Was reviewing the Cessna 175 TC sheet. It seems Cessna built only one R172J model, listed as s/n P17257189, which is one s/n beyond the last P172C. This airplane is on the current register as N1909F as a 1963 model, but with an airworthiness issue of 1974. The TC sheet also shows this airplane as a 1974 model. Cessna Service News Letter (SNL94-6), page 17, lists the R172J as s/n R1720559 and later became s/n 680. It also lists the airplane as a 1973 model as the R172J proto-type.
Anyone have any info on the anomaly ?