How is engine management being done without auto throttle during a VNAV approach?
Is the pilot continuously adjusting thrust levers (or power levers in the case of turbo prop) to maintain appropriate angle of attack, as the speed, decent rate and heading is controlled by the auto-pilot...?!!


In 747-100/200 operations at the two 747 carriers I flew for, if you chose to have the autopilot fly a coupled ILS approach and didn't have auto-throttle capability, the autopilot tracked the glideslope by changing the pitch of the aircraft. 

Personally, I never did this because I preferred to hand fly all approaches, but I watched others do it when I was the non-flying pilot, and they did indeed continually adjust the thrust levers as necessary to get the desired speed, just as we did when hand flying the approach.

In the 747 classics this wasn't hard. Initially you set the thrust levers to a fuel flow of 5,000 lbs/hr per engine, maybe a little less if very light, maybe a little more if heavy. Often that initial setting would give you the speed you wanted within a few knots and no further adjustment of the thrust levers would be necessary until starting into the flare. If it didn't, you adjusted as necessary, and with experience it took very little jockeying of the thrust levers.