Calculating Top of Descent Point | Descent Planning Rules of Thumb

Calculating a Top of Descent (TOD) point is very helpful to ensure a smooth arrival. A few rules of thumb make this task much easier and can be done quickly in the cockpit. Here is a bit of background on where these rules of thumb come from.

[ryancross]

Currently studying for my CFII. Finding your videos is like stumbling upon a gold mine. 100% the best instructional videos on youtube.

[cari]

well, if you dont have any GPS in your plane, you may also need to calculate the ground speed with an E6B before doing these calculations

great video as always!

[arctain]

You can use ForeFlight to generate both a TOD waypoint and view a Descent to Destination (in feet per minute).

The nice thing about this is that - if you’ve accurately entered your Performance information for your Aircraft, and planned your route - with older avionics stacks, you can get much the same info on ForeFlight.

If, however, you just want to fly a general area and pick an airport to have lunch along the way (or get priority-diverted due to a family bathroom ‘emergency’), using Descent to Destination works extremely well. I’ve used it in both the 172 and the BL-17.

[AVIOCHAHINEMODELS]

Super clear ! Well explained. Good job 👏🏻

[mtnairpilot]

In the 530/430 there is a field you can put in the display called VSR (Vertical Speed Required) in connection with the VNAV function where you can input when you want to be at any altitude. It also works well when given clearances like "Cross 20 mi west of XXX at 8000". On that screen you have to put in your estimated/desired vertical speed, and it assumes the same groundspeed as in cruise, so you have to adjust for any speed increase in the descent. For example, I set it for 1200 fpm, knowing that I will actually descend at 1500 fpm. From that point it will give you time to TOD as well as an instantaneous readout of VSR, so you just need to match the numbers to hit your spot.

[Oldpuck]

For a PA28-180, descending at cruise spd of 120kts, divide your descent 11, 000' by 300, or, 110/3 = 36 nm. At cruise speed of 120kts, you'll need to descend ~600 fpm. My CFI said not to exceed 500-600 fpm for pax comfort, ears etc. What do you think of this method?

[_miguel_tenorio]

Hello, how do I calculate the fuel consumption for the descent?

[dam]

I live 12 miles away from our airport and aircraft that pass overhead are most usually I’m guessing 500’-1000’ up before landing. So they’ve made their descent long before.

[flyingwithsol]

does the MFD automatically display the alt intercept arc or do you have to select that setting?

[Mike-pfru]

I have a question.
There doesn’t appear to be any factoring of earth curvature.
I used all the numbers given and calculated that you would be 1200 feet higher than planned at the destination, since that would be the additional drop over 38 nautical miles.

[JonahCBR]

It seems I'm unable to enter altitude and offset in the g1000 nxi in MSFS2020. Does anybody know if this feature works similar to what the video shows at 04:59 ?

[keithmeline]

Do you have a video on the explanation of magnetic dips, variations, and turning errors? I understand course corrections but visualizing what a ‘magnetic compass will normally indicate a turn to the when a ____ turn is entered from a heading’ type questions are puzzling me..

[noagruber]

I love you you make everything so do able

[Dmiller_V]

Is this the default G1000 functionality in the sim? I assume your using MSFS.

[MojaveHigh]

Is the G1000 you are using the Working Title version? Some of the things you are doing (changing Direct To ALT/offset, adjusting VNAV profile) don't seem to work for me.

[JohnWatersKlas]

Loving your content! I have some calculations I made to explain the math for descents and CDI deflections, summarized in one image, that I would love to share - PM me if you want to see!

[Stefan-ghxr]

Thanks! You proved flat earth with this video :)
You cant triogeometry with a curved surface as baseline :)

[refness]

Man literally I was just looking for this calculation and you uploaded thank you😂❤️

[rfriesen]

One of my favorite youtube aviation channels. Thanks for all your content. It provided for great learning.

[petermerrick]

Try the The rule of 3 & 6. In a piston a/c if you have 10000 ft to descend use 6x10 = 60 miles to get down. use 3 x you GS as you decent rate. In jets: if you want to descend 10000 ft use 3 x 10 = 30 miles to get down use 6 x your ground speed for you decent rate. It’s simple you can do it in head. Slowing down use 1 mile per 10 kts in level flight idle power.