Managing fatigue risk solely through rigid rules on minimum rest and maximum duty time is often an imprecise, hit-or-miss approach. Generally, tightening these restrictions can reduce fatigue risk on an individual level: the less a person works, the less likely they are to make fatigue-related errors that compromise flight safety. However, what if a rule change, while benefiting individual crew members, actually increases overall risk exposure for the airline?
Consider, for instance, a reduction in the maximum Flight Duty Period (FDP) allowed for overnight flights. While a stricter FDP limit may benefit one individual on a single duty, it can also result in the need for more night shifts, which can lead to a higher number of consecutive night duties. This, in turn, is likely to more sleep debt being accumlated across the crew. Such an outcome could ultimately increase the airline’s overall fatigue risk exposure. Perhaps additional rule adjustments are needed to achieve a more balanced solution?
The good news is that crew scheduling rules can be refined and systematically improved. Many airlines already leverage bio-mathematical models (BMMs) in their pairing and rostering processes, incorporating a “fatigue penalty” within their optimization algorithms. This penalty effectively signals to the scheduling optimizer that fatigue-inducing shifts should be minimized according to the operator’s chosen priority level, based on the ALARP principle.
One advantage of this approach is the flexibility of the penalty parameter: flipping it from positive to negative, for instance, would ironically make fatigue “desirable” to the optimizer, enabling an identification of any potential loopholes in the current rules, such as poorly written restrictions for consecutive night shifts (as in our earlier example). While this exercise is purely hypothetical (and none of the resulting rosters should be used), it helps highlight weaknesses within the rule sets, enabling airlines to effectively patch these vulnerabilities.
Curious about which rules may be overly restrictive and limit crew efficiency? Stay tuned for a follow-up article exploring also how to identify and adjust the rules to release additional efficiency. In the meantime, this document offers a deeper dive into aligning your crew scheduling rules with the latest science. Enjoy exploring!
Comments