Mental math for crossing restrictions..??

[tathepilot]

I'm looking for a few formulas..

 

[Snapshot]

3-to-1 works well on descent.

Three miles for every thousand feet you've got to lose.

10,000ft will take you 30 miles. Adjust 1 mile for each 10kts of wind.

15,000 ft to lose with a 20 kt headwind will be 43 miles. (15x3) -2

 

[RP170]

I'm looking for a few formulas..

You can take the altitude you need to lose divided by 1000 and multiply it by 3.

Example:

You want to descend from FL350 to FL200. Take 15 x 3 = begin descent 45 miles out.

Multiply your ground speed by 5 to determine the approximate ft/min descent rate for a 3.0 degree glide path.

 

[bluefishbeagle]

When you get the crossing restriction:

1. Flight idle
2. Spoiler extend
3. MMO or VNE whichever is less

At any time if Center asks if you can make it:

1. Say "no problem"
2. Gear down
3 Flaps extend
4 Pray.

Never missed one yet

 

[tathepilot]

When you get the crossing restriction:

1. Flight idle
2. Spoiler extend
3. MMO or VNE whichever is less

At any time if Center asks if you can make it:

1. Say "no problem"
2. Gear down
3 Flaps extend
4 Pray.

Never missed one yet

Yeah, huh..

 

[BushwickBill]

I'm looking for a few formulas..

Groundspeed add a zero /2 gives you 3 degree glide path.

400 knots = 4000/2 = 2000 fpm for a 3 degree decent

Altitude to loose 410 to cross "BAILL" at 11,000

30,000 / 2000 fpm = 15 minutes out from your crossing restriction begin decent.

Or you can press VNAV on the G530 and it will do it all for you.

 

[Papps]

Groundspeed add a zero /2 gives you 3 degree glide path.

400 knots = 4000/2 = 2000 fpm for a 3 degree decent

Altitude to loose 410 to cross "BAILL" at 11,000

30,000 / 2000 fpm = 15 minutes out from your crossing restriction begin decent.

Or you can press VNAV on the G530 and it will do it all for you.

I don't think about it in minutes but i do something similar.

410 to cross baill at 11000. 30000' to loose thats 90miles out.

If im averaging 400 knots GS I add a zero to 400 (4000) then divide by 2. 2000fpm

so 90miles from baill i start a 2000fpm descent.

 

[tathepilot]

You can take the altitude you need to lose divided by 1000 and multiply it by 3.

Example:

You want to descend from FL350 to FL200. Take 15 x 3 = begin descent 45 miles out.

Multiply your ground speed by 5 to determine the approximate ft/min descent rate for a 3.0 degree glide path.

I like this one, I'll give it a shot tomorrow..

 

[tathepilot]

.................

 

[tathepilot]

I don't think about it in minutes but i do something similar.

410 to cross baill at 11000. 30000' to loose thats 90miles out.

If im averaging 400 knots GS I add a zero to 400 (4000) then divide by 2. 2000fpm

so 90miles from baill i start a 2000fpm descent.

If you get a crossing restriction when you are 90 miles from the fix, are saying that you start a descent as soon as you get the restriction..??

BushwickBill used 90 miles as an example of when he got the crossing restriction. How does 90 miles fit into your example..??