I want to follow the OOSHN5 arrival route, but i have a few questions about it. How do i know what VS to use in between the WPTS? also what are the numbers under the altitudes with the *?
Maybe this can help you.
I believe you are to calculate your own VS and just have to meet the crossing restrictions.
Vertical Speeds are pilots discretion, meaning you can use whatever VS you deem needed to achieve the altitude at the point.
The OOSHN5 into KBOS is a “continuous descent arrival” meaning you’ll keep on adjusting down to hit at/between targets. A good way to do this is by using In Flight Assistant’s VNAV feature (comes with the GPWS in app purchase-only on iOS as of now iirc) If you can’t use In Flight Assistant to get your speeds and altitudes setup-you can do some simple math if you have a calculator or other device handy. If you’re between 14000/9000 at OOSHN (let’s say 13000’ for the purposes of this) and at 250kt going for 22L (Via GRGIO BRGIT ADDAA LEEZI) and you’ve got 2:30 time to go to GRGIO where you need to be under 9000 you’ll need a VS of -1600 or so to get under 9K at GRGIO. With that in mind, you HAVE to be AT 7000 at BRGIT.
I find that when I need to calculate or input into VNAV-that it’s better to calculate/input the VNAV to the HARD limits-the ones that have two lines above/below them. So say you’re at 13K/250kt at OOSHN-and you’ve got 4:45 time to BRGIT and you need to get down to 7K at BRGIT.
The math on that is 6000/4.75=VS -1263
The IFA VNAV feature is waypoint for waypoint-there’s currently no “look ahead” or profile calculation as it were. If you’ve got two waypoints that are setup close to each other and you put an altitude in-the IFA VNAV will tank you down at -5000 max in an attempt to get there.
The OOSHN is a fairly gentle descent profile save the 4.7 mile run from BRGIT to ADDAA where you’ll slow to 220kt and descend 1000’ in 4.7nm as you’re slowing.
I’ll put a video on this up later on today. I’ve not flown the OOSHN in a while-I mostly use the ROBUC3 and JFUND2 with my VA. Any questions feel free to ask here or in a DM
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