Speed Brake during descent

Hi,

 

is there a way to increase the efficency of the speed brakes during descent?

If I descending the TDS 737 with around 1500-1800 ft/min, even with speed brakes extended, the plane gets faster and faster. Finally I have stop descending, but then ATC start shouting at me.

 

Peter

 

(sorry for my bad english)

Hi,

 

is there a way to increase the efficency of the speed brakes during descent?

If I descending the TDS 737 with around 1500-1800 ft/min, even with speed brakes extended, the plane gets faster and faster. Finally I have stop descending, but then ATC start shouting at me.

 

Peter

 

(sorry for my bad english)

Your English is just fine...I do not use ATC but all I fly is the big 777 from PMDG and in descent I understand your problem but for me, for me, in descent I constantly monitor the speed and use the speedbrake and I reduce the speed manually, sometimes all the way down to idle..and continually watch the altitude to make sure I am within the range to land at my intended runway. For a few years I let the airplane do all that and it rarely worked. I always came in too high and too fast. Now, I monitor the entire descent myself and I am landing that big sucker, 777 . I apologize for not being more clear but it takes a lot of practice, at least for me , to get this process right everytime you do a flight. Also, you should read up on T/D (Top of Descent) to know where it is in your FMC and how to use it and other things in the descent process... Good Luck...

Depending on how high you are, ATC is usually too slow in giving you descent orders. They will wait until you are too close to your destination to begin your descent causing you to descend too rapidly. I will usually request a lower altitude about 150 miles away so I can do the descent less steeply. When descending rapidly, make sure you are at idle. Cycle the spoilers/speedbrakes on for 5-8 seconds then off. Rinse and repeat.

Also keep in mind you don't need to open them all the way.

 

 

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Hi,

 

...but then ATC start shouting at me.

 

Peter

 

"Please expedite your descent" is shouting? :confused:

 

Anyways I use combination of idling engines, spoilers AND flaps. And if necessary, hold hand out the window.

Anyways I use combination of idling engines, spoilers AND flaps. And if necessary, hold hand out the window.

 

I drag a foot, if necessary!;)

Flaps are never meant for speed reduction. You'll blow them off at high speed.

 

Reduce your VS, idle your throttle and use the speed break. The speed break is a variable lever.

Flaps are not used for speed reduction. They are used to maintain a level attitude and attack angle at lower speeds. Hence why they are deployed on take off and landing. That low speed means you could stall out without flaps set accordingly.

 

I should also add that you never extend the spoiler while flaps are down.

I found the same problem with this aircraft. I think the root cause is an unrealistic drag factor in the .air file. Using the speed brakes as suggested is the only way I got around it.

 

 

Best,

Phil

That probably could be changed in the aircraft.cfg and/or air file. I can't remember the program to edit air files, but you do have to know what you are doing.

 

You want a good 737? Try the PMDG 737NGX and read the manual here in the library with file name called: ngxtutorialv1.zip

1. Ofcourse flaps are used for speed reduction, but only at or below the appropriate maximum extension speeds /green arc. Actually they have two functions: increase drag, increase wingsurface to create lift while at reduced speeds. That's their purpose and why they're there. It's how we use them in real life every day.

2. Because of the increased wing surface and wing curvature when slats are extended they indeed have the effect that less pitch is needed. The angle of attack is still high as in 'not reduced', but no high pitched attitudes are needed because of the altered wingshape. So no, the AoA is not reduced, and yes the pitch attitude can be kept lower.

 

3. Ofcourse you can extend speedbrakes while flaps are down. That's what they're there for. If you didn't mess up your descend profile (you're not hot and/or high) you won't need them though. But it is possible when needed.

 

Btw, we all make mistakes and sometimes you just don't get an approach right the first time. Sometimes you're just distracted by unexpected things going on at the flightdeck or sometimes it's as simple as the headwind shifted more than anticipated.

 

My personal rule of thumb is a bit wider than the SOP. When I'm over 15 knots faster than I should be or when I'm 200 above profile at 3 NM final I go around. Most of the times I mess up an approach I'm hot ánd high by the way, if that happens I'll call it off anyway and make sure I select flaps at an earlier stage on the second attempt. That's what I feel comfortable with. Never had a controller telling me off about it.

 

As for here: relax, it's just a simulation. ;-)

 

In general: as pilot in command you're responsible for a safe and effective flight. If ATC gives you instructions you can't perform of don't feel happy to perform reply with 'unable' and give them the descent rate you are feeling comfortable with. Or pro-actively ask for a lower altitude if you need to. Heavy aircraft have more potential energy and take longer to reduce speed; we therefore have speedbrakes to handle our mistakes, not that of the controller. ;-)

There is a difference between speed brakes and spoilers in many instances. In a DC-8, spoilers aren't even operable unless weight on wheels, but the landing gear has a high speed limit to help in descent if necessary. Also, many FS aircraft only have OPEN or CLOSED positions available, which is often not the case in the real airplane. Most spoiler or speed brake systems useable in flight (especially military jets) should be able to be modulated in small increments, but are not in many FS airplanes.

 

Some planes have limits such as no spoilers with flaps extended, etc.

The DC-8 normally doesn't use the landing gear to increase drag if needed but the inboard engines in (idle) reverse. Although highly uncomfortable even max reverse can be used in flight!

My father was a UAL pilot when I was growing up. He loved the Stretch '8. I've seen him use the "reverse the inboard engines" method several times on steep descents. Works like a dream, it really does, although it tends to make the passengers slide forward in their seats a bit :D

Pat☺

1. And again, yes you use them for speed reduction

2. Flaps are not used to maintain a 'level attitude' and what means 'and attack angle at lower speeds'?

3. Wrong again.

 

 

I'm not even going to argue with someone who doesn't know about flight.

On the MD-11 you can not deploy speed brakes once the flaps are down, but it is technically possible to lower the flaps if the speedbrakes are already up. But our pilots told me that it is not advisable, since the plane will turn into something aerodynamically resembling a brick.

 

Jan

 

http://www.airliners.net/forum/viewtopic.php?t=745663

Obviously someone knows nothing about military tactical jets - incremental speed brakes are a fact of life - try making a hasty running night rendezvous without them - you'll get yelled at for taking too long to "get aboard". Also I see SWA use partial speed brakes in flight on steep segments of a STAR and seems to work quite nicely, especially once slowed down to just above flap deployment for approach.

Hi,

 

is there a way to increase the efficency of the speed brakes during descent?

If I descending the TDS 737 with around 1500-1800 ft/min, even with speed brakes extended, the plane gets faster and faster. Finally I have stop descending, but then ATC start shouting at me.

 

Peter

 

(sorry for my bad english)

 

 

They are not speedbrakes. They are spoilers.

Spoilers spoil the airflow over the wing. The air going over the wing is deflected up, and then the back of the wing no longer produces lift.

They will make you descend rapidly.

 

If it is going too fast (overspeed) then just hold the nose up, pull back on the stick.

 

Do not extend the flaps fully at that point, at that airspeed they would rip clean off. (In FSX they get damaged too.)

Do not extend the gear either. Near top speed the gear gets damaged. It will make the plane crash on touchdown.

 

To stop the plane from going too fast, simply pull the nose up. With spoilers deployed, even with nose on the horizon, you will still descend at a high vertical speed.

 

If that correction is not enough, retract the spoilers again and just deal with ATC. Learn to plan the descent better next time.

A general rule of thumb for when to start the descent is that for every 10.000ft descent, you need about 30NM.

 

You can extend the spoilers a little bit too, instead of all the way. Not easy in fsx. You can do it with the mouse, but the controls are a bit awkward, and sometimes the spoilers just shoot to "extended" position, and can't be reduced with the mouse.

To reduce them you then need to click / again to completely retract them.

I find cycling them on and off works much better then extending them a little bit.

 

https://en.wikipedia.org/wiki/Spoiler_(aeronautics)

 

Here is why you should not use thrust reversers in flight, definetly not at high speeds.

https://en.wikipedia.org/wiki/Lauda_Air_Flight_004

Thank you all for so many tips.

The recommendation from bbrz did helped me most. Extra thanks for that

 

Peter

Bbrz, we know we're right. I'm letting it rest. Goog luck! ;-)

 

 

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I think it's funny how a simple question at the beginning of this thread has turned into a heated argument about what speed brakes can and can't be used for! And this comes from a bunch of hanger pilots who have never flown an actual airplane! Carry on!

 

 

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I'm not even going to argue with someone who doesn't know about flight.

 

Be careful . . .

Thank you all for so many tips.

The recommendation from bbrz did helped me most. Extra thanks for that

 

Peter

 

Remember to set your flaps to 20 or 30 degrees at or above at least 250 knots for maximum speed reduction. In fact, turn on crash in the sim for a REAL speed reduction. I have a felling you'll learn something.

It seems to me that there is some confusion in this discussion.

"Spoiler" and "speedbrake" aren't necessarily the same thing.

A great example is the F-14, as shown below

 

 

Notice the "speedbrake" is a pair of flat plates between the engine nacelles.

The "spoilers", in this case actually spoilerons, but that's been covered, are the boards extending from the top of the wings. During flight, they function as spoilerons, helping the tail rotate the aircraft around the longitudinal axis (roll). They lift up a certain amount on one wing, depending on a ton of factors. Airspeed, roll rate commanded vs roll rate occurring, and so on.

Once the plane lands, however, they pop up to max vertical position (if the pilot commands them to) on both wings (as you can see in the picture) to "spoil" the lift of the wings, helping to hold the plane on the ground.

I'm just using this all to illustrate the difference between spoilers and speedbrakes. Having gone through all that, I believe that most modern aircraft, especially commercial birds, only have spoilers, or spoilerons, not speedbrakes. They can generally, however, use the spoilers for speedbrakes. They're just not as effective as the military plane's actual speedbrake.

It just seemed to me that the two terms were being used interchangeably, and in my limited little pea-brain, it was important to point out the difference.

Let the flames begin! :D

Pat?

I agree, Pat! I think the culprit is the 737 panel listing the spoiler arming as SPEED BRAKE.

 

These are wing spoilers on a commercial aircraft along with flaps deployed.

 

These pictured below are military aircraft with SPEED BRAKES/AIR BRAKES deployed! The A-3 ain't doin' so hot! If I remember right, the default Mooney has a deploy-able speed brake.

 

 

 

@mrzippy. On the first pic the plane is already on ground and using the spoilers together with the flaps always happens after touchdown.

What's nice to see on this pic is the high extension angle and the fact that all spoiler panels are extended.

It's quite obvious in this picture that extending these during flight would create way too much drag and loss of lift.

 

This is why I tend to cycle them for a short duration to slow my descent if ATC has me too high for my approach. I watched this in action on a 757 descending fairly rapidly into KJFK. He was on a steep approach and in a turn and was cycling the spoilers.