Just browsed by this thread and wanted to pass on my thoughts:
The first category a helicopter was the S61, which was certified in the early 1960s. It was a CAM 7 certified helicopter, the predecessor to FAR Part 29, and so it was certified to airline transport requirements. This meant that the FAA had to synthesize requirements that were similar to the Part 25 airplane airline transport requirements. Part 25 requirements had engine failure on takeoff, rotation speeds, accelerate stop distances, and takeoff distances. All were specified using careful flight test procedures.
The Category A procedures used for the S61 family included a runway procedure and elevated heliport procedures. The elevated heliport procedures were used for the very first transport operations between the Pan Am building in downtown New York and the New York world's fair Pavilion in Flushing Meadows, New York. The test pilots who performed these procedures told tales of flying over 1000 takeoffs and landings as part of the certification effort. I met Jim Plackis the other day, he was the FAA test pilot on these operations.
The S61 was the precursor to all these Category A operations that are now standard for part 29 helicopters.
