STAR constraints decoded (or displayed) incorrectly

[skiselkov]

While flying on the US west coast I noticed that frequently VNAV constraints on STARs are represented incorrectly in the FMC, necessitating a manual update (which is also kinda buggy, but whatever). For example, KSFO's SERFR2 RNAV STAR should be:

• SERFR
• NRRLI, 280/FL200A  <- represented correctly on LEGS page
• WWAVS, 280/19000-15000  <- represented incorrectly as 280/FL190A
• EPICK, 280/15000-10000  <- represented incorrectly as 280/15000A
• (remainder of STAR correct)

In general, whenever there's a "below" or "above & below" constraint, it gets incorrectly translated to just "above". Moreover, trying to change WWAVS to "/FL190B" just changes it to "/FL190" with no more details (and the FMC attempts to fly through it at exactly FL190). I suspect the FMC is incorrectly decoding the Navigraph database, as it contains these kinds of entries:

<Star_Waypoint ID="3">
  <Name>WWAVS</Name>
  <Type>Normal</Type>
  <Latitude>36.741531</Latitude>
  <Longitude>-121.894234</Longitude>
  <Speed>280</Speed>
  <Altitude>19000</Altitude>
  <AltitudeCons>15000</AltitudeCons>
  <AltitudeRestriction>above</AltitudeRestriction>
  <Flytype>Fly-by</Flytype>
  <BankLimit>25</BankLimit>
  <Sp_Turn>Auto</Sp_Turn>
</Star_Waypoint>

I suspect the FMC is simply interpreting the AltitudeRestriction value as always applying to the Altitude value and ignoring AltitudeCons. The NACO STAR chart for SERFR2 is available here.

[Litjan]

Thanks for the report - known issue and we are working on that!

Jan