FMC problems

[Guest langevine]

Please ignore speeds. etc. Just look at the FMC and HSI.This is arrival at KIAD from Jasen arrival to RW 1R.picture 1 on arrivalpicture 2 downwind -- note the little prompt at lower r on FMC to choose intercept trackpicture 3 downwind with approach path active.picture 4 on final.

[psolk 3,040]

hmmm... did you mean to show the PMDG 737?-PLiquid CooledAMD 4000 San Diego2 Gigs Kingston Corsair XMS CL2Dual 7800 GTX 24 inch widescreen dual 19 inch LCDRaid-0

[Guest langevine]

yes, because it isn't implemented in t he PSS. I wanted to show how it is supposed to work. ---leo---

[psolk 3,040]

LOL, Can you show the PSS Bird now with her line from nowhere...Thanks Leo,-PaulLiquid CooledAMD 4000 San Diego2 Gigs Kingston Corsair XMS CL2Dual 7800 GTX 24 inch widescreen dual 19 inch LCDRaid-0

[FOD 23]

LeoI have recently been looking in detail at the way the PSS 777 handles waypoints and found your notes above very interesting. I was searching for anything which might cause the early turns and disappearing waypoints during approaches. Of note, when an early turn occurs, that waypoint disappears and the FMC does not try to recover the original planned track between waypoints - instead the FMC points the aircraft directly at the next waypoint and sets this up as a new track to this waypoint.This is the reverse of, for example, the Airbus programming - here the waypoints remain during the turn and the aircraft initially sets heading to recover to the original planned track between waypoints. Only then does it turn towards the next waypoint.From your post it appears that the rw 777 FMC operates as per the PSS version BUT allows the pilot to select an intercept heading so that the aircraft can recover the original planned track between the waypoints - which of course is the track that ATC expects you to fly and on which VNAV bases its descent planning. Also note on your 737 examples that the magenta track on the ND remains showing behind the aircraft - as you know on the PSS 777 the magenta track always stops at the aircraft symbol.I do not have PMDG - happy with PSS so far - and I have never used FMC in my rw flying - the F4 is much more agricultural! So very grateful if you could comment on my understanding of how the rw 777 handles waypoint turns.Many ThanksJohn R

[Guest langevine]

The aircraft isn't like PAC MAN. It doesn't gobble up waypoints. After crossing a waypoint, it is eliminated from the route.The FMC computes a turn over a waypoint and generates a track that will keep you within the confines of an airway. At any point along the track, you can line select to go direct to any waypoint and have the option to go PP Direct, HS to intercept a selected track or even track FROM a waypoint. If you are on an ATC vector, they cleared to intercept your route, you are able to select a heading to intercept the existing track, create a track direct to a waypoint or even create a point along the track to fly direct to and then continue on course.PSS does a pretty good job of modeling the FMC, just didn't include all its features as they exist on the 777.I recently flew a PSS 777 flight from KORD to KIAD. I used VNAV from 400' on departue and used HS until given on course by ATC. It all worked as expected. I even updated and changed some waypoints and the speed and altitude at some waypoints and it ALL WORKED. On some previous flights, it didn't work, so I must have some buggies in my system.I had no ATC on arrival at KIAD, so did my own headings and altitudes for the transition to ILS approach and all was well until just inside the OM with all systems normal and the goofy thing decided to go FULL POWER. I quickly turned off the AT, got back on GS and continued for an autoland. Never did figure out what caused that power surge. The AP never disconnected (it would have in RW) and I managed to keep it on the runway after landing. :-)Happy flying. Keep it safe and interesting.---leo---

[FOD 23]

LeoVery many thanks