Only two YA-9A prototypes were built by Northrop Aviation, serial numbers 71-1367 and 71-1368. Together they completed 123 flights, totaling 146.0 flight hours during the ground attack aircraft selection. Unfortunately for the A-9, its competitor in the ground attack selection was the now legendary Fairchild Republic A-10 Thunderbolt II. Possibly the greatest ground attack aircraft ever designed. The March Field Air Museum received its YA-9A in 1981 as a loan from the US Air Force.
[marchfield.org]
Photo by Craig Maas on Thursday, August 11, 1994 at the March Air Force Base, Riverside, CA.