FMC SIDS and STARS MEA considerations

[kmw510 0]

When double checking the programming of the FMC for the SIDS and STARS I can see where the program almost always enters hard altitude and speed requirements, however, it is difficult to tell whether or not the segment MEAs are being considered. For the most part it appears that the predicted altitudes do not violate the MEAs but I am unsure as to whether the FMC actually considered the MEAs since the numbers are shown as predicted rather than required values. In only a few cases have I substituted a required altitude to cover the MEA shown on the charts but don't know if this was a mistake in the programming of the STAR or SID or where the FMC just doesn't consider MEAs.

 

Kevin W

[Spin737 102]

The FMC doesn't consider MEAs, but the SID does. Don't make things too complicated

[kmw510 0]

The FMC doesn't consider MEAs, but the SID does. Don't make things too complicated

Im not sure I understand your statement. I understand that the SID charts show MEAs in segments where applicable, however, Im not sure that the airinc data loaded into the FMC when you select that SID contains those altitude constraints. I can see where altitude constraints defined on the chart at fixes show up as altitude constraints in bold in the FMC but don't see corresponding bold entries for any MEAs

 

Kevin W

[Spin737 102]

 

 

In only a few cases have I substituted a required altitude to cover the MEA shown on the charts but don't know if this was a mistake in the programming of the STAR or SID or where the FMC just doesn't consider MEAs.

 

Im not sure I understand your statement. I understand that the SID charts show MEAs in segments where applicable, however, Im not sure that the airinc data loaded into the FMC when you select that SID contains those altitude constraints. I can see where altitude constraints defined on the chart at fixes show up as altitude constraints in bold in the FMC but don't see corresponding bold entries for any MEAs

 

Kevin W

RW, I've never seen anyone check against those MEAs unless there was an issue with needing a lower altitude because of a malfunction, or whatnot. That's not to say what you're asking isn't correct.

 

I'd say if you're on the STAR or SID, those routes have already been flight-checked and you shouldn't be worrying about the MEAs if you are on the route.

 

I don't have a reference for you to refer to, sorry.

[ubersu 78]

Any hard constraints in a SID or STAR have been designed for and checked against terrain and any applicable other constraints.  Any other altitudes shown do take MEA into account.

 

DJ