Greetings all,Is there a way to program the MCDU to cross a fix at a specific time? During the Cross The Pond event, I was told to cross a waypoint "not before 1410Z". Besides the obvious answer (slowing down and watching the PROG page to see when the expected time for that fix changes), is there a way to specifically enter a crossing time for that fix? Many thanks.

Nope. Quick mental math is all you need. If you'd rather not do the math, enter a SEC FP and give it a different cruise speed and it'll tell you when you'll cross.

Yes. You can do this by changing the Required Time of Arrival. There are instructions of how to do this in the FMS Manual, page 'FMS.30.9'. After specifying your RTA, the plane will increase or decrease its speed in a way that will allow it to cross the navaid at the time you programed.

Learn something new every day. Nice!

Learn something new every day. Nice!

Oh yeah. I didn't know about this too until two or three days ago (no kidding!). That day I was in a loooong flight with the MD-11 and decided to read the manuals. I started by the FMS manual and discovered that. People generally ignore the manuals and try to learn things by their own, especially when they are too long, but you'll learn a lot from them. That's one of the many reasons of why people should read the manuals. :(

Thanks, Matheus.......I just read that item in the manual. It says it is used for waypoints 1 hour or more downtrack, but I only had perhaps 30-40 minutes to go. Would have been nice to have seen if it worked.

Try this anyway. When I discovere this I was about to reach my destination, but I tried with a waypoint during descent and worked. I think that this one hour thing is just to increase precision and fuel economy.

I happen to be working at NASA Ames and we do a lot of research for FAA about this sort of things. Ability to not only arrive at a certain point (lat,long,alt) but also to arrive at this point at a specific time is called 4D (as opposed to 3D). 4D would call for aircraft to have its software so finely tuned that you could meet the time with great accuracy (say +/- 10 sec). According to FAA standards no aircraft currently flying with airlines is equipped with 4D capability. No US traffic controller would demand of a pilot to arrive at certain point at a specific time - unless it is a pretty crude thing (like for transoceanic operations). FAA puts a lot emphasis on 4D for future operations, there may even be certain classes of airspace specially created where you would have to be 4D equipped to fly in that airspace. This is all part of the ongoing current research.

I happen to be working at NASA Ames and we do a lot of research for FAA about this sort of things. Ability to not only arrive at a certain point (lat,long,alt) but also to arrive at this point at a specific time is called 4D (as opposed to 3D). 4D would call for aircraft to have its software so finely tuned that you could meet the time with great accuracy (say +/- 10 sec). According to FAA standards no aircraft currently flying with airlines is equipped with 4D capability. No US traffic controller would demand of a pilot to arrive at certain point at a specific time - unless it is a pretty crude thing (like for transoceanic operations). FAA puts a lot emphasis on 4D for future operations, there may even be certain classes of airspace specially created where you would have to be 4D equipped to fly in that airspace. This is all part of the ongoing current research.

Very interesting, thank you Cheers,