“Descent requires before waypoint” on foreflight?

Discussion in 'Technical Corner' started by TheGolfPilot, Oct 1, 2019.

  1. TheGolfPilot

    TheGolfPilot Line Up and Wait

    Joined:
    Jan 16, 2015
    Messages:
    762
    Location:
    Modesto, CA
    Display Name:

    Display name:
    Golfpilot
    It doesn’t make any sense they have descent required to destination but don’t have descent required to next waypoint. There is even a place to put you altitude at the waypoint. I wonder why they don’t add this functionality.

    Do any other programs do this?


    Sent from my iPhone using Tapatalk Pro
     
  2. EdFred

    EdFred Touchdown! Greaser! PoA Supporter

    Joined:
    Feb 25, 2005
    Messages:
    24,101
    Location:
    Michigan
    Display Name:

    Display name:
    Ed Frederick
    Garmin GNS (and I'm sure the rest of the garmin GPS) has that functionality.
     
    midlifeflyer likes this.
  3. Salty

    Salty En-Route PoA Supporter

    Joined:
    Dec 21, 2016
    Messages:
    4,802
    Location:
    FL
    Display Name:

    Display name:
    Salty
    Garmin pilot does not.
     
  4. midlifeflyer

    midlifeflyer Touchdown! Greaser!

    Joined:
    May 25, 2006
    Messages:
    10,256
    Location:
    Chapel Hill NC
    Display Name:

    Display name:
    Mark
    They will. The later units will let you input the altitude targets directly into the flight plan.

    There are also apps such as Sporty's EFB (and a plain simple calculator) which will do the basic calculations.
     
  5. Doug Reid

    Doug Reid Pre-Flight

    Joined:
    Dec 29, 2013
    Messages:
    49
    Location:
    North Carolina
    Display Name:

    Display name:
    Doug Reid
    You need to figure this in your head. For a normal 3 degree descent, allow 3 miles per thousand feet you need to lose...multiply your groundspeed times 5 to get the descent rate. Example.....you need to lose 3 thousand feet....that would be started 9 miles out. Next if you are going 150 knots, five times 150 is 750...750 feet per minute. If that rate is too much and you want to cut it in half, start your descent 18 miles out at 375 feet per minute. Problem solved...learn to figure in your head...do not always rely on a gadget.:)
     
    1RTK1 and dtuuri like this.
  6. Unit74

    Unit74 Final Approach

    Joined:
    Mar 8, 2014
    Messages:
    6,632
    Display Name:

    Display name:
    Unit74
    Too much math for me... I just use the ticker on the ForeFlight tray
     
  7. midlifeflyer

    midlifeflyer Touchdown! Greaser!

    Joined:
    May 25, 2006
    Messages:
    10,256
    Location:
    Chapel Hill NC
    Display Name:

    Display name:
    Mark
    Me too. Well, for in my head, anyway.

    Actually, I don't expect Foreflight to do everything. Sometimes, when I look at all the things it does and that I have no desire to use, I think it does way too much already.
     
    MuseChaser likes this.
  8. Bill Jennings

    Bill Jennings Touchdown! Greaser! PoA Supporter

    Joined:
    Mar 2, 2005
    Messages:
    10,755
    Location:
    Southeast Tennessee
    Display Name:

    Display name:
    This page intentionally left blank
    My head calculation is a bit simpler. Take target pattern altitude minus present altitude, that gives you altitude to lose. Say it's 7000ft. 7000ft divided by 500fpm gives 14min of decent. Really I just take altitude to be lost in thousands and double it, and that's your minutes. Mooney in full power decent at 500ft/min does about 180kts, or 3mi/min. So, 14min * 3mi/min says I need to start decent 42 miles from the airport. I usually add 10mi to the number (52mi in this case) and request decent at that time. Center or approach doesn't always give you the decent immediately.
     
    Last edited: Oct 2, 2019
    jwyatt likes this.
  9. Doug Reid

    Doug Reid Pre-Flight

    Joined:
    Dec 29, 2013
    Messages:
    49
    Location:
    North Carolina
    Display Name:

    Display name:
    Doug Reid
    Really? This is too much math ? WOW !

    I hope your ipad doesn’t die. I use descent to destination during a non precision approach as a cross check on final...it is a nice feature. But I figure standard descent from cruise to pattern in my head...it is good to keep your brain active.

    Just remember 3 and 5...3 miles per 1000 feet and 5 times groundspeed.
     
  10. EdFred

    EdFred Touchdown! Greaser! PoA Supporter

    Joined:
    Feb 25, 2005
    Messages:
    24,101
    Location:
    Michigan
    Display Name:

    Display name:
    Ed Frederick
    I dont worry about distance to waypoint. Only time. Makes all the calculations simpler especially if you plan at 500fpm. We should all be able to multiply by 5 in our heads - or 2. Like Bill said. How many 1000s of feet do we need to lose? Double that and that's how many minutes out you need to descend. No need to overcomplicate it with GS.
     
  11. Doug Reid

    Doug Reid Pre-Flight

    Joined:
    Dec 29, 2013
    Messages:
    49
    Location:
    North Carolina
    Display Name:

    Display name:
    Doug Reid
    Your method is fine if you know how to use it. The point is to get your brain involved !:)
     
  12. Bill Jennings

    Bill Jennings Touchdown! Greaser! PoA Supporter

    Joined:
    Mar 2, 2005
    Messages:
    10,755
    Location:
    Southeast Tennessee
    Display Name:

    Display name:
    This page intentionally left blank
    And really for my case and decent rate/speed, I just need to take altitude to be lost times 6, and I get my decent point. I just wanted to show that the math isn't hard, especially at a 500fpm decent rate.
     
    flyingcheesehead and Doug Reid like this.
  13. midlifeflyer

    midlifeflyer Touchdown! Greaser!

    Joined:
    May 25, 2006
    Messages:
    10,256
    Location:
    Chapel Hill NC
    Display Name:

    Display name:
    Mark
    My brain is always involved when I fly. Just not in doing mental math if I can avoid it.
     
  14. TheGolfPilot

    TheGolfPilot Line Up and Wait

    Joined:
    Jan 16, 2015
    Messages:
    762
    Location:
    Modesto, CA
    Display Name:

    Display name:
    Golfpilot
    Ya. I can do the math, but when there is a handful of them going into an airport that in LA with a jet that only has a 430 in it, it would be really nice to have the $200 a year flight calculator I carry around do that basic math for me. And it could keep doing the math for changing air speeds during the descent, it would be nice to have.

    They already do this calculation to the destination, why can’t they implement it to the user defined altitude point at a waypoint?
    If Garmin Pilot does this I may have to take a look a switching cause I would


    Sent from my iPhone using Tapatalk Pro
     
  15. EdFred

    EdFred Touchdown! Greaser! PoA Supporter

    Joined:
    Feb 25, 2005
    Messages:
    24,101
    Location:
    Michigan
    Display Name:

    Display name:
    Ed Frederick
    Anyone ever see the movie Wall-E ?

    1000fpm - Multiply by 1.
    500fpm - Multiply by 2.

    Life is hard.
     
  16. Unit74

    Unit74 Final Approach

    Joined:
    Mar 8, 2014
    Messages:
    6,632
    Display Name:

    Display name:
    Unit74

    Been flying with iPads for at least 5 years now. Can’t say that’s been a problem. And honestly, it’s really unimportant to begin with. If I’m VFR, my eyeballs will judge the decent. If I’m IFR, ATC till established and then the rest of the technology tells me what to do.

    But thanks for trying to tell us how smart you think you are.
     
  17. Doug Reid

    Doug Reid Pre-Flight

    Joined:
    Dec 29, 2013
    Messages:
    49
    Location:
    North Carolina
    Display Name:

    Display name:
    Doug Reid
    You are welcome ! :)

    Bill Jennings and I will be performing here all week and drinks are half price on Thursday nite !
     
  18. Archer Jack

    Archer Jack Pre-Flight

    Joined:
    Oct 24, 2018
    Messages:
    62
    Location:
    Mansfield, TX
    Display Name:

    Display name:
    Jack
    Hope you have a decent descent:)
     
  19. PaulS

    PaulS Final Approach

    Joined:
    May 29, 2007
    Messages:
    8,811
    Display Name:

    Display name:
    PaulS
    There's usually a little dot on the magenta line. Start decent there.
     
  20. JOhnH

    JOhnH Touchdown! Greaser! PoA Supporter

    Joined:
    May 20, 2009
    Messages:
    11,773
    Location:
    Florida
    Display Name:

    Display name:
    Spun Out
    That is the real answer.
    Of course, it requires knowing how many minutes out your are, but I have at least 5 sources in my cockpit for that information.

    If I'm at 7,000 ft and I need to descend to 1,000 feet, (6,000 ft descent), that will take me 12 minutes at 500 ft/min. I start descending slightly before 12 minutes out.
    The only time I worry about descending to a waypoint is for the approach fixes in an IFR approach. Then I just descend to the assigned altitude and maintain.
     
  21. Bill Jennings

    Bill Jennings Touchdown! Greaser! PoA Supporter

    Joined:
    Mar 2, 2005
    Messages:
    10,755
    Location:
    Southeast Tennessee
    Display Name:

    Display name:
    This page intentionally left blank
    Dammit Jim, I'm a pilot not a spellchecker...
     
    DaleB likes this.