This aircraft was bailed from the USAF to Lockheed for use in Operation Hourglass, as part of the Electra program. Although the Allison 501D engine was proving reliable, Lockheed flew the aircraft for 30 days on a carefully planned 'airline' schedule in order to test its durability for commercial operations, which involved much longer operational days and multiple daily flight cycles, than the engine had thus far experienced in military use. Photo from Lockheed Aircraft Corp.

Converted from a civil CV340-36 in 1954 and seen on display at Lockbourne AFB, Ohio in May, 1956, still fitted with Allison YT-56-A3 engines and three bladed propellers. Later fitted with Allison 501-D13 and then 501-D26 engines. Re-designated CV770 in 1967 in civilian use. Registrations worn include N5511K (ntu), N454, N454X, N970L, N630V. Convereted to a CV580 in 9/79 as N600AB, and later N400AB and C-GKFY.