The 19 was equipped with two single lung air pumps, one mounted on each side at one time during her career on the McCloud. The two pipes in front of the stack were the exhausts for these pumps. McCloud would later replace the two pumps with the current cross-compound compressor. The shield was what the spark arrestor would rest against when the it was tipped to the side to allow better drafting of the engine when firing up or create clearance for moving through door ways.