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How to edit strange altitudes?


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I'm sure this is an easy fix, but I can't find it. As you can see, PFPX wants the aircraft to climb to just below 20,000 feet for a microsecond (actually it's 4 minutes), then descend back down to 16,000 feet for another microsecond, and then climb up to FL310.


On the OFP, the initial cruise altitude (the value of <&InitCruiseAlt>) is 17,999 feet. Clearly odd.


To fix this, first I put in a Min Alt/FL of FL250 and hit Compute again, but I get the same result: 4 minutes of level cruise at 17,999 feet followed by a descent. So then I next looked for a way to edit only the altitudes in the advanced route editor and I'm not seeing it.


One thing I noticed were that the initial waypoints were on a low-altitude Victor airway. So I hit the button that said Upper Airways, and still got the same result. Then I removed the airways between the initial waypoints and made each waypoint just DCT to the next. Still the same result.


Any suggestions?


Thanks for your help.




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  • Will C changed the title to How to edit strange altitudes?



I usually play around with desired flight levels on the "Advanced" tab. I know the general FL idea and conducting test-and-trail, I find proper fit between FL and fuel consumption. There you can choose OPT, MAX, or a direct entry (helps with flights in China RVSM).


For NAT crossing (but not only for that) you can play around with Fixed Speed as well.




Easy fix may be selected "Open MAX" and "Open OPT" flight level 




Usually after these edits, my FLs are set straight. Also, make sure that the route allows for certain FLs. For example in Italy, direct routing is used above FL305 (that is my experience; happy to be corrected).




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Thank you Andrej, that seems to work. Can you (or someone else) check my workflow and let me know if I'm doing this in the best way?


1. "Compute" the flight.

2. Check the OFP, note that the altitude needs fixing (Init Alt = 17999 feet, there is a descent immediately after departure, etc.).

3. Note the preferred initial cruise altitude (FL310).

4. Note the first waypoint past the altitude issues (e.g. CGT).

5. Hit Re-Plan.

6. Go to Advanced > Speed/Altitude/Holding, enter initial waypoint under "From," enter first waypoint past the altitude issues under "To", and enter the preferred initial cruise altitude under "Fixed Altitude/FL." For this flight, this pane now looks like the illustration below:





7. Hit "Compute" again.

8. Now the problematic section has been smoothed over, and the aircraft climbs to the initial cruise altitude without issues, and continues to climb on schedule without further manual inputs, see below (compare this illustration to the one in the original post):





Operationally, this solves my problem. But I'm wondering if this is the best workflow? Is there a more efficient or a more preferred way to get to the same result?










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what I would do is select RAYNR in the field below "Waypoint" and type 310 into the "Altitude/FL" field. This would give you FL310 from very first waypoint.

What is your step altitude at what waypoint? Subsequent step climbs seem to take a "benefit" from enroute winds. However, sometimes, step up at later stage provides you with a better fuel management. After VAULT, there are too frequent change for my liking.


Once you selected another waypoint, where you wish to step climb, you can then manually select desired step altitude (eg. 330, 350 -> for respective flight level).

Here is a sample of my "Advanced Tab" after I created flight from EDDK to KMIA.



During my flight planning process, "From Waypoint" and "To Waypoint" option is used for speed (mostly). I don't tend to utilize Fixed Altitude option here.


This way, I don't have to deal with initial lower FLs (e.g. FL240) on departure from EDDK (as specific low level airways are designed for it).

Then I selected initially calculated step climb points with desired FL change. Sometimes, when I play around with this, I can reduce fuel consumption. Today, PFPX did very good job. :)

Hope this helps.




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Thanks, that's helpful. I remember a real-life dispatcher once said (on another aviation forum) that the real-life professional flight-planning software sometimes got too zealous about changing altitudes up and down to "chase tailwinds." He said that he tended to smooth things out into orderly step climbs, since that was what was most compatible with ATC clearances anyway.



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