Questions about the DAL and UAL '18 OFP formats

DAL:
One thing I’ve noticed on the Plan Summary page is that I don’t think the WINDS field adds an extra digit if it’s a 3-digit wind. If you have like 110 knot winds at cruise, you might see something like 25110 in the wind, and so does that mean it’s 10 knots at 251, or is it 110 knots at 25something and it’s dropping a digit off the heading?

UAL '18:
It’s a little unclear to me how to get the actual average cruise winds. In the header on page 1 of the OFP There is a line that stars WIND. I did a test flight plan in this format today and the full line was

 WIND   060000 060600   01:44/00:08E        VRT 01 RTNG 01 RLSE 03

and I have no idea how to interpret “060000 060600”. Further down the page in the Routing section you have “WC H28” on this example I generated, which I assume is the wind component of H28, but on something like an Airbus you’re going to need the wind speed and heading, and I can’t find that in this format anywhere.

Also, is the ISA and tropopause given anywhere in this format?

Thanks!

Hi,

“25110” means 250 degrees at 110 kts. A few layouts use this wind format actually, not just DAL. AAL and BAW come to mind.

I don’t believe the average cruise winds are included anywhere in the UAL '18 format. Not sure what their procedures are for entering the winds into the FMS, but in the Airbus you should be able to enter the winds as a headwind/tailwind component on the INIT B page if you choose. Though the recommended procedure is normally to input the winds at each individual waypoint (which can be found on the “Forecast Winds and Temp Summary” page), rather than using average winds, so that might be what they do instead.

In the UAL '18 header, the WIND 060000 060600 line actually indicates the wind forecast validity time used for planning. So in this case, the 6th (of August) at 00:00 UTC until the 6th at 06:00 UTC.

Finally, for the ISA and tropopause height, look for the “FMS INIT LOAD” section on the first page. The ISA and TROP should be a few lines below that, “P10” and “F333” in the example below:

FMS INIT LOAD
KACY/KATL
ARPT REF POINT N3927.5 W07434.6
F380/M47 (P10)  TROP  F333
TOC BAL+5NM

Best regards,

Thank you! One clarifying question, you say 25110 would be 110 knots at 250, but what if the winds were 10 knots at 251 degrees? Would they round the bearing down to 250 to make it 25010? That seems like a system that is going to routinely introduce error, which if that is indeed how those formats are done is beyond SimBrief’s control, you just seem knowledgeable about them.

Yeah they always round the direction to the closest 10th degree. Even if the winds are less than 100 kts, the direction is still only afforded 2 digits. So winds 251 at 10 would be shown as “25010”.

While it is a bit less precise, my feeling is that it wouldn’t result in any noticeable error. In any case, wind forecasts are frequently off by ~10 degrees when compared to actual in-flight winds. And by rounding the direction to the closest 10th degree, the most they would be off by in the OFP is ±5 degrees.

Best regards,

Thanks!

One follow up. I just generated the following example OFP:
image

You can see that the OFP was printed at 0322z on 12 AUG 21, but that WIND line you explained to me, if I’m reading it correctly, has a valid time of 0600z to 1200z on the 11th – how does that work?

When you entered the flight options for this flight, you actually had the departure time set to August 11th at 3:33, instead of August 12th:

So it generated a flight based on yesterday’s winds. :slight_smile:

Ah ha, so I did. Thanks!

This topic was automatically closed 2 days after the last reply. New replies are no longer allowed.