I read a thingy put together by a Lockheed dude saying the A model involved was ex military and had been retired in/around '77 and brought out of "retirement" for fire bombing in the 90's. It had not had any work done on the center wing box. A models were known to have problems with their wings, hence why they re-engineered for the E,H,J etc. Looks like it's been re-engined as the props are 4 bladers.
PAF
