TOD

[Guest skyhog]

Hi JD, just wondering how the TOD is calculated. Is there a formulathat is used depending on cruise FL? Using the FMC in the PMDG 737 Igot my first decent 60nm from the TOD in the FMC. I was enroute to KMDW. FISDO now where in sight. Cheers

[Guest bobsk8]

I don't know how they predict the TOD in RC4 but it probably has something to do with the 3 - 1 rule, multiply altitude in thousands times three and and start descent x miles before that. I find that the TOD in RC4 generally happens around 20-25 miles prior to my Level D 767 FMC suggests. Better a bit to soon than too late in my opinion.

[jd 57]

i know i answered this once before very eloquently. do a search on TOD or 11000 or 12000. if you still can't find it, i'll write it up againjd

[Bera 0]

Hi all,What would be cool is to have option 'descent when ready' from cruise altitude when above FL240. Then FMC capabilities on advanced addons like LDS or PMDG could be utilised even better.Also I suppose this is also a realistic procedure if allowed by circumstances - atleast I can recall in real world getting this sort of clearance on flights into EFHK and ESSA when I have been able to get the jump seat on flightdeck for my flight.Also with previous RC version one was able to ask (and obtain) cruise level again after initial descent and when at FMC calculated TD ask for lower levels to FL 150 and the get final clearances from there. I do miss this a bit since initial descent (380 - 350 etc.) during low traffic levels/areas comes very early for most addons. Best Rgs Perttu

[John Burgess 0]

Hi Perttu,It's already there :-)When told to descend from cruise choose the '3 PD' option.You will request the descent at pilots discretion. Usually it will be allowed.All the best,John

[Guest mmcevilley]

>Hi Perttu,>>It's already there :-)>>When told to descend from cruise choose the '3 PD' option.>>You will request the descent at pilots discretion. Usually it>will be allowed.>>All the best,>>John... note that the PD option only displays if YOU have comms. -michael

[Ray Proudfoot 9,038]

Let me add my bit to this discussion since I used it frequently during testing. How successful you are in getting a PD depends on time of day (night will be more successful than day) and the number of runways at the destination airport. Lesser is definitely better.But, there's a little workaround to this if you're refused the first time. After a refusal the option remains so just keep requesting (nagging) and eventually the controller will lose the will to live and grant you a PD. I believe this also works for male pilots as well as female ones :-lolCheers,

[Bera 0]

Hi John,Thanks, I guess I should read the manual...Everything has been working so well that I have not bothered reading it thru sofar. Best Rgs Perttu

[Guest skyhog]

To add to my first question. What does ATC expect for a decent rate?The initial decent rate from FL380 say, is the timing based on FPMand what would the norm be.

[jd 57]

if the distance to the arrival airport is less than (plane altitude - arrival elevation) / 250 then i start you downjd

[Guest mmcevilley]

>To add to my first question. What does ATC expect for a>decent rate?>The initial decent rate from FL380 say, is the timing based on>FPM>and what would the norm be. Very good question - and no definitive answer. The bottom line is this - if you are not descending at a high enough rate, ATC will let you know! ;-)FWIW: If I get an early descent (early defined as 40+ miles before my calculated T/D), and I accept it (that is, do not request and get a PD), I might start down at a rate as low as 500 FPM. But usually, I'll go with 1000 FPM.In other instances, I will engage the DES NOW mode, which for my aircraft initiates a descent at 1200 FPM until intercepting the pre-calculated descent path. Sometimes that intercept does not occur until below FL270.-michael

[Guest skyhog]

Thanks JD & Michael, that is what I was looking for.