Fig. 4

SAFE model simulation predictions for the 20:00 flight schedule under the exemption and the CCAR-121 Policies, with A and B showing the outbound (manned by flight crews i and j) and return (manned by flight crews k and l) flights, respectively, and C and D showing the outbound and return (both manned by flight crews q and r) flights, respectively, under the CCAR-121 policy. A comparison of A and C shows the fatigue risk for flight crews flying under the exemption approach and CCAR-121 regulations on outbound flights. A comparison of B and D shows a comparison of the fatigue risk levels for flight crews flying under the exemption approach and CCAR-121 regulations on return trip flights. Note: The meaning of the level of risk represented by the different colours is determined by Table 3. PVG stands for Shanghai Pudong International Airport; FRA stands for Frankfurt International Airport; CKG stands for Chongqing Jiangbei International Airport; AMS stands for Amsterdam International Airport. The number at the end of the duty refers to the number of segments flown during the time on duty