WATCH LIVE | Transnet's former engineer back in state capture hot seat

Former Transnet electrical engineer Francis Callard is back in the state capture inquiry hot seat.

During his testimony in May, Callard revealed that an increase of about R1bn in the cost of 100 locomotives from China South Rail (CSR) was "excessive and difficult to justify".

Callard said he was instructed in April 2014 by Transnet's then executive finance manager Yousuf Laher to draft a memorandum for the increase in the estimated total costs payable to the Chinese consortium from R3.8bn to R4.8bn.

This was for the controversial purchase of 100 electric locomotives.

The commission is also set to hear testimony from command centre flight post officer Thabo Ntshisi relating to the April 2013 Gupta flight landing at Waterkloof Air Force Base in Tshwane.

In recorded conversations between the former head of state protocol, Bruce Koloane, and senior defence officials, including Ntshisi, Koloane is heard saying that then transport minister Ben Martins and minister of defence Nosiviwe Mapisa-Nqakula were aware of the flight.