What are your concerns? How will you attack with three Engines responding with two on each? What size line and where? Can you vertically ventilate? Where is the FLOW PATH?
What are your concerns here? When can you vent a TRUSS ROOF? What’s more dangerous; a Residential Truss roof or a Residential Truss floor?
Conserns as always would be if home is occupied as well as location of fire. Once location is known roof ventilation may be an option. Do to load that is on a floor those would be the trusses that are most liket to fail if a fire is below grade. Thus making an aggressive interior attack is crucial.
A rule I applied may times about truss is remember if you maybe should not be on it, you maybe should not be under it. Once you determined a significant collapse risk, such as fire damage to the trusses themselves not only would you not want to be on it you would not want to be under it.
A truss is a truss it can kill rapidly and will fail under fire exposure to its structural elements, crushed from above or burned from below as you fall trough, both scenarios kill and injury.
That being said if a truss is still structural sound due to low exposure or no exposure to fire, you may proceed with standard fire fighting tactics with an eye of caution to the truss problem and constant re-evaluation of the condition of the truss’ soundness.