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WebMaximus

Heavy use of speedbrakes and their effectiveness

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Hi fellow NGX drivers!

 

I've found myself having to use the speedbrakes pretty much on every descent/approach I do when complying to ATC instructions and flying most of the descent using VNAV and I also think the speedbrakes are not that effective.

 

I know this has been discussed before but just wanted to ask what the final verdict was, is the speedbrake's effectiveness in the NGX on par with the speedbrake in the real NG?

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The 737NG is like an arrow when it's descending. The trick is to decrease thrust prior to your descend initation. However, I get to use the speedbrakes pretty often too.

 

A buddy of mine who flies the NG in real life told me once that his company even flies almost whole descends and approaches with ILDE thrust, from FL380 down to the runway.

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I fly the 737-800 NGX and it's as slippy as a wet seal. If I'm not ahead of that plane by at least five minutes it eats me up on descent. I use a descent calculator that takes into account descent altitude, head/tail winds and speed decreases to determine TOD ... I compare this to VNAV to see when it is a good idea to descend. Just for fun I've ridden the VNAV all the way down for a test and it has never put me on final approach at a low enough energy state so that I'm landing Vref+5knts. I have to use V/S, LVL CHG and SPEED INTERVENE in combination to adhere to ATC requirements ... I've also tried to enter in highly conservative speed decelerations into VNAV and when I do it correctly, I'm still using the Speed Brake.

 

I have an eleven page document that takes this bird from cold and dark to tuchdown ... bullet pointing every step inbetween. I'll send it to you if you would like © (T) (Blankenship) AT GeeMail DOT com. I've spent hours and hours watching Angle of Attack videos, reading the tutorials and taking instruction from the great pilots at Southwest Virtiual Airline ... it is in its second revision and I'm getting real close to being satisfied with it. I'll also send you my descent calculator (Excel spreadsheet) ... unless I've already done so and I've forgotten about it (getting old ya know).

 

I was in the US Navy and we visited Stockholm ... we went to a club called The Daily News ... I swear those Scandinavian girls were (are) simply stunning <s> ... oh ... and it had NOTHING to do with being cooped up on a ship with 250 dudes for three months.

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There's a thread every week on some subject like this.

 

No, the real jet will go from TOD without riding the speedbrakes the whole time.

 

Sometimes the jet will get a bit fast, but just as often you'll need to add power.

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It also depends on your inputs as a pilot. If you input the enroute winds correctly, and keep your mind ahead of the plane, everything should be just fine.

Having said that, the 737, and especially the -800, is slippery as hell in real life. You really need to manage the energy, especially at higher weights.

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yea Speedbreaks are used a lot in 737 but not the whole descend, last january i was on a trip and weather was choppy on descend i was seated right on the wing, and the pilots where using the heck out of the speedbreaks

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There's a thread every week on some subject like this.

 

No, the real jet will go from TOD without riding the speedbrakes the whole time.

 

Sometimes the jet will get a bit fast, but just as often you'll need to add power.

 

Ok, if that's the case I'm surprised this fact wasn't found during beta testing or fixed in one of the service packs after it was released.

 

Well, thanks anyway for all input guys!

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Ok, if that's the case I'm surprised this fact wasn't found during beta testing or fixed in one of the service packs after it was released.

 

Well, thanks anyway for all input guys!

 

Hi Richard,

 

It's a good thing you're not flying the A321. It's more slippery than the 737-800wl. When heavy you will find yourself with greendot speed above Flap 1 speed. And extending speedbrakes on it will just raise VLS to above Flap 1 speed also. Very trickery....

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I hardly ever use the speed brakes.. Only when the route ATC gives me is whacked, might

I need em. I might use em maybe once in every 20-30?? flights.. Not very often.

As along as the approach is fairly normal, I don't need em.

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Im using it often, because when im descending i will descend fast and the speedbrakes are required for it. Also im using lvl change at higher levels so the plane will descend more than 1000 feet per minute. I like it,

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Hi fellow NGX drivers!

 

I've found myself having to use the speedbrakes pretty much on every descent/approach I do when complying to ATC instructions and flying most of the descent using VNAV and I also think the speedbrakes are not that effective.

 

I know this has been discussed before but just wanted to ask what the final verdict was, is the speedbrake's effectiveness in the NGX on par with the speedbrake in the real NG?

Real 737 speedbrakes are not very effective, so I think the NGX speedbrakes are probably realistic. FSX pilots are used to the unrealistically effective speedbrakes in other planes.

 

When I fly the NGX I don't use speedbrake much in descent, partly because I know they won't be much use. The key is looking ahead at where you want to be at what speed, not letting VNAV do your thinking for you. It isn't perfect.

 

As for the NG being slippery, it is no more slippery than more modern designs. It's more slippery than older 737s though.

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Ok, but with thrust at idle and speedbrakes fully extended is a 1000-1200 ft/min descent rate realistic?

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I usually descend at 2000-2200 with no speed brakes when I'm in the early stages of

the descent. I'll be close to idle, but not always.. Rarely do I need to put the brakes on.

Like I say, only if ATC gets whacky with me, and puts me high and fast, do I use em.

Doesn't happen too often.. Every once in a while it'll happen..

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Recently I've found myself sat with 50-100% speedbrakes on approach to Heathrow. The approach height restrictions (7000A and 6000A) continue until very late in the STAR meaning I have to descend ~3000ft in a couple of miles. I would guess that I'm just going too fast (mostly just using LNAV and VNAV) until 8000ft. Not flying online so no ATC instructions.

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Ok, but with thrust at idle and speedbrakes fully extended is a 1000-1200 ft/min descent rate realistic?

 

Well, that's very much dependent on your airspeed,of course. The lack of that bit of information makes answering your question rather difficult...

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Ok, but with thrust at idle and speedbrakes fully extended is a 1000-1200 ft/min descent rate realistic?

That or more for a minimum.

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Mostly I find myself in a situation where I'm having trouble slowing down when descending below 10k where you're normally have a speed restriction of 250 knots and flying in VNAV mode the FMC wants me to be even at 240 or less and to keep below this speed my decent rate at idle thrust and with fully extended speed brakes is approx 1200 feet/min often resulting in coming in too high.

 

Guess I'll have to start planning more myself rather than trust the FMC and the VNAV mode.

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Speed Brakes are not Required if you are flying within VNAV PATH as it is calculated with speed brakes down. But when ALT Restriction are so closed that the current drag is not enough to comply with the restriction the Speed Brakes will be needed.The descent rate with speed brakes up will depend on aircraft Gross Weight. The best way to descent when ATC doesn't give your descent clearance at T/D (i haven't seen this on fsx) is to select DES NOW on VNAV DES page if you are before T/D (it will descent at 1000ft/m to intercept VNAV PATH. If ATC request you to expedite your descent this is not an option) or Descent as fastest as you can go (no need to use speed brakes) if you are after T/D until intercepting VNAV PATH.

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I don't see that problem too much even VNAV.. Every once in a while, but not very often.

There should be a decel point before you start getting too close. It's usually at a point

where you have plenty of time to get it slowed down by the time you get to the airport.

And if following the normal flaps sked, the FMC should keep reducing the speed as you

go along.

Only when I get a FMC plan that is whacked for some reason, have I ever had a problem

with that. But I do descend semi manually most of the time. I'll run LNAV/VNAV until I get

close to the FMC planned TOD, and right before that, I switch to MCP speed and ALT.

And the rest is pretty much dialing in what I want manually, according to what ATC tells me.

 

The ATC TOD will usually be slightly different from what the FMC wants to do.

So from that point, VNAV is a goner.. I keep running LNAV until ATC starts steering me,

and then it's off too.

I usually start most of my descents at about 2200 fpm, and I gradually shallow up a

bit as I get closer to dirt. I'll usually be descending at about 1200-1400 fpm when passing

through 10k, and even shallower as I approach the ILS.

But.. I'm sure I'm not exactly following any specific airline, and I don't have anyone

telling me how to fly. So I get to make my own rules.. I'm so used to the ATC routes I

use, I know what fits the best. lol..

 

But I can set it up and fly LNAV/VNAV from 400 ft, all the way to an autoland, and usually

don't have any trouble.

Course, I'm usually playing Southwest buoy, and they don't do autolands. Pretty HGS

driven.. I can land in fog so dense you can't see the runway lights just using the HGS

and flying by hand.

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Make sure you are inputting descent winds into the FMC, so it can adjust TOD for headwind/tailwind, also what makes a great difference is whether you have to have eng anti-ice on during the descent. Input those values and see how it works out. You will still need to use speedbrakes for fine tuning, unforecasted conditions, etc...

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Make sure you are inputting descent winds into the FMC, so it can adjust TOD for headwind/tailwind, also what makes a great difference is whether you have to have eng anti-ice on during the descent. Input those values and see how it works out. You will still need to use speedbrakes for fine tuning, unforecasted conditions, etc...

 

You are right, i have seen that when i'm descending with tailwind, the aircraft go off path and i have to apply speed brakes to go back on path.

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Thanks again guys for lots of great input and tips, I'll take all good advice with me and hopefully that will help me lessen the use of speedbrakes.

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240 or less and to keep below this speed my decent rate at idle thrust and with fully extended speed brakes is approx 1200 feet/min often resulting in coming in too high.

You should be closer to 2200fpm at 240knots with S/B and clean.

 

The NG can overspeed/go to VNAV SPD at the TOD above FL350.

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Exactly and that's what makes me wonder why my NGX most of the times won't do more than approx 1200 ft/min regardless of head or tailwind. One thing though is of course the use of TAI on most flights this time of year in Europe where I do most flying.

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