 Three AJ @-@ 2s were loaned to the National Aeronautics and Space Administration as weightlessness simulators from January 1960 to September 1964 . They were eventually destroyed during firefighting training . Three AJ @-@ 1s were purchased by AJ Air Tankers , Inc. in early 1960 for use as water bombers . Their turbojets were removed before the delivery flight to California , during which one aircraft crashed . The two surviving aircraft were fully modified for the role after delivery and could carry 2 @,@ 000 US gallons ( 7 @,@ 600 l ; 1 @,@ 700 imp gal ) of fire retardant . They first flew missions during the 1961 fire season . Another aircraft crashed on takeoff in September 1967 when an engine failed and the sole survivor only made a few more flights before it was scrapped in 1968 – 69 . 
