Table 1  Description of the Study Sample,,,,,,,,,,,,
Operator,Model,Number,Average age (yrs),Average unscheduled landings,,,,,,,,
O1,M1,230,10.43,3.15,,,,,,,,
,M2,34,5.17,1.82,,,,,,,,
O2,M1,221,7.74,1.35,,,,,,,,
,M2,0,—,—,,,,,,,,
O3,M1,73,10.83,0.96,,,,,,,,
,M2,83,6.93,0.77,,,,,,,,
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