# Time for descent

## Recommended Posts

For figuring out what time to begin your descent I have been using the windows calculator. GSx101.3=FPM/5280=miles per minute take that and the time it will take to decend from altitude to desired altitude=range in miles from the airport to begin the descent (make sense to anyone?) Is there another way to figure this out, or am I doing it right.

##### Share on other sites

scoochy:Wow, all of that sounds way to complicated. I read in FLYING magazine once that a good convention was to take the first two digits of your flight level and multiply by 3. So for FL 300 (30,000 ft) it would be 30 x 3 = 90 miles out. I usually pad this a little by using 4 as a multiplier in the heavy jets I usually fly. So in the example above I would begin my descent at 30 x 4 = 120 miles out. This seems to get me down in plenty of time, assuming a standard descent rate of 1800 ft/min at about 290 knots indicated airspeed above 10,000 ft, after which time I slow to 250 or below. Hope That helpedAlex ChristoffN562ZMinneapolis, MNThermobulb@aol.com

PowerSpec G426 PC running Windows 10 Pro 64-bit OS, Intel Core i7-6700K processor @4.0GHz, NVIDIA GeForce GTX 1080 8GB GDDR5 VR Ready, ASRock Fatal1ty Z170 Gaming K6 motherboard, 2TB HD + 500GB SSD, Acer Predator X34 34" curved monitor (external view), Samsung U28E590D 28" Widescreen LED Backlit UHD monitor (panel view), P3Dv4.5 64 bit

##### Share on other sites

I usually just wait until ATC tells me to descend..... With good descent management, it's usually pretty accurate for me.... :) Better than cancelling IFR to make your descent your way without ATC yelling at you... ;-)

Declared weather:  FSX: ASN / FS9: ASE

##### Share on other sites

In real life, commercial aircraft primarily...do most flights have ATC handling the descents or are pilots expected to report at the beginning of a STAR at the proper altitiude where they came out of the Flight Levels on their own.It seems to me ATC would not want that much latitude given to the pilots or at the very least an annoiuncement by the aircraft that it was beginning it's descent to it's assigned arrival altitude.I live in the New York area and when I fly we seem to be stepped down that I assume is being controlled by ATC.Overseas flight are probably different though...I gues they would initiate their own descents because I know on Eastbound flight deprating the Gander control area radio contact is lost.Thanks for anyone's thoughts on this.Greg

##### Share on other sites

Greg,In the US, all commercial traffic is required to fly IFR, so they are under ATC control at all times. ATC does not like it if aircraft descend or climb at their own will UNLESS the ATC specifically says "descend at your discretion..." usually followed by some guideline like "...cross XXXXX intersection at 11,000". THey might also include "report leaving FLXX". So it is up to you when you start the descent but you have to let them know when you do it.David

##### Share on other sites

Thanks David, that is pretty much what I thought.How often would an aircraft get a "descend at your own discretion" instruction.Is that kind of frequent?? I'm just curious.Thanks.

##### Share on other sites

I guess it would all depend on what part of the country you are in and how busy (or not busy) the airspace is.Out here on the upper Great Plains, it is very common to hear from Minneapolis Center "Descend at pilot's discretion", "Cleared as filed", or "Cleared direct".Keep in mind that I'm speaking of single engine/light twin IFR operations. It may be quite different for the people flying the heavier iron at the higher altitudes.Regards,ScottCFII/KJMS

"...now let's get this thing on the hump - we've got some flyin' to do!" ~ Major Kong from "Dr. Stranglove"

Scott Cebula

##### Share on other sites

Hi All:Next time you need to fly somewhere, fly on United. You can listen to the pilots talk to ATC, and boy does that make the flight time go by quickly!! You can take it a step further by using your FS flight planner of choice and devising a flight plan for the real-world flight and printing out a few of the most likely STARS they would use and follow along as ATC talk with the crew. Great fun! Then you can hear how they do it. Descents are basically controller directed, and I've heard a few "at pilot's discretion" clearances too, as mentioned above. And they pretty much adhere to the published crossing altitudes on STARS.Alex ChristoffN562ZMinneapolis, MNThermobulb@aol.com

PowerSpec G426 PC running Windows 10 Pro 64-bit OS, Intel Core i7-6700K processor @4.0GHz, NVIDIA GeForce GTX 1080 8GB GDDR5 VR Ready, ASRock Fatal1ty Z170 Gaming K6 motherboard, 2TB HD + 500GB SSD, Acer Predator X34 34" curved monitor (external view), Samsung U28E590D 28" Widescreen LED Backlit UHD monitor (panel view), P3Dv4.5 64 bit

##### Share on other sites

I think Scott really answered this but in areas with little traffic, it is very common. On the other hand, if you are flying along the eastern or western coasts, it is unlikely that you will be given so much latitude (or altitude, in this case ;-)). ATC understands that time and fuel equals money for airlines, now more than ever, and the airliners FMC does a pretty good job of maximizing profits. They would prefer to not interfere if possible. Just my take, thoughDavid

##### Share on other sites

Kind of what I thought.I'm in the NY area and have never heard an "at your discression" clearance.They keep 'em on a tight leash around here- EWR, JFK and LGA being worked heavily.In fact, ATC yells at the pilots when their response times lag..."Lear 145J quicker cadence on your response is needed, we are working the rush hour traffic here!"The pilots just double clicked their mic...was kinda funny.Thanks

##### Share on other sites

Sounds like you are listening to either Approach or the Towers. It's the Centers that you will hear them say "Cross XXX Intersection at 10,000, descend at pilot's discretion". Rick

##### Share on other sites

jerrycwo4There is a freeware program called, Easy Decent Calculator here at the Avsim library. heres some info on it.jerry"Where can I find future versions of the program?------------------------------------------------Try the list hvacc_pilots_team@yahoogroups.com, and www.AVSIM.com, www.FLIGHTSIM.gr sites.In AVSIM you can find it under the General Utilities section, searching by the program's name (Easy Descent Calculator) or by my name (Spiliotopoulos).Have in mind that there are other programs as well in the AVSIM library which are called "Descent calculator". This program will have my name as the author"

##### Share on other sites

Lots of Rules of Thumb here too:http://www.flightinfo.comLots of real-world aviation message boards too.Regards,ScottKJMS

"...now let's get this thing on the hump - we've got some flyin' to do!" ~ Major Kong from "Dr. Stranglove"

Scott Cebula

## Create an account

Register a new account

• Tom Allensworth,
Founder of AVSIM Online

• Flight Simulation's Premier Resource!

AVSIM is a free service to the flight simulation community. AVSIM is staffed completely by volunteers and all funds donated to AVSIM go directly back to supporting the community. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. Thank you for your support!