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Old 21st May 2018, 03:29
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ImbracableCrunk
 
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Originally Posted by RAT 5
Does the VNAV descent profile consider that we're flying directly to the FI, therefore we're high?

Indeed, because from your description you have told the FMC you are flying a shortened route. If you were on VNAVPTH at the time of the change then informing the FMC you are flying s shorter distance will cause VNAV to calculate you are high; but you may not be and so it needs good SA to manage your descent path and remain in idle and on a sensible path.
Didn't last time this question came up (and the time before that) we decided that the VNAV PATH transposes you laterally to the final approach course but at your current altitude? (i.e. If you are 5 miles direct to the FAF and 4 miles to the final approach course, VNAV thinks you're 3 miles 3-4-5 triangle)
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