ILS-tillvägagångssätt användes gemensamt under 1970 då jag fick mitt instrumentbetyg. Det normala (Cat I) taket var 200 meter. Så, ja, en 707 skulle ha kunnat landa med ett 300 meter molntak på 70-talet.
Jag kollade Wikipedia och hittade historikposten nedan:
Tests of the ILS system began in 1929 in the United States.[14] A basic system, fully operative, was introduced in 1932 at at Berlin-Tempelhof Central Airport (Germany) named LFF or "Lorenz beam" due its inventor, the C. Lorenz AG company. The Civil Aeronautics Administration (CAA) authorized installation of the system in 1941 at six locations. The first landing of a scheduled U.S. passenger airliner using ILS was on January 26, 1938, when a Pennsylvania Central Airlines Boeing 247D flew from Washington, D.C., to Pittsburgh, Pennsylvania, and landed in a snowstorm using only the Instrument Landing System.[15] The first fully automatic landing using ILS occurred in March 1964 at Bedford Airport in UK.[16]
Den CAA som avses i citatet var föregångaren till den amerikanska FAA.