The published roster sent out to crew, typically some ten days prior to the start of the month, constitutes not only a plan but also a ’promise’ to crew about their upcoming time off. Crew will make plans for how to use that time off with activities and gatherings with family and friends - plans not always easily altered.
When the company is forced to change crew rosters at short notice for meeting operational demands, crew are often 'squeezed' between the updated company plan and their own private commitments and obligations - and sleep tends to take the hit.
Unstable rosters are repetitively brought up by crew as a major concern from a fatigue perspective. So, what can be done? A good start is for the operator to quantify and track relevant metrics reflecting this problem. One metric to follow is SSR, the Spare time Survival Ratio, which reflects the percentage of time off in the published roster that remained time off in the flown roster. Another metric is CSR, the Connection Survival Ratio, which is the percentage of planned connections between activities that 'survived' from the publication through operation. These types of metrics will quantify the stability of the published roster and can be used for assessing and benchmarking the operation and verifying improvements over time.
So, how can an operator improve the situation? Efficiently creating robustness, if done without adding a lot of costly overhead, is something of an art. With the use of analytics over the historic delays and disruptions, it is possible in a structured way to re-distribute buffers in the crew rosters so that a cost-neutral plan with much higher stability can be achieved. Analytics solutions such as Jeppesen Calibration is now increasingly making this possible - enabling airlines to better keep their promises, leading to more alert and satisfied crew. Read more about Jeppesen Calibration here.