TDI - Turnaround Delay Indicator
The Turnaround Delay Indicator (TDI) equals the DDI-G but neutralizes early arrivals. The actual arrival time is set to the scheduled arrival in case of an early arrival.
$$ \mathrm{TDI} = \mathrm{Departure\ Delay} - \begin{cases} 0, & \mbox{if } \mbox{Inbound Delay} <= 0 \\ \mbox{Inbound Delay}, & \mbox{if } \mbox{Inbound Delay} > 0 \end{cases} \ [min] $$