Going through my first type rating and I am a bit confused on the difference between VNAV PTH and VNAV SPD. Am I correct in saying that:
- in VNAV PTH the FMC will command pitch to mantain pitch and if required it will command the autothrottle to mantain FMC SPEED
- in VNAV SPD the FMC will retard the throttle levers to IDLE and mantain speed with pitch and will not attempt to stay on path similar to LVL CH
I do understand that the ideal descent path, provided forecast winds are correct, will result in a idle descent.