What's the best way to do a steep descent in the NGX? Say I'm flying level at 16,000 feet, at 240 kt, no flaps, and want to descend as quickly as possible to 3000 to pick up an ILS. (I know about planning ahead, but some STARS require a sharp descent in a limited distance.)

 

If I set 3000 in my altitude window and click LVL CHG, the descent is too slow for what the STAR requires. But if I click VS and set a faster rate of descent, my speed shoots up to 300 kt or more, which will also be a problem. Strangely, if I activate the speed brakes, the speed seems to rise even higher.

 

What am I missing?

 

Tom Kent

Rapid descend tehnique described on FCTM 7.5.

 

But if I click VS and set a faster rate of descent, my speed shoots up to 300 kt or more, which will also be a problem.

 

Don't use V/S, better set LVL CHG and set VMO/MMO. IIRC .82 and 340kt.

If needed you can drop tha landing gear down, just watch speeds limits.

A lot depends on the plane you are using. Some planes are slipperier than others.

 

Remember the rule: at 30 miles out, you need to be lower than 10,000 feet and slower than 250 kph.

 

Sometimes I wonder how seriously the 260 kph speed limit between 10,000 feet is taken in real life. When I look at actual flights on Flightaware.com it seems that many planes are coming in much faster than that. (Flightaware.com has graphs showing the speed and altitude of real world flights at relatively short intervals) Perhaps Flightaware.com is recording something else, like groundspeed or mph? But in any case, real world planes seem to be coming in pretty fast.

 

I have found that in most planes, the speed brakes slow me down to 220 kph in pretty short order, although the plane's descent slows markedly for a few seconds. Once 220 kph is reached, the plane does not slow down much more.

 

I have developed my own practice, which may or may not mimick real life practice. First, I tend to use relatively steep descents of 2,500 fpm. This seems to approximate the descents I am seeing on flightaware.com. As I approach 20,000 feet, I set my speed to 250 kph. As I approach 10,000 feet, I set my speed to 220 kph. As I approach my approach altitude, I am down to 200 kph, and after getting my final instructions, I slow down to my landing speed. (typically around 140 kph). As I slow down, I start extending the flaps (often using the F8 key) until they are fully extended. After getting the final instructions, I turn to the directed heading, then switch to the locator/NAV, and when the ILS is within a dot of where it needs to be, I go to the APP button.

 

This routine is the result of a lot of experimentation, although I have not really fine tuned it.I don't know if this is how real world pilots do it, but it does mimic to some extent what I have observed on the graphs at flightaware.com -- except the real world pilots seem to be coming in pretty fast. It does work for me most of the time. If I follow it, I seldom have to use speed brake and almost never dind myself coming in too high and too fast. For those airports where the ILS is not working, I can do my glideslope manually with a descent of about 800 fps. When I don't follow this routine, I often end up doing a missed approach because I am coming in too high and too fast.

 

No one ever seems to give actual numbers or settings, but just general, and usually useless, advice. It's why I have put actual numbers down in this post. It may take some fine tuning and experimentation depending on the plane you are using.

 

Sometimes it seems like a hobson's choice where you can (1) not descend fast enough, fly over the airport too high and do a missed approach, (2) forget about the speed limit, (3) make extensive use of the speedbrakes and waste a lot of energy. Pick your poison.

 

Anyway, my two cents.

Could you provide an example of a STAR that has a "sharp decent?" Going from 16000 down to 3000 would lead me to believe you missed something on the chart.

 

Willy

ZIGGY4 at KONT has a steep descent to an ILS that the first generation NG couldn't handle. The MD-11 figured it out and I assume the NGX does it quite well too. The key is slowing down, steep angles are acheivable with lower ground speeds. Entering the arrival over HEC with an IAS of 210 makes it look easy.

Sometimes I wonder how seriously the 260 kph speed limit between 10,000 feet is taken in real life.

 

The speeds you see on flightaware (and what controllers see) is groundspeed derived from the radar information. The limitation (in most jurisdictions) is 250 KIAS or slower. Note it's Knots Indicated Air Speed, not kilometres per hour. Well...in most places. Russia, China, and lots of other CIS countries being the metric examples.

Metric speeds? I have never heard about that, are you sure they use that? On a different note, ATC will some times instruct planes to fly faster than the 250kts limit below 10 000, to expedite traffic / help maintaining separation. But its not the norm

ZIGGY4 at KONT has a steep descent to an ILS that the first generation NG couldn't handle. \

I do real life ONT to SJC back to ONT 3 times a month on southwest. After you get past the hill going in to ONT the speed breaks always come to full and sometimes the landing gear. Its a fun approach to fly. I know it like the back of my hand.

ZIGGY4 at KONT has a steep descent to an ILS that the first generation NG couldn't handle. The MD-11 figured it out and I assume the NGX does it quite well too. The key is slowing down, steep angles are acheivable with lower ground speeds. Entering the arrival over HEC with an IAS of 210 makes it look easy.

 

I'm not sure what the the NG couldn't handle with ZIGGY4. Obviously, landing on 8L/R more time/distance to get down, but if you were trying to just follow the magenta line with one click of the mouse and fly straight in to 26, sure it is steep. But if you actually read the chart you would notice that there is a holding pattern published on the arrival at PETIS. Also take note of the MEA's, "expect clearance to cross at 12000" does not stop the PIC from requesting lower.

 

Willy

I'm not sure what the the NG couldn't handle with ZIGGY4. Obviously, landing on 8L/R more time/distance to get down, but if you were trying to just follow the magenta line with one click of the mouse and fly straight in to 26, sure it is steep. But if you actually read the chart you would notice that there is a holding pattern published on the arrival at PETIS. Also take note of the MEA's, "expect clearance to cross at 12000" does not stop the PIC from requesting lower.

 

Willy

The holding pattern is never used, a good pilot is able to bring the plane in to land.

The holding pattern is never used, a good pilot is able to bring the plane in to land.

 

Still does not negate the fact that it IS published on the chart and available to be used if necessary. A good pilot starts with being able to read and comprehend the information published on the chart. Proper planning is what allows the pilot to bring the plane in to land, NOT their ability to shove the yoke thru the panel.

 

Willy

Still does not negate the fact that it IS published on the chart and available to be used if necessary. A good pilot starts with being able to read and comprehend the information published on the chart. Proper planning is what allows the pilot to bring the plane in to land, NOT their ability to shove the yoke thru the panel.

 

Willy

A good pilot is able to use all resources available.

A good pilot is able to use all resources available.

Exactly! Holding at PETIS would be considered a resource available, whether they do or not.

Look, my point here is that the OP is clearly doing something wrong if they are trying to go down from 16000' to 3000' while trying to get established on the LOC and rather then say it, I asked for the STAR they were referring to. Dan had mentioned ZIGGY4 and stated the NG (i assume he meant the first PMDG release) couldn't do it. After looking at the chart, the only reason it would not be able to do it would be because the info is not entered into the FMS for what the aircraft can do. If you select a STAR on the FMS, by default it would set up the aircraft to cross DAWNA at 12000' and in excess of 250kts because you are above 10000'(by default in NG/NGX). The "good pilot" on the airline you refer, more then likely are not steaming ahead at 250+kts crossing that intersection and would properly program the FMS to meet the decent profile desired. whether it be descending down to the published MEA's, reducing speed sooner(as Dan correctly pointed out) or both. Holding at PETIS is still a viable option, especially if there were conflicting traffic not allowing a "good pilot" to maintain the desired decent profile. Bottom line here is, don't assume that all is good because the approach is in the NGX data base.

 

Willy

you could always "slip" down by crossing over your controls, eg left aileron .right rudder and wont affect your airspeed but Vertical speed is enormous

one problem, you will have 150 full sick bags..

you could always "slip" down by crossing over your controls, eg left aileron .right rudder and wont affect your airspeed but Vertical speed is enormous

one problem, you will have 150 full sick bags..

 

Never ever cross controls in a jet. It's extremely dangerous.

To get down quickly all that is necessary is to pull the speed brakes out. A good daily example of this is coming over the Alps into Torino Casselle. The descent is from FL230 to 4,500ft in about 15dme. Throttle back to 210 kts and apply full spoilers. Your descent rate will be above 2000fpm and fully under control. And, safe!