P-3 Orion

    In August of 1957, the Chief of Naval Operations (CNO) issued Type Specification number 146; a requirement for a land-based ASW aircraft. The Lockheed Aircraft Corporation, already in the forefront of post WWII aircraft development and having already proven the merits of other aircraft such as the Hudson, Vega Ventura, Harpoon, and Neptune, decided to join the competition. Although the requirements of Type Specifications 146 were quite exacting, Lockheed believed the answer for a suitable aircraft could be found in its civilian liner, the L-188 Electra.