X-ing restrictions

[Knob]

I used to use the ALT to lose * 3, GS * 5 to make crossing restrictions in the EMB-120, however this can lead to descent rates of 3000 fpm or more in the ERJ. What other methods (besides the FMS) are you people using out there? Thanks.

 

[Nindiri]

The FMS is the only way to go in the CRJ. I let it show me a 3 degree descent and I use the VS to execute it. Fuel efficient and smooth ride for the pax.

 

[Sgt. Hartman]

I use altitude to loose X2 and I just keep track of my progress as I go. eg. 60 miles out at 30000 40 miles out at 20000 etc. If you get a little high or low on the profile adjust the rate of descent accordingly.

sgt.

 

[Blueridge]

If you need to do over 3000 fpm on a 3 degree descent, that implies you're doing over 600 kts gs. I'm guessing the math is screwed up somewhere. At my company, we use:

alt to lose / 3 = miles req. for descent.
rate of descent = ground speed * 5 (or 1/2 the gs and add a zero)

For example, you're at FL250 and told to cross XYZ at 110 and you're doing 440 kts gs. We would begin our descent 47 miles from XYZ and hold 2200 fpm on the way down. Assuming the winds don't change with altitude, you should be spot on with the crossing.

Hope this helps,

BR

 

[rstev1955]

I find 2000fpm is normally fairly close to a 3 degree glidepath from altitude and is a smooth ride for the PAX. It is easy to just take half of the altitude you need to lose (in thousands) and start down that many minutes before the fix. If you also need to slow down, i.e. 10000ft and 250K then start down a minute earlier.

As long as you keep updating how many minutes to the fix, you can make minor adjustments to cross it right on altitude and/or speed. The only thing you have to watch for is a decreasing headwind as you descend, which will get you to the fix quicker than you originally planned.

Another good techinique in the RJ is if you have been given an alititude below 10000ft then descend at 310K and whatever descent rate you want. When you get to 12000ft, use idle power and 1200fpm. you should get to 250K just as you are approaching 10000ft.

Cheers.

 

[Captain X]

I used to use the ALT to lose * 3, GS * 5 to make crossing restrictions in the EMB-120, however this can lead to descent rates of 3000 fpm or more in the ERJ. What other methods (besides the FMS) are you people using out there? Thanks.

How often do you see 600 Knots GS in the ERJ?

I can say i've only seen it only once or twice while descending on the "steeper" parts of an arrival into in the winter with some kick ass tailwinds.

Most of the time though I never see a descent rate in excess of 2500 FPM using the very method you describe.

Alt to Lose X 3 for distance TO BE ESTABLISHED in the descent.

Add 1 mile for every 10 KIAS above 250 (if there is a speed requirement)

Groundspeed at TOD X 5 for Rate of Descent.

Ex. FL370 to cross a fix at 10K and 250 KIAS, current ground speed 500 Knots

37-10 = 27 X 3 = 81

320 KIAH -250 KIAS = 70/10 = 7

81+7 = 88 miles out (round up to 90)

500 KTS GS X 5 = 2500 FPM

600 KTS GS would be 3000 FPM.

650 GS would be 3250 FPM

You'd have to see 700 to get to 3500 FPM

Been working like a charm for the last 5 years and never had a pax complain or felt like I was "rushing" to make a restriction.

 

[Caveman]

I put the little pink banana thingy in front of the fix and go back to reading the paper.

 

[EMB170Pilot]

Vnav or use time from FMS to the next waypoint and use 1,000 fpm or 2,000 fpm whatever...no problems

 

[CitationLover]

why are you complicating your life? use the FMS. do you make mental notes and mental gyros when flying the needles? use the FMS, it is a tool for you to use.

 

[Captain X]

use the FMS, it is a tool for you to use.

As is the grey matter 'tween your ears that you will rely on when the box takes a dump. Helps to keep it tuned up and runnin' right....

Now where'd I put that Gingko Biloba?