This time, I'm starting the second Anton deGama story, Black Ice.
The harpoon slammed into the sliding permafrost, getting no grip at all, and doing absolutely nothing to stop the crawler's descent. The craft lurched sideways again, methane mist snarling around the racing tracks. Anton keyed in to haul back the harpoon, and eased off on the throttle, hoping that slowing the engine might regain control of the sliding ground-craft. According to the manual, VauxHall-Douglas claimed the duranium-alloy heated tracks could maintain a secure grip whatever the surface, whatever the gradient, within reason. Presumably, Anton murmured to himself, VHD did not consider 30 degrees to be within reason.
The ammonia permafrost beneath the crawler was sliding faster, sending more mist and debris up around the cockpit, reducing visibility further. The vehicle had already slipped 80 metres down the hillside, and was gaining speed. More worryingly, according to the chart Titan-B had provided, there was a drop-off only a thousand metres below him. Anton had a shrewd suspicion that VHD's guarantee of the durability of the crawler would be invalidated by a 30 kilometre fall into one of Titan's justly-feared trenches.