The first A-12, known as Article 121, was built and ground tested in Burbank during January and February 1962. Because the aircraft was too secret to fly to the test site and too large to carry on a cargo plane, it had to be trucked.
Article 123 was lost on 24 May 1963 during a low-altitude, subsonic flight to test an inertial navigation system.
With a faulty fuel gauge, CIA Pilot Walt Ray was on final to Groom Lake, NV, when the A-12 ran out of fuel. Walt Ray ejected from the aircraft, he faile to seperate from the ejection seat and was killed when he landed in seat.
The newly-installed SAS (Stability Augmentation System) had the yaw and pitch gyros wired backwards, causing the airplane to lose complete control just seconds after takeoff from Groom Dry Lake;
While on a FCF (Functional Check Flight) CIA Pilot Jack Weeks and the A-12 disappered, No trace was ever found of pilot or aircraft.