Heavy use of speedbrakes and their effectiveness

[MMartinov 48]

Is the approach speed containing an issue or feature?...

 

I would say rather feature. My 2 cents to address it:

• Use lower CI (20-30). Unless there is strong tail wind, you should be able to fly the whole descent on VNAV and no speedbrakes will be required.
  
• High CI will result in late TOD calculation, theoretically ending up with higher speed on your lower portion of the descend.
  
• The descend rates are much better when flying fast in the upper portion of the descend profile.
  
• Use your FMC. Load all predicted winds, as well as if you expect to use EAI.
  
• Check all altitudes in the legs page, configure the STAR as per the charts - speeds, altitudes.
  
• Finally if you end up using DIRECT, the use of speedbrakes is inevitable so better use it early.
  

[VIPERGTSR01 22]

I don't use the speedbrakes very often unless ATC holds me up below 10000ft or if I get unexpected tail wind and am using TAI (below 10,000), then the idle descent rate can be horrible. At this point I usually almost level off and dump speed deploy some flaps (max 5 unless on final) and try to get back on path.

 

I use a low CI (usually 15) and if I am above VNAV path and comfortably above the 250/10000 restriction I just use speed intervention and speed the 800 up, no problems getting back on glidepath. So the only time I use speedbrakes is below 10,000ft really and even then it usually isn't for long.

[killkenny1 22]

I get normal descend without anti ice on (no winders here, FMC calculates for AI off). Few things I do (separatly or together) to get to a normal descend without using speed brakes (I still have to use them sometimes, but not too much):

Correct one would be to program Forecast page under Descend. Put in AI on/off altitudes and you're pretty much set for the most time. Problem here for me lies in the fact that I mostly have to guess where clouds are/will be. I have to look into OpusFSX settings...

Other method I sometimes use is flying a longer STAR (if available).

On shorter flights, when I fly at around FL130, I drop my speed to around Flaps 1 before descending.

Those are the main ones I use. There are other methods too, try experimenting!

 

But on the hot sunny days -800 drops pretty well.

[James Bennett 52]

I rarely have to use speedbrakes to descend, using LVLCHG i can descent at a comfortable rate of descent and the A/T will hold the desired speed, provided it is reasonable and i haven't input something drastically low.

[Spin737 102]

is the speedbrake's effectiveness in the NGX on par with the speedbrake in the real NG?

To answer the original question, you should get about 900fpm more descent at high speed (~M.74) and about 300fpm at Vcl in the real NG.

 

Compare that to the NGX, and there's your answer.

[FirstOfficera320 1]

Very interesting you mention this because I've noticed that too and on occasions this fact has tempted me not to use TAI especially when it still won't do any real difference in FSX where no icing conditions are simulated at least not with the NGX but trying to fly as close to real world ops as possible it still feels wrong not using TAI flying in conditions where you would IRL.

 

This can't be totally correct or is it like this in the real bird too?

 

 

 

Thanks for your tips and interesting feedback!

 

When you say you used V/S descending @ 3000 ft/min were you also able to do that below 10k keeping the speed below 250 knots?

 

I heard before the 800WL is the most slippery one and I do all my flying in that model so guess that's adding to my problems coming in too hot on many approaches.

 

It certainly isn't correct to not have the Ilde speed not roll back.

 

It was only the first 10000feet or so that I did at -3000fpm. At that point I was back on my pencil "vnav" path. Thus keeping the vertical speed at ground speed times 5. In other words a 3 degree decend. The airspeed was around 315kts at it's highest getting back to 283kts.

 

From FL100 at 240kts I was doing a resonable 1200fpm, which I find realistic. Engines at idle from TOD to 1800 AGL.

 

May the force be with you

[EdubFlyer 2]

Something I noticed when using engine anti-ice is that when switching it off again (for example when breaking through the clouds or when outside temperatures are high enough), engine thrust does not return to flight idle, but stays at the slightly increased level associated with the use of TAI. Only when I tap F1 or wiggle my physical throttle a bit (that sounds wrong, I know), and then fully close it again, does the N1 thrust return to its normal value. This might be affecting your flights as well, possibly.

 

I've started a thread on a similar topic that was never really answered (or maybee I didn't explain the issue properly). Basically when you descend from above 30,000 the n1 is higher then at around 30k the idle will drop. I think they are simulating the windmill effect on the engines at higher speeds. Same as if you turn TAI on, the idle level needs to rise to maintain bleed pressure. In the NGX when these things occur you will see the throttle levers move up or down slightly in the virtual cokpit to create this effect. I don't think this would happen in the real plane , just an effect in the modeling to simulate this. I use the good old Microsoft FF2 joystick. The cure that I found is when I press the TO/GA button at takeoff, I also advance the throttle full foreward and and don't touch it again until I need to disconnect the A/T. This is the opposite of what is suggested in the tutorials ( or at least my interpretation). If I do that descent is a lot more predictable and the engines seem to behave properly when TAI is switched on and off.

 

Eric