Force a/c to overfly a waypoint

[tstiegler 0]

Hi,I noticed the behavior in the 747 but I think it's the same with the 737: The FMC tends to "shortcut" corners in the flight plan. Most time this is very welcome but sometimes I want to force the a/c to overfly a waypoint in any case (mostly during approach). Is there a way to program a waypoint in a way that it MUST be overflown?Thanks, Thomas.

[Tabs 2,790]

Not in the FMC itself (per the real thing). What you can do however is edit the SIDSTAR text file for the airport if that's where the waypoint is occuring - just add "OVERFLY" after the "FIX" or "NAVAID" command that defines the waypoint.Ex. FIX OVERFLY SILOW AT OR ABOVE 21000 would tell the FMC to overfly the SILOW intersection at or above FL210, which is part of a KPHX SID...For manually entered waypoints, the plane will always use LNAV turn prediction and begin the turn slightly ahead of the waypoint.

[Guest Just747-400]

I guess that was discussed before, but fly by or fly over wpts are part of the data base. There is no way that a pilot can program manually such a wpt. So, if that wpt is not defined as a fly over, the LNAV will not fly over.Sorry.

[tstiegler 0]

Thanks guys, understood.Do you know how real world pilots handle such a situation? Do they use HGD SEL instead of LNAV or will they insert a fix before the waypoint to ensure that it will be overflown?Thanks, Thomas.

[Guest Voodoo]

Thomas,if you want to use LNAV; you could open the FIX page and create a pseudo waypoint which is on the same heading you are approaching the waypoint and for example one mile away from it. That should result in overflying the waypoint and making the corresponding turn to the next one. I take it you know how to create a FIX and add it to your route? :)reagrds,Christianhttp://img.photobucket.com/albums/v232/chrismo/sigsky.jpgVacation: wasted time between 2 flights!

[emvaos 13]

Thomas,Create an along route waypoint at 0.1 miles behind (above) the waypoint you want to overfly. Result guaranteed !I like the term shortcut...I call it turn-anticipation !Best,Vangelis===================================== E. M. Vaos Precision Manuals Development Group www.precisionmanuals.com=====================================

[tstiegler 0]

Thanks, Thomas.