In days long ago, if you did not work for an Airline you were issued with a Senior Commercial Pilots Licence, with a Command Endorsement and a Command Instrument Rating, the Co- Pilot was issued with a Co- Pilot endorsement and Co- Pilot Instrument rating.
The memory is fading, but I'll have a go. (A little disjointed and long winded, but hopefully you'll get the idea)
If you worked for an airline (there were only two originally), the Captain had a First Class Instrument Rating and an ATPL. The FO had a Second Class Instrument Rating and a Second Class ATPL.
Remember, Airlines wanted to keep GA pilots in their place, and they didn't want GA pilots having equivalent qualifications to them! We got lumbered with the Class One, Two, Three, and Four Instrument Rating for aircraft less than 12500 lbs.
The whole reason for the First Class / Second Class IR, and First Class / Second Class Endorsement was to keep the airline pilots of the day up on a pedestal, and separated from the rest of us.
If you flew an aircraft less than 12500 lbs, you only needed a Class One IR, and a CPL.
If you flew for Bush Pilots for example, at that time, one of the few operators that had aircraft above 12500 lbs (DC3) flying RPT runs, the Captain needed a SCPL and a First Class IR, (there were exceptions!), the FO needed a CPL and a Second Class IR. Because Bushies didn't have an Airline License, the pilot's couldn't get an ATPL. That was for Airline Pilots only!
Strangely enough, a Second Class IR did not allow you to exercise the privileges of a Class One.
It was a very messy system. Finally all that was done away with, and more operators were welcomed into the Airline fold.
The Command / CoPilot Endorsement was introduced, along with the Command / Copilot Instrument Rating.
.....and we all lived happily ever after.
Please feel free to correct any misrepresentations! Years in GA can skew one's perception!
