

Following the recognition of historic rights and during a period of approximately four weeks, the airlines may submit their initial slot request for the corresponding season. This may include the confirmation of historic rights, their modification and/or the request of new flights. The initial and final dates of this period are established worldwide on an (bi-)annual basis by the industry and notified by the relevant Slot Coordinator.

For the following winter season 2019/2020 the following dates are published by the IATA:


Deadline / Event / Action

22 APR 2019

SHL Deadline (Historic slots distributed by coordinators)

09 MAY 2019

Agreed Historics Deadline

16 MAY 2019

Initial Submission Deadline

06 JUN 2019

SAL Deadline (Initial Slot Allocation distributed to airlines)

18 - 20 JUN 2019

IATA Slot Conference 144 in Cape Town, South Africa

15 JUL 2019

Slot Return Deadline

16 JUL 2019

Reallocation of slots (until 31 AUG 2019)

31 AUG 2019

Historics Baseline Deadline (start of “80/20” usage calculation)

27OCT 2019

Start of Winter Season 19/20

28 MAR 2019

End of Winter Season 19/20


The recognition of the historic rights issued by the coordinator plays a very important role in the airlines’ slot management process. Within this short period between receiving the SHL and the final Initial Submission date, the slot managers are quite busy in evaluating the coordinator’s SHL results against their own slot utilization calculations. However, many of them still do this in a highly manual way, using for instance Excel, telexes and e-mails.    

However, efficient management and monitoring of airport slots is getting more and more challenging nowadays. Air traffic grows and so does the amount of fully coordinated airports. Additionally, airlines are confronted with increasing schedule/operational changes during the season resulting in an increased number of change messages. Since it is one big task during the Initial Submission process to detect new slots and re-used slots, it might get critical for an airline if slots at certain airports might be left unused or even be lost due to human/manual error. Hence, especially the Initial Submission Slot-/Schedule Manager needs to be sure to have checked all the airport slots held and required in order to achieve an optimum slot utilization.

From my point of view, nowadays optimum slot utilization can be achieved with a minimum of manual effort. To make this very important process more efficiently, IT support is one powerful way to omit the manual writing of telexes, e-mails and filing as well as working on laboriously Excel sheets. Especially as the Initial Submission is a recurrent airline core business process that has a lot of potential to be accelerated and facilitated with IT and automation support. 

The following five steps ideally are to be executed during an Initial Submission:

Step 1: Historic Data Collection

  • Use coordinator SHL
  • Use own view on historic slot set
  • Create a slot set containing historic information consolidating both

Step 2: New Schedule

  • Use target schedule from Schedule Management system
  • Create target slot set

Step 3: Linking / Matching Activities

  • Link of the two slot sets (historical and new)
  • Link of single slots (matching)
  • Optimized matching helps reusing historic slots

Step 4: Initial Submission

  • Generate Action Codes
  • Send the Initial Submission requests

Step 5: Slot Initial Allocation List (SAL) Message Processing

  • Receive SAL
  • Link it to right slot

Within the second part of my blog I will focus on IT supported (semi-)automation strategies around these five steps. They are able to make the Initial Submission process more efficient and less error-prone.

If you have any questions regarding the Initial Submission, please do not hesitate to contact me here. In addition, I look forward to receiving feedback from you.

In case, you already look for eligible IT support for your Initial Submission, kindly click here.


For part 2: Automation strategies within the Initial Submission process (Part 2 of 2)