Originally Posted by
NewquayJacob
I was just surprised that scheduled IFR traffic at FL150 would be in receipt of a basic service.
It was just the way things were in those (happy) days. It happened all the time. It was known as Air Traffic Advisory Service. Most airlines & commercial operators flying routes which were not within the Controlled Airspace regime flew on more direct routings between departure & arrival points. Usually, they would work military radar units.