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asz

T/D in FMC

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Hi everybody and Happy New Year,My yesterday flight ended in a disaster!I flown from KDEN to KLGA and elected to fly at FL410 (as recommanded by FMC), looking in the planed flight I realized that the T/D is too close to the arrival to allow a safe landing (MILTON FOUR ARRIVAL), but thinking that the FMC know his business I let him fly the route! Few miles after the T/D the same FMC started to yell at me that the descent path in inachievable,-diconected the AP, tried to bring down the bird manually, overstressed the frame and . . . ups! finished, having few lines in the local breaking news.I am able to calculate the T/D all by my self, but I have a very expensive computer ( with a plane attached to it) to do this calculation, so my question is where do I faulted or what is the right procedure?Thanks in advance for any light!AndrePS: before the SP1b, when started with D&C panel, the FMC allowed to load the pax and fuel, now you need to connect the batterie to do the same, it is more realistic but it is so ?!

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before the SP1b, when started with D&C panel, the FMC allowed to load the pax and fuel, now you need to connect the batterie to do the same, it is more realistic but it is so ?!
No,in cold and dark state pressing the menu button on the CDU a few seconds will do the trick.

Martin Bunjes
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Finding a good T/D is not hard math to get a roundabout figure,3-6 rule works fine.Example30,000 feet to loose = (3*30)=90 miles250 knots (assuming ground speed) (250*6)=1500 feet per minute (FPM)In-case your using a different calculation.(I have to use this when flying the Flight1 Cessna Mustang as it has no VNAV)Also did you use the Forecast page within the DES page to allow for winds as the direction you were flying should have given you a tailwind? This page let's the on board computers have the ability to look ahead and not just take conditions as they come.And having a high CI can lead to some steep descents I'm sure if using CI into the 100's


-Raven Harris
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PMDG - 747-400/8iF | MD11/F | BAe J41 | 737NG 6/7/8/9 Hope ER/BBJ|777LR/F
Flight1- Cessna Mustang

 

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Few miles after the T/D the same FMC started to yell at me that the descent path in inachievable
Were you in a descent, or were you level? What was your speed? What was your CI? What did your FMA say? Were you at idle (below 40%N1 at your TOD).
,-diconected the AP, tried to bring down the bird manually, overstressed the frame
Why disconnect the autopilot? If you can't get the A/P to do what you want it to do, then you should disconnect the A/P, but was that the problem? The path and the A/P are not the same.Level Change or VNAV in Speed Int would work just fine.Lastly: Don't overstress and airframe to meet a restriction.

Matt Cee

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Thanks for all the advises, will come back after the next flight.In fact I forgot to look in to the forcast pages.A.

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Many of the SID/STARs don't actually have the crossing restrictions hard set. You need to add them in. If you look at the chart and it says "Expect to cross at 10,000 and 250 knots" chances are, you'll have to enter that yourself. Some arrivals have hard altitudes as part of the procedure, and those are set in (SHNON2 into IAD, as an example).What was your C/I? If it's too high, the descent will be later, because it assumes you'll be descending at a higher speed, which requires a steeper descent angle.


Kyle Rodgers

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Hi, just for the reccord, savely arrived at KLGA.I "performed" a lot of newbie's errors (strong tailwind, put the wrong restrictions, ect, ect.)Thanks again.A.

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