NP
Of course no excuse. However given the rate of descent earlier in the approach and the residual thrust of the engines at idle, thrust was not needed till 500'.
No one noticed the AT mode. Everyone just expected the thrust to come on. In AT hold this was never going to happen. At least on the 777 the levers move so the PF should have realised the power was not going to come up. On the Bus the levers do not move.
Stabilised approach also includes a reasonable thrust amount at a given height usually 1000' and at the latest 500'.
This aircraft crashed because it was effectively a glider and glided into the sea wall.