With a 40 ton GCW the Actros can move a very large firefighting water tank, as illustrated here. As this may operate exclusively on airport grounds, it may well exceed the nominal capacity of 40 tons, possibly indicated by this really enormous trailer tank…..Having a unit like this to supply the crash trucks almost certainly beats having them shuttle back and forth if they need to handle a major fuel-fed aircraft fire.
It looks like it is equipped to lay a foam carpet going by the bar and nozzles at the rear.
Added by Bristol Bob on 06 November 2022.
Looking at the approximate size of that tank trailer, it could well contain an estimated 25,000 to 30,000 litres or more of water! No doubt its has a primary role for use for runway carpeting, but also - if circumstances require - as a “nurse” tanker for crash trucks, which usually have a much more limited on board supply of water and foam compound. An additional tactic for this type of tanker would be to isolate the fire ground in the event if a major surface fuel spill, to protect the crash trucks as they zero in on the aircraft which is involved.
Added by Rob Johnson on 05 November 2022.