Lufthansa Systems Blog

The need to inform and to be informed

Classic message information flow
Classic message information flow

Feb 17, 2021

Massive flight changes and cancellations are ubiquitous. Schedule volatility is increasing around the globe. No airline is able to create its schedule on a seasonal base. Even in stable conditions, getting timely schedule information is a challenge. During a pandemic, it is needed more than ever.

Airlines are responsible for providing up-to-date schedule data in time and need to be informed by partners about changes in the partner network. The shorter the time to departure, the more time critical is the need to have accurate information.

“Push Principle” – classic schedule data provision

The traditional way of sharing schedule data is based on the Push-Principle. The airline creating the change informs interested parties pro-actively by sending the required information. This process can even be time-triggered to fixed dates and times, or can be an event-triggered action. A manually initiated task is also possible but requires that the Schedule Manager is working in the office and has time to perform the task.

For time-triggered provision of schedule information, the data is typically converted into the standard IATA format SSIM, Chapter 7, and the distribution follows a pre-defined frequency, e.g. on Mondays and Wednesdays on 08.00 am.

This communication behavior is the most used and has been the best practice between collaborating airlines. They send their schedules back and forth on mutually agreed patterns. An analysis of 125 airlines showed that the majority of airlines deliver their schedule only once (43%) or twice (12%) a week to partners. This might be sufficient if schedules are stable – but in the current times, we are far away from stable schedules.

Figure 1: From 125 airlines analyzed, more than 50% exchange their schedules only just once or twice a week


Some airlines distribute their schedule data event-triggered. In this case, it is also the creating system detecting a change and informing (ideally according to predefined rule sets) the interested party by sending a telex/type B message (SSIM Chapter 4/5) or even a simple email.  The challenge is that the receiving partner might lose the overview in case of cascading schedule changes or because of the amount of schedule messages. In addition, the type B communication usually creates message transfer costs.

Considering the current schedule volatility, it is highly recommended to exchange the information as often as possible. Once or twice a week is not enough to bring out the best in a partnership – because partners are not informed about schedule changes at short notice. Best in class would be a real-time communication. To achieve this, a strong tool must be available on sender and recipient side.

Figure 2: Monday is the preferred day for schedule data exchange


“Pull Principle” - Get only what you need at the time when you need it

IATA recently commented in one of its publications: “Data is shared when needed rather when using a fixed schedule”. In contrast to the (pro-)active distribution of schedule data, interested parties can just send a request to the system where the data stored. Thereby a kind of communication between sender and recipient is established. The recipient detects which kind of data is needed, e.g. a specific flight at a specific date, puts over this request to the sender and the sender answers by provision of the requested data. “Get only what you need” – that’s the motto. Furthermore, the communication can be settled on a modern interface technology (e.g. REST API) in a modern communication format (like xml). There might be an unpredictable request volume causing a slow system performance, but, this challenge can be solved by load control and access rights mechanisms.

What should or can airlines do?

In order to survive and emerge stronger from the crisis, airlines have to face challenges and react quickly. Rigid processes or systems that cannot support the changing market requirements should be questioned, and potentially updated or replaced with better ones. Today, it is vital for airlines to share and receive up-to-date schedule information in time.  Airlines have to have a central place where all required schedule information is available, and functionality supporting the automated bidirectional transport of schedule data in the classic and modern style.  


Tags: code sharecode-shareschedule dataschedule data exchangeairline co-operationschedule deliveryalliancesco-operationjoint venturestar allianceskyteamoneworldnetwork managementLufthansa Systems Blog
Michael Becker
Senior Product Manager
Author-page, 12 posts
Lufthansa Systems Blog