It’s a typical warm summer morning in northern Arizona, but inside the engine bays at the Tusayan Fire Department, the air is heavier, warmer and smells strongly of diesel fuel. Fire Chief Greg Brush places the palm of his hand on the hood of Engine 51, the department’s all-purpose utility apparatus. Today, it’s running. Tomorrow, he’s not so sure. The truck, a 2002 Ford F550, is the department’s workhorse. It’s the first unit dispatched on most calls – including medical calls, structure fires, smaller wildland fires and traffic accidents – from Grand Canyon all the way to Valle. Brush said the truck’s age, appearance and even mileage aren’t that troubling, at a glance. But take a look underneath the hood, both figuratively and literally, and you’ll see a host of problems that need to be solved.