As far as four-axle airport crash tenders are concerned, it all began with the P-15. Oshkosh developed this vehicle, designated A/S 32P-15, on behalf of the government. Based on this basic concept, numerous civilian variants followed later, designated M-12, M-15 and M-23. These designations meant:
M-12: 3,000 gallons, 12,000 liters of water
M-15: 4,000 gallons, 15,000 liters of water
M-23: 6,000 gallons, 23,000 liters of water
By the time of development in 1977, seven commercial versions had already been built and delivered to customers. At the same time, further units were in assembly or testing.
