Tractor-drawn aerials (TDAs) were prevalent many years ago in fire department fleets, but fell out of favor to rear-mount and midmount straight-frame aerials.
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By Alan M. Petrillo
Yet today, TDAs continue to be used by many departments for a variety of reasons, including maneuverability, storage capacity, ground ladder carrying ability, and faster setup time at a fire scene.
Advantages
Tim Smits, senior sales manager of fleet management for Pierce Manufacturing Inc., says a TDA is one of the most versatile pieces of aerial apparatus in a fire department's arsenal of vehicles. "A TDA has excellent maneuverability, and with an experienced crew, there's virtually no place you can't take the TDA because of its fifth wheel articulation and the ability to steer the rear of the apparatus around obstacles," he says.
Often, the area covered by a TDA's ladder is greater than a department could achieve with a straight-frame rear-mount ladder. "Brevard County (FL) has a 100-foot Pierce TDA that they took out on a training scenario at a hotel property that had an enclosed garage in front of the structure," Smits says. "There was only a two-car-width area in front where you couldn't position a rear-mount, so they maneuvered their TDA in so they could cover the whole front of the structure. They parked the TDA in the center and were able to hit every floor and balcony, and when they tried it with the rear-mount backed in as close as it could get, they only could hit one quarter of the structure."
Dave Perkins, aerial specialist for E-ONE, points out that besides maneuverability, carrying larger complements of ground ladders and having more compartmentation are big advantages of a TDA compared with a straight-frame aerial ladder. "Maneuverability seems to be the biggest benefit of a TDA over even a single-axle straight-frame ladder," Perkins says, "but another thing we're seeing propel fire departments toward TDAs is they are more concerned about carrying more ground ladders. In addition, there's more cubic feet of compartmentation, so departments are able to use the TDA as a specialized truck company and have its hazmat or water rescue components on the vehicle."
Pete Hoherchak, aerial products manager for KME, agrees with Smits's and Perkins's assessments. "With a TDA, the purpose of steering from the rear is maneuverability where the vehicle is able to get around in tight city streets," Hoherchak says. "Where the tractor goes, the tiller can follow."
Compartmentation is another critical benefit of a TDA, he adds. "A typical rear-mount ladder has a minimum allowance of 2,500 pounds of equipment," Hoherchak notes. "On a TDA, it's the same minimum requirement by the National Fire Protection Association (NFPA), but most departments are able to put between 5,000 and 8,000 pounds of equipment on the vehicle because of the space available and the fact that the TDA can handle it."
On the ground ladder issue, Hoherchak says a typical straight-frame aerial ladder will carry 115 feet of ground ladders, while a TDA will easily carry more than 200 feet of ground ladders.
Disadvantages
Chuck Glagola, aerial sales manager for Smeal Fire Apparatus, notes that TDA disadvantages includ