Hi guys, today I tried the circle to land approach at Nice, and after having a go at flying it on raw data I programmed the route into the fmc using a mixture of pilot defined waypoints and known intersections ( e.g SINRA and DRAMO). I put in the altitude restrictions and set appropriate speeds for each, for instance at SINRA it was 240/6000, and at RIVRU it was 220/2500. I approached the first waypoint at 6000 in lnav and vnav. The plane was at 250knts and didn't slow down at all approaching SINRA. There was also no decel point put in, but there was one before RIVRU. The plane started to decend after SINRA, but at the vnav descent spd of 290, even thought he restrictions were clearly there on the descent page. Should I have been in VNAV spd for this phase of the flight? And why did the plane not slow before SINRA? the legs page looked as followsSINRA 240/6000DRAMO 240/6000LUC001 220/3500 where luc001 is d38.0 luc rad 086RIVRU 220/2500the rest is a visual approach using the coastline as a guide.Any help or ideas appreciated,ant

HiAlthought not exactly like yours,i have similiar problems with decent, i have to use my spoliers as soon as i reach T/D to counteract the increase in speed, which if you do not do anything results in VNAV getting disengaged and stuffing up all the other descent parameters, i don't understand why this problem was left out in the initial release.

I am flying it again, this time I have set tgt speed in crz page to 250, so the decel should be easily achievable in vnav, will let you know the result. I think the problem may be that it is such a short descent path, maybe I am better off using v/s,cheersant

Hi, tried it again, this time cruising at 250 knots. The speed restrictions on the legs page were still ignored, why is this?(I have tried to upload the pics, but they are too large, anyone know how to compress them down a bit?)So does the crz tgt speed on the crz page override legs restrictions? I thought that if you are in lnav and vnav the fmc will try and abide by all such speed restrictions, or am I missing something obvious?cheersant

I have been experiencing a similar problem during the climb to cruise altitude. If the aircraft is climbing below 10000' with the 250/10000 speed restriction on the CLB page at 250 kts you then delete the speed restriction in the usual way (press DEL key then the appropriate line select key) the target speed changes to 290 kts in the fmc out the indicated speed remains at 250kts. The only way to change it is to deselect vnav then reselect it, at which point the speed bug on the speed tape jumps to 290kts and everything works correctly.Any ideas.

I have been reading Bill Bulfers fmc guide and found out the following. You cannot specify speed restrictions on the legs page if the leg is part of the cruise portion of the flight. The fmc will ignore these restrictions and stick to the speed specified in the crz page. I came unstuck because I took off and flew at such a low altitude, if I had gone to fl10 for instance, and then put the legs of the approach in as part of the descent, all would have been well. This differs from the honeywell fmc, where you can specify a speed restriction on the legs page even for the cruise. Hope that makes sense,ant

"This differs from the honeywell fmc, where you can specify a speed restriction on the legs page even for the cruise."I'm not so sure about that, Ant...According to the Big Boeing (Honeywell) FMC Users Guide (and several other manuals), "Speed entries are not permitted for cruise wpts on the LEGS page except for a HOLD AT wpt."I know PS1, for example, was modified after it had been released to inhibit entries in cruise ;-)Cheers.Ian.

Hi Ian,I thought you could specify a certain portion of the cruise to be at a different speed then the rest of the cruise (honeywell fmc again). I've never tried it in ps1 myself ( doesn't seem much point really!), but I'm probably wrong - this is the problem with trying to keep on top of two different types of fmc, not to mention the airbus mcdu! I'm slowly working my way through the 737ng fmc guide, and there are a LOT of differences to the big boeing fmc. For instance I don't recall the rta function being available - I used to adjust the cost index to get my eta right, I hope rta is in su2, as it looks likea nice feature.cheersant

Ian, have just found that you are right, I quote from the big boeing fmc guide,"Speed entries are not permitted for cruise waypoints on the legs page except for a HOLD AT wpt."However, on page 100 it goes on about "Constant Speed Cruise Segmentswhich is where I have gotten mixed up. This is a little confusing, it seems to be only available on the 777? Have a look and see what you think, but at the end of the day we're talking about the 737ng, and in real life how often do you take off and fly at 6000ft before executing a circle to land?cheersant