SimBrief and its recommended step climbs

[Romano Lara]

Case: I noticed that the recommended step climbs is sometimes wrong for a particular direction.

 

Example route: (RPLL to KJFK // Eastbound)

 

CAB2R CAB N884 ALBAX Y533 AZAMA Y57 YULIA/N0492F310 Y57 BUNGU Y81 SYOYU Y809 KAGIS A590 POXED/N0478F320 A590 POWAL/N0482F330 A590 PINTT/N0482F340* A590 HAMND/N0469F330 TED J511 GKN/N0477F350 NCA14 YNE J542 POPLR J513 YRL/N0484F370 J513 YQT TVC YXU JHW J70 LVZ LENDY6

 

 

Now I checked my en-route charts and saw no specifics as to why I should be on an even level for this particular point. I was wondering if this was just a glitch on SimBrief's end or there is a bigger reasoning behind it that happens in the real world?

[nebojsa milosavljevic]

Interesting.There has to be a reason.Have you asked at simbrief forum.

 

nebojsa

[Simon Kelsey]

According to the Jeppesen Airway Manual:

 

EASTBOUND

 

a. Aircraft transitioning the NOPAC Route System eastbound to North America or Europe may use:

 

1. A590 at all times utilizing odd cardinal altitudes from FL190 to FL410 and FL300, FL320 and FL340.

 

Above FL410, altitudes will be [Mod - Happy Thoughts]igned as per ICAO Annex 2, Appendix 3b.

 

It would appear therefore that FL340 is a valid level on A590 eastbound and therefore works as a step climb (presumably the system calculated that either the aircraft was too heavy for FL350 at that point, or more likely the winds may have been more favourable at FL340).

 

The descent back to FL330 at HAMND would be for the same reason: FL340 presumably is not a level available eastbound on J511 so you would be forced to either FL330 or FL350 depending on weight and wind.

[Romano Lara]

Thanks Simon. Thought it had to be one of those things, but sadly I do not have an access to a Jeppesen Airway manual to cross check these things for my usual long hauls from Asia to North America and Europe. I will look around though, but thanks for pointing it out. Great help!