BM pitch-angle distributions (PADs) averaged over different energy ranges (indicated in the title of each plot). The colour coding represents the logarithm of the electron VDF. The vertical black lines are the same as in Fig. 5 and denote the intervals of integration of electron VDFs shown in Fig. 8 and the snapshot waveform interval. The gap in the data set beginning at around 06:06:00 is due to the extreme elevation setting in the relevant EAS head (see Fig. 3).