Calculating Top of Descent Point | Descent Planning Rules of Thumb 

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

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

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!

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

One of the best explanations ever

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.

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?

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.

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.

I think you really made this more complicated than it needed to be. Even King Schools isn't this convoluted.

0:50 doesn't work for 'any' aircraft. There are gliders that need a lot shallower descent than that. That approximation is like 1 to 20ish where as gliders need 1 to 50 and some 1 to 75. I can imagine helicopters and fighter jets as well as space shuttle and many other 'aircraft' need a different formula.

Super clear ! Well explained. Good job 👏🏻

Holy smokes this content is so good I feel like I’m stealing. You guys rule.

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.

I usually do similar to the second method. How much altitude will I need to lose? At a 500fpm decent (easier math than my usual 700fpm), how long will it take? Within 5 minutes of that time, start cruise descent.

Gotta love these tips n tactics.

How do you include the “curve” of the spinning globe in your calculation???

Your vids prove the best!!

Thank you for great formulas. Very very usefull when FMS profile calculation is inoperative ;))) So, taking into consideration that we fly JET with 400 knots ground speed at initial descent, our vertical will be 2000 feet per minute, arriving to the airfield within 200 knots we decrease it to 1000 to stay with our 3 degrees profile. Is it correct ?

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.

1:00 hahaha 😂Great video!

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 ?

Thank you.

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

Great video

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..

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

I love you you make everything so do able

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.

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

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!

arc tangent not cotangent

On behalf of every sane person on this globe, I feel truly sorry that your informative video has been twisted into proving that the Earth is flat, by some con-man.