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gbalean

737 Descent Dillemmas

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G'day allI've been struggling with the descent-approach-landing part of the flight. My problem is, although I insert the wind speeds and the like to predict the descent path, it still requires the speed brakes to be deployed to get it down to 240kts below transition altitude. Once this is done everything goes fine until just prior to turning on final, where I have to disengage the FMS to slow it down from 240kts. I shouldn't be coming in at this speed surely?? Would I be doing the right thing disengaging the FMS at this stage? Should I be slowing down earlier?Basically, I need to know what should be done during descent, approach and landing in terms of the FMS, airspeed and disengaging systems (not the checklist).If you could help me on this matter it would be greatly appreciated. :D Thanks a heap,Geoffrey Balean

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Geoffrey,This might be of minor consolation, but the simulation has a minor discrepancy: During a VNAV path descent, the power is not reduced to idle. If everything goes as it should, the airplane will maintain power at cruise until the FMC determines it can make a power-off descent

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I've had the throttle decrease approaching a TOD but can't seem to get it to descend? I've tried reading the manual but still nothing works. What could I be doing wrong?Kind Regards,

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>I've had the throttle decrease approaching a TOD but can't>seem to get it to descend? I've tried reading the manual but>still nothing works. What could I be doing wrong?>>Kind Regards,>Do you get "RESET MCP ALTITUDE" warning on your FMC...??? If so reset the altitude to your new alt and the a/c will descend at the TOD...all the best and happy landingsTim 10 miles east of LPFR :-beerchug

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I thought the autopilot followed the descent altitudes from the FMC not the MCU, when flying with VNAV & LNAV operating?Brad.

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>I thought the autopilot followed the descent altitudes from>the FMC not the MCU, when flying with VNAV & LNAV operating?>Brad,Negative. The plane follows what is set in the MCP ALT box. ATC might get mad at you if you descent before they want you to :) However, once you reset the MCP ALT prior to T/D in VNAV mode, the plane will cross the T/D pseudo waypoint and then descent via the FMC descent restrictions, until it hits the MCP ALT level where it will enter ALT HOLD.

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>Do you get "RESET MCP ALTITUDE" warning on your FMC...??? If so>reset the altitude to your new alt and the a/c will descend at the>TOD...>all the best and happy landingsNo, I set the MCP alt down to 3000 in the instance which I use (YSCB Canberra to YSSY Sydney) which is the altitude it should be at at when turning on final.I've been looking at other websites, and I tried a speed descent. This worked fine. However I'd still like to get the path descent working.Do you turn off the FMC so you can get to flaps 5 manouvering speed before turning on final?Thanks to all for your comments and a happy 2004!Geoffrey Balean

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You don't have to turn the FMC off, you could insert a speed in the legs page at a waypoint near where you want to slow down.Even simpler it to extend the flaps. If you have the DES page on screen, you can see how the speed restriction gets lower with each higher flap setting you choose, so the aircraft will slow down on its own. This method, however, would probably be frowned upon in RW operations :-)Leo BakkerBTW, I recently did some path descents and they were spot on! However, you have to make sure that if there is any wind you put that same wind in the DES FORECAST page, or else the FMC has no fair chance!

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