Issue with Cruise Level Assignment in Rostov (URRV) FIR

SimBrief Dispatch
1

Hello everyone,

I’m writing to report an issue with cruise level assignment in the Rostov (URRV) FIR when using the SimBrief dispatch system.

It appears that SimBrief does not currently account for published ATS route restrictions related to semi-circular cruising levels in this specific FIR — particularly on segments where the magnetic track frequently changes between eastern and western directions.

Example routes: B105 and R807 within the URRV FIR.
Relevant NOTAMs (for reference): U0181/26, U0182/26, U0186/26 — these specify mandatory odd/even cruising levels regardless of the aircraft’s actual magnetic track. In some cases, they even impose unidirectional level ranges.

Currently, SimBrief applies standard hemispheric rules based on magnetic course. This leads to incorrect level assignments on these segments (e.g., assigning FL340 when the route requires FL350), unless manually overridden in the flight plan.

This creates a discrepancy between the filed flight plan and the actual ATS requirements in the Rostov FIR.

It would be very helpful if SimBrief could take into account these local FIR-specific restrictions during route validation and level selection.

Happy to provide more details or specific route examples if needed.

Thanks for your great work on SimBrief!

2

Hi, we replied to your email last week but it seems your inbox rejected the reply.

I will re-paste the reply here:

Hi, we have checked the airways in your example (B105 and R807) and they seem to be planned correctly.

Using B105 as an example, the following NOTAM establishes the airway (U0173/26):

ATS RTE B105 ESTABLISHED:

CRP ABAGI (534037N 0424036E) - NCRP PELNE (530811N 0430351E),
TR 145DEG MAG, DIST 65.4KM, LOWER/UPPER LIMITS FL135/FL540,
DIRECTION OF CRUISING LVL: ODD.

NCRP PELNE - CRP NIMTA (510934N 0442809E),
TR 145/326DEG MAG, DIST 240.1KM, LOWER/UPPER LIMITS
FL135/FL540, DIRECTION OF CRUISING LVL: ODD,

CRP NIMTA - CRP NATIT (493406N 0441927E), TR 173/354 DEG MAG,
DIST 177.3KM, LOWER/UPPER LIMITS FL095/FL540, DIRECTION OF
CRUISING LVL: EVEN,

CRP NATIT (493406N 0441927E) - CRP VOLGOGRAD/GUMRAK VORDME (WGD)
(484651N 0442037E), TR 169/350 DEG MAG, DIST 87.6 KM,
LOWER/UPPER LIMITS FL095/FL540,
DIRECTION OF CRUISING LVL: EVEN.

This indicates that for the segment ABAGI-PELNE-NIMTA, cruising levels should be ODD. And for the segment NIMTA-NATIT-WGD, levels should be EVEN. The NOTAMs U0181/26, U0182/26, U0186/26 also indicate the same odd/even levels before and after NIMTA.

For the flight UUEE-URWI in SimBrief, which uses B105, SimBrief plans:

K0824F390 TOGMO3J TOGMO DCT ABAGI B105 NIMTA/K0824F380 B105 WGD G481 TONGI/K0830F370 G481 BAGON BAGON1E

Which is in accordance with the NOTAM as far as we can see (odd level until NIMTA, then even level).

Note that you sometimes must enable the “Stepclimbs” option for airway restrictions to be planned correctly. Make sure to enable this option during your testing.

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Maybe there are some cases in SimBrief which don’t follow the NOTAMs, but B105 and R807 seem correct at least.

Best regards,

3

Dear SimBrief Support Team,
Thank you for your detailed response and for checking the B105 and R807 airways. I appreciate the clarification about the Stepclimbs option, and I will ensure it is enabled during testing.
However, I would like to provide a real-world example where SimBrief currently assigns incorrect cruising levels that directly contradict active NOTAMs in the Rostov FIR (URRV). For example route SOCHI(URSS)-KAZAN(UWKD)

The SimBrief-Generated Route:

URSS/24 K0861F350 IRGI1T IRGID A944 GUBOR G487 ERSAR DCT BEMES R227 KZ DCT GORNU/K0854F360 B945 UP N50 MOLED/K0856F370 R807 UROBO P135 DAFOS T789 SONUM SONU1S UWKD/11

So, according to NOTAM U0181/26 (and similar U0182/26, U0186/26), which establish the ONLY permitted routes for departure from Sochi (URSS) in an easterly direction, the segment from ERSAR through BEMES to TUVGI (and onward) must be flown using ONLY odd cruising levels (CRUISING LVL ODD WI FL290-530). The same restriction applies throughout the subsequent eastbound unidirectional flow described in NOTAM U0164/26.
However, in the SimBrief-generated route:
The initial segment is planned at FL350 (odd – correct).
After GORNU, SimBrief steps up to FL360 (even – incorrect).
After MOLED, SimBrief steps up again to FL370 (odd – correct again).
This fluctuation between odd and even levels violates the NOTAM requirement for a continuous odd level throughout the entire eastbound segment within the URRV FIR. The even level at FL360 is not permitted on this route under current restrictions.

oddexample.png
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Another Example – Return Flight (Westbound):

UWKD/11 K0854F340 SONU1G SONUM T789 OGRER DCT UROBO/K0857F350 DCT SL N50 LIDUS DCT AST/K0856F340 DCT AMKOL DCT GOTIK DCT MEMZA DCT BINOL BINO1K URSS/02

For the westbound return leg, upon entering the Rostov FIR (specifically on segments leading to and through BINOL), NOTAM U0164/26 requires ONLY even cruising levels for the westbound unidirectional flow. However, SimBrief assigns a mix of odd and even levels (FL340, FL330, FL350, FL340) as it steps through the route, which does not comply with the requirement for a continuous even level.

evenexanple.png
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While B105 and R807 may be handled correctly when used in isolation, the more complex routing through the URRV FIR, involving multiple airways and step climbs, reveals a limitation. SimBrief appears to apply standard hemispheric rules at each segment based on magnetic track, rather than enforcing the continuous odd/even level requirement mandated by NOTAMs for the entire eastbound or westbound flow within this specific FIR.
It would be extremely helpful if SimBrief could recognize these flow-based restrictions and enforce a consistent odd or even level across the entire portion of the route that falls within the restricted airspace, regardless of intermediate step climbs or magnetic track variations.

I will attach a file that contains the complete set of NOTAMs related to this situation.

Thank you again for your attention to this matter. Please let me know if you need further details.
Best regards,
Tikhon Mikhalev

(attachments)

NOTAMs.txt (18 KB)

4

It sounds like you are asking SimBrief to automatically parse the latest NOTAMs at any given time and extract any applicable routings (or route portions) and directional levels on a per-flight basis.

This is an extremely complicated task and not likely to be added any time soon, if ever. Even most real-world multi-million dollar flight planning software cannot do this automatically, in most cases it requires human validation and manual entry by trained dispatchers who have intimate knowledge of their region of the world.

Also, just to clarify, SimBrief does not simply apply “standard hemispheric rules at each segment based on magnetic track”. The AIRAC data contains different cruise rules for each FIR, and often even different rules for specific airways. This means that if ever these “NOTAM rules” become permanent and are included in the AIRAC data by our supplier, SimBrief should begin following them. Perhaps this will happen in a future cycle, but for now we are not able to support such temporary NOTAM rules I’m afraid.

Best regards,

5

Thank you for the clarification. I appreciate you explaining how the system handles cruising levels. I’ll keep an eye on future AIRAC cycles for any permanent changes.

Best regards,