Decca on Eastern Air Lines DC-9
Eastern Air Lines fitted its Air Shuttle DC-9's with Decca Nav around 1968. It was called "Sky Guide". Main problem seemed to be the number of cartridges needed. Also idea was to bypass airways going more directly - In crowded Northeast corridor from Boston to New York to DCA area it was not really practical. I believe it was also fitted to the French STOL demonstrator we flew for a while with Scott Crossfield as Project Manager.