On paper it makes great sense, I suppose. Why have a dedicated rescue when you can put that equipment on an Engine and get it to the scene in more-efficient manner and without the extra staffing required for an additional piece of apparatus?
However, what do you accomplish when you put the extrication equipment on an Engine but then have to send another Engine Company on the assignment to make up enough staffing to do the Engine and Rescue work? If you are a department that has widely dispersed apparatus you may actually be in worse shape than with some of your other options. It might make more sense to maintain the dedicated Rescue apparatus and cross-staff it to a Ladder Company or put the rescue equipment on the Ladder Company. Or, make sure your Rescue/Engine has a crew of at least (4) people so you don't have to assign an additional Engine unless the situation warrants it.
On a related note, Rescue/Engines responding to fires are a great indicator of the awareness of an agency. If you really must assign a Rescue/Engine to a fire as a Rescue, then if it arrives before the "real" Engines on the assignment, shouldn't that apparatus work as an Engine? This may violate some widely held beliefs, but the presence of a Rescue (especially if it's a Rescue/Engine) is not essential to the extinguishment of a structural fire. The work that a Rescue Company does at a Fire can be performed by other apparatus (and most likely will be, especially if the Rescue has a lengthy response time). If they are close enough to be helpful then by all means send them, but we probably need to be honest about what needs done on the scene of a fire and what company is likely to do it. Engine work, truck-work, a medic or two, water supply, and command are the bread and butter roles- those should be the priority, all else falls under "nice-to-have"
It all comes back to resource management and making sure we make the best possible decisions about how we use what we have. Getting caught up on the apparatus designations or reducing our resources in the process of trying to preserve them don't actually do the best good for the public or responders.
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Welcome to my site and thank you for reading. After many times thinking, if only I had a blog, well-- here we are. This blog will feature writings on a variety of topics from roadside food, to leadership in the fire service; politics; culture- gay, straight, and indifferent, my experiences in Ohio, New York and beyond; and much much more. It's my hope that you will find it interesting and that it stirs at least some thought and discussion. I am certain you wont always agree, but that is what its all about right? Oh and one more thing: The views expressed on this site are entirely my own. They do not reflect in anyway the views or positions of my employer.