737NG VNAV PATH QUESTION (new S/N)
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Thank you 737jock. Your hours are nearly the same as mine, so I would have thought by now that you'd have learnt that what the manual says is not always what the aeroplane does. VNAV disconnects from overspeeds into the clackers are not unusual with cost indices over 50. If you have 10k on type, you must surely be familiar with that? And you must also be familiar with how VNAV will get you to the start of the approach about 30kts too fast if you programme the FMC with all the available data and have a planned continuous descent from the cruise. What the manual says is dandy, but if you are a trainer, you should be teaching what actually happens - we fly aeroplanes, not manuals.
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Does the 747-400 VNAV work the same as the 737?
We (my airline-744 airframe) don't have an FMC Supplementary Data Document, and oftentimes the VNAV does some odd things. I would like to know more about how/why it works/doesn't work.
We (my airline-744 airframe) don't have an FMC Supplementary Data Document, and oftentimes the VNAV does some odd things. I would like to know more about how/why it works/doesn't work.
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Interesting how different the experiences are with VNAV. Granted, we do fly low cost indices these days (below 10), however VNAV tends to be slower than calculated if the descend forecast page is filled in with up to date info. The beauty of low CI flying is though that one doesn't need to care much about unexpected short cuts. The bad side is that it is extremely slow which isn't much fun and can cause ATC sequence problems.
Glad I don't fly the Maggot...
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VNAV disconnects from overspeeds into the clackers are not unusual with cost indices over 50.
Usually to do with the fact that the aircraft only allows for a small margin in Mach technique and when KIAS is increasing speed (as VNAV is trying to retaining a fixed Mach until a precomputed KIAS is achieved) VNAV does not always allow much room for error. This can be mitigated by slowing the Mach in descent a bit to artificially enhance a slightly greater margin, but of course you know that already.
If you have 10k on type, you must surely be familiar with that?
Your hours are nearly the same as mine, so I would have thought by now that you'd have learnt that what the manual says is not always what the aeroplane does.
VNAV will get you to the start of the approach about 30kts too fast if you programme the FMC with all the available data and have a planned continuous descent from the cruise.
VNAV behaves by the book, BUT VNAV is only able to calculate as good as the data that goes into the FMC, so when we ensure the inputs are good we thus avoid outputs to be bad.
What the manual says is dandy, but if you are a trainer, you should be teaching what actually happens - we fly aeroplanes, not manuals.
atpcliff: Does the 747-400 VNAV work the same as the 737?
And please, no, I do nor did try offend any person in this thread.
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I'm quite happy to know that there are many fellas who don't trust VNAV 100%. I thought I was part of a minority... Even though some say I come from the "Children of Magenta" generation, I can't avoid doing my maths (altitude to lose + deceleration) and keeping myself "flying ahead of the plane" during descent ! 
Changing the subject a little, I would like to ask you guys one more thing:
Does anyone here fly acfts equipped with the Honeywell RDR-4000 ? Any thoughts about that one ? Even after reading the Pilot's Guide over and over, this WX Radar seems quite choppy in my opinion (yeap, I do switch from Auto to Manual to sweep the weather ahead and have a better view of what's waiting for me).
I don't know if It is the new 737NG's "standard" WX Radar or if It is my company's choice, but I really prefer previous radars over that one. I think they were much more "trustable"...
Happy 2014, by the way ! I hope you had a day off on the new year's eve...
Changing the subject a little, I would like to ask you guys one more thing:
Does anyone here fly acfts equipped with the Honeywell RDR-4000 ? Any thoughts about that one ? Even after reading the Pilot's Guide over and over, this WX Radar seems quite choppy in my opinion (yeap, I do switch from Auto to Manual to sweep the weather ahead and have a better view of what's waiting for me).
I don't know if It is the new 737NG's "standard" WX Radar or if It is my company's choice, but I really prefer previous radars over that one. I think they were much more "trustable"...
Happy 2014, by the way ! I hope you had a day off on the new year's eve...
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Rbecca: The RDR 4000 radar is a magnificent piece of equipment. But like any information what is given to you in the flight deck, it requires understanding first. I do not blame you going back to a simpler mode, if that assures you better, but recommend a good read of it's manual.
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@rsbessa it might be the standard radar for your fleet, however it is a customer option and there are other options available of course. For example we use the competing rockwell collins WXR-2100 which actually works very well in automatic mode.
