How can you build up a robust schedule in Flight Scheduling? (Part 2 of 3)

How do you balance punctuality vs. productivity? Within this three-part joint blog sequence my three colleagues and I share five approaches towards minimizing propagated delays and increasing aircraft utilization by robust scheduling.

Hello and welcome back to our second joint blog about how to build up a robust schedule in Flight Scheduling.

In the first part we were elaborating the effect of rotational as well as maintenance buffers on a robust schedule. In this blog we pick up the third buffer topic again and have a deeper look unnecessary rotational buffers.

(3) Eliminate unnecessary rotational buffers

Trickier are the “unnecessary buffers”, because during normal operations you usually are not aware of them. They cost you block and ground time that you could use for further productivity and revenue optimization of an aircraft.

One example:

An A320 flight from TXL to FRA is always planned with 45 minutes block times. But after comparing the planned versus the flown flight schedule you find out that it actually only takes 40 minutes. Hence you can minimize the block times for each by 5 minutes. Having 10 flights a day, this is already 50 minutes.

These unnecessary buffers can as well be identified by comparing the planned against the “flown” schedule”.

When talking about buffers the Flight Scheduler does not only have to decide where to put the buffer (to the Blocktime and / or the Groundtimes), but also how long this buffer shall be. This important question can be solved as followed:  In order to find the right buffer length, for instance for all delayed flights coming from BKK, the most simple way is to look at the Gaussian distribution for all these flights: First you should sort out all spikes. Then you have to decide based on your experience, which average value for the block time you will choose for this specific flight: Is it the median, the 80% value or the 60% value – with descending percentages giving you less and less buffer time.

In the next and final blog we will take a broader cross-departmental look by examining interdependencies with crew management. In detail we make up our minds about the benefits of considering the crew pairings while creating the flight schedule and how better communications between Flight Scheduling and Crew Management during the rostering phase might save crew costs.

Until then we are look forward to hearing your feedback on this blog or sharing your ideas about how flight schedules can be made more robust.



Michael, Judith, Ensuch & Sascha


Part 1 and 3 you can read here:  

Part 1:

Part 3:


This blog joint sequence is a joint publication of: