# Additional ASMA Time

The Additional ASMA time is the difference between the actual ASMA transit time and the unimpeded ASMA time calculated for non-congested conditions.

Minute.

## Calculation of the indicator

Let

• $$c$$, a combination of aircraft class, ASMA sectors and arrival runway, as described in the technical note for [unimpeded ASMA time](/definition/unimpeded-asma-time/),
• $$f(c)$$, a flight characterised by a combination $$c$$,
• $$\textrm{AcASMA}(f(c))$$, the actual [ASMA transit time](/definition/asma-transit-time/) for a flight $$f(c)$$, i.e. the elapsed time between the last entry of the flight $$f(c)$$ in its ASMA sector and its actual landing time ([ALDT](/acronym/aldt/)),
• $$\textrm{UASMA}(c)$$, the [unimpeded ASMA time](/definition/unimpeded-asma-time/) for a combination $$c$$.

The additional ASMA time, $$\textrm{AdASMA}(f(c))$$, is calculated for each flight $$f(c)$$ as the difference between the actual ASMA transit time $$\textrm{AcASMA}(f(c))$$ of the flight and the unimpeded ASMA time $$\textrm{UASMA}(c)$$:

$\textrm{AdASMA}(f(c)) = \textrm{AcASMA}(f(c)) - \textrm{UASMA}(c)$

The additional ASMA time, $$\textrm{AdASMA}(c)$$, for a given combination $$c$$ is the average of the additional ASMA time, $$\textrm{AdASMA}(f(c))$$ of all the flight $$f(c)$$ characterised by that combination $$c$$.

The additional ASMA time, $$\textrm{AdASMA}$$, for a given airport is the weighted average of the additional ASMA time, $$\textrm{AdASMA}(c)$$, for all the combinations $$c$$ at that airport with their probability of occurrence.

## See also

Additional ASMA time methodology