blue up
9th Dec 2012, 13:14
A quick question for the techie types.
On the 757 Pegasus (or Honeywell, I guess) how is distance to go calculated when a hold is in the FMC as either the next waypoint or the next-but-one? I flew into Alicante last week and the DTG was up and down with recalculations. I'm guessing it takes a simple view of the hold until it becomes the active waypoint whereupon it recalcs to take into effect the actual wind? Approaching the hold I then deleted the hold but there were still a couple more changes to the dtg before waypoint passage. The confusion (both mine and, perhaps, the FMC) was sufficient to go back to measuring the dtg with the width of my fingers.
It would be handy to know how the FMC does it. Nothing in the FMC handbook or our laptop tech pages.
I'm so glad that fingers don't require batteries.
PS Is that where the phrase "Rule of thumb" comes from???
On the 757 Pegasus (or Honeywell, I guess) how is distance to go calculated when a hold is in the FMC as either the next waypoint or the next-but-one? I flew into Alicante last week and the DTG was up and down with recalculations. I'm guessing it takes a simple view of the hold until it becomes the active waypoint whereupon it recalcs to take into effect the actual wind? Approaching the hold I then deleted the hold but there were still a couple more changes to the dtg before waypoint passage. The confusion (both mine and, perhaps, the FMC) was sufficient to go back to measuring the dtg with the width of my fingers.
It would be handy to know how the FMC does it. Nothing in the FMC handbook or our laptop tech pages.
I'm so glad that fingers don't require batteries.
PS Is that where the phrase "Rule of thumb" comes from???