We explore the possibilities of measuring the longitudinal profile of individual air showers beyond
$X_{\rm max}$ when using very dense radio arrays such as SKA. The low-frequency part of the Square
Kilometre Array, to be built in Australia, features an enormous antenna density of about 50,000
antennas in the inner core region of radius 500 m, with a frequency band from 50 to 350 MHz.
From CoREAS simulations, a SKA-Low antenna model plus noise contributions, and adapted
LOFAR analysis scripts, we obtain a resolution in the shower maximum $X_{\rm max}$ and energy that is
considerably better than at LOFAR. Already from this setup, we show that at least one additional
parameter of the longitudinal profile can be measured. This would improve mass composition
analysis by measuring an additional composition-dependent quantity. Moreover, it would offer
an opportunity to discriminate between the different predictions of hadronic interaction models,
hence contributing to hadronic physics at energy levels beyond man-made accelerators.