737 NG altitude constraints

[dcman]

Setting descent altitude constraints on the legs page is a pretty straightforward process: ie. 250/FL200, 120A, 120B. However, if an arrival incorporates a crossing between two altitudes, say below 16,000/above 12,000, how is that coded so the FMC will accept it manually?

This question is related to the 737NG Smith FMC.

THANKS

[framer]

I've never come across such a requirement. You could just enter a hard altitude of say...14,000ft

[Capt Chambo]

Input 120A/160B in the legs page.

It's in the VNAV section of your FCOM in the section SPEED/ALTITUDE constraints.

[ajd1]

How about 250/160B120A

[ajd1]

The reference for the above, in my FCOM, is 11.31.21 "Altitude restrictions that are between two altitudes are displayed with the lower limit first, followed by a suffix letter A, then the upper limit, followed by a suffix letter B (example: 220A240B).

So if that's correct my first post on the subject should have read 250/120A160B.

[STBYRUD]

If you had to do it you could conceivably create a new waypoint short of the one with the constraint (ABC-0.1) and give that the other constraint... That'd be a little excessive though I guess.

[dcman]

Thanks for all responses. I mistakenly thought there was a method to manually code it. The situation arose descending off airway with this type of altitude constraint based on DME alone (MMMX).

[Turbavykas]

Can you just add a fixed constraint in the middle? :)