Descent formulas

[JustaNumber]

I know what you're saying, and technically you are of course correct. But in reality you aren't just going to make one mental calc and call it good for 60 miles, and just hope for the best. Things change along the way... Winds, TAS, temp, etc. So of course a good pilot is going to monitor his/her progress along the way for the crossing restriction. In the example given by the OP I would use 3:1 and begin my descent 60 miles out from the restriction. At about 30, I'd check again. I should roughly be around FL210. If no, then I'd adjust my descent rate accordingly. I'd check again at 20, and again at around 10.

VNAV or not, it's a very good idea to keep yourself in the loop. I used to fly an airplane that had more VNAV bells and whistles than most airliners out there (ProLine 21), but we still kept a check on things with a little bit of mental math.

It's pretty easy to get complacent with this stuff using VNAV and ATC in the USA, but even then there are times that you'll be left WAY too high if you're not used to quickly calculating a TOD in your head. Outside of the US, you'll definitely need to do this.

Definitely great points, and you're right about how easy it is to get complacent.

 

[BoilerUP]

The mental math for cross-check starts getting a bit complicated when you're flying into a 50kt headwind and program a 4.5° descent to a crossing restriction...but in the end, 3:1 combined with a little of that "pilot sh!t" will get ya where you need to be.

...just don't forget 1 mile for every 10kts you need to slow...

 

[platinum750]

you guys r so gay

 

[CRJ puppy]

My eyes are bleeding...

 

[Flyer1015]

How much wood could a woodchuck chuck if a woodchuck could chuck wood?

 

[JustaNumber]

Dividing numbers that large in my head makes me feel ill.

Last Transmission was broken and stupid.

you guys r so gay

My eyes are bleeding...

How much wood could a woodchuck chuck if a woodchuck could chuck wood?

It's kind of sad that when you want to talk about pilot stuff on a pilot forum, particularly math formulas in a thread clearly titled, "Descent FORMULAS", that some of the responses would be so imbecilic. Whatever happened to intellectual curiosity, or even a vague desire to learn something new or become a more-informed pilot? Trying to be cool about being a moron surprises me most, though.

 

[CX880]

It's gone

 

[wrxpilot]

It's kind of sad that when you want to talk about pilot stuff on a pilot forum, particularly math formulas in a thread clearly titled, "Descent FORMULAS", that some of the responses would be so imbecilic. Whatever happened to intellectual curiosity, or even a vague desire to learn something new or become a more-informed pilot? Trying to be cool about being a moron surprises me most, though.

I was going to refrain from further comment on this thread, but you're absolutely right. I was actually fairly impressed that we were having such a discussion on Flightinfo, then the B-team had to pipe in. It's sad really, but not surprising I guess.

Those that have been proclaiming the downfall of our profession certainly do have all the proof they need here... Aviation is starting to attract some real winners.

 

[RJLoser]

It's kind of sad that when you want to talk about pilot stuff on a pilot forum, particularly math formulas in a thread clearly titled, "Descent FORMULAS", that some of the responses would be so imbecilic. Whatever happened to intellectual curiosity, or even a vague desire to learn something new or become a more-informed pilot? Trying to be cool about being a moron surprises me most, though.

Well..... my first post was correct (not moron) and on topic. The poking took place after you came to the table with smarty pants info. Relax a little.

 

[Clutch]

It's kind of sad that when you want to talk about pilot stuff on a pilot forum, particularly math formulas in a thread clearly titled, "Descent FORMULAS", that some of the responses would be so imbecilic. Whatever happened to intellectual curiosity, or even a vague desire to learn something new or become a more-informed pilot? Trying to be cool about being a moron surprises me most, though.

Personally, this stuff is private pilot garbage. But dont let me stop you guys from impressing yourselves.