Leg sequencing on a modified route

[Dirk Schepmann]

Good afternoon,

I made a small mistake during preflight today and noticed an interesting behaviour of PSX.

I was taxiing out for departure when I realized that I forgot to request the winds for accurate FMC predictions. So I made a wind request, but forgot to activate the modified route. I lined up and performed the takeoff. At that time I didn't notice that the route had become dashed. The aircraft correctly followed all waypoints of the SID and honored all speed restrictions, although the route was not activated (I think it's normal because it had been activated once before performing the wind request).

In the climbout I eventually noticed that the modified route with the winds hadn't been executed and corrected my mistake. Immediately after doing that, the first waypoint of the SID become the active waypoint and the aircraft turned back to the airport.

It makes sense to me (no leg sequencing while the modified route is waiting for a confirmation) but I'm wondering if the same would happen on the real thing.

Best regards,
Dirk