c5load
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Full Flap Landings

Sun May 24, 2009 1:51 am

Do airlines use FULL flap landings? The trips I have flown on civilian-wise i watch when they put the flaps down, and I have never seen them down fully, they are more like halfway. Any ideas or do they always use them full?
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BMI727
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RE: Full Flap Landings

Sun May 24, 2009 2:06 am

I think that most, if not all airliners can, but only some do. A 737 for example can use flaps 40 to land, but 30 is used most often if I'm not mistaken. I think that generally there are several flaps settings that can be used on landing, or takeoff for that matter.
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Mir
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RE: Full Flap Landings

Sun May 24, 2009 2:08 am

Some do, some don't. It depends on the airline, the airplane, and the situation.

They will be more than halfway down, though.

-Mir
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eghansen
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RE: Full Flap Landings

Sun May 24, 2009 2:21 am



Quoting Mir (Reply 2):
Some do, some don't. It depends on the airline, the airplane, and the situation.

Pilots seem to use a lot of flap when landing in San Diego. The runway is short with a displaced threshold, there are obstructions all around and water at the end of the runway. There are also no high-speed turnouts from the runway. I have seen may flights go-around at this airport as well.
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c5load
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RE: Full Flap Landings

Sun May 24, 2009 2:24 am



Quoting Mir (Reply 2):
It depends on the airline, the airplane, and the situation

Wouldn't it make sense to use full flap in order to make sure you are going slow when you cross the threshold, then you wouldn't have to use as much brake nor t/r right?
"But this airplane has 4 engines, it's an entirely different kind of flying! Altogether"
 
cvervais
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RE: Full Flap Landings

Sun May 24, 2009 2:38 am

I think the most amazing full flap landing I've seen was in a AA 772 landing at SJC. I was in seat 31A and I was amazed how low the flaps went. It was great.
 
Mir
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RE: Full Flap Landings

Sun May 24, 2009 2:47 am



Quoting C5LOAD (Reply 4):
Wouldn't it make sense to use full flap in order to make sure you are going slow when you cross the threshold, then you wouldn't have to use as much brake nor t/r right?

Yes. It also increases drag, which increases the thrust required on final, which increases noise (makes nearby residents unhappy) and fuel burn (which makes the airline bean counters unhappy). So if you have a nice long runway where you don't need to stop in a hurry, it might make sense to use a lower flap setting.

-Mir
7 billion, one nation, imagination...it's a beautiful day
 
N62NA
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RE: Full Flap Landings

Sun May 24, 2009 2:56 am



Quoting Cvervais (Reply 5):
I think the most amazing full flap landing I've seen was in a AA 772 landing at SJC. I was in seat 31A and I was amazed how low the flaps went. It was great.

Ditto. Whenever I don't get any upgrades on AA 772s, I pick row 27 which is right behind the wing and man, those flaps sure do extend far during landing!
 
ZBBYLW
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RE: Full Flap Landings

Sun May 24, 2009 3:03 am

The DC-10 actually has an impressive amount of flap! If by full flap you mean 90 degrees, no aircraft (that I know of) uses that much. Commonly the most you will see is 60 and those are rarely used. It will depend on the situation as to how much to use.
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rfields5421
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RE: Full Flap Landings

Sun May 24, 2009 3:38 am

If they have enough runway, most planes will try to maintain a certain speed until over the threshold - to keep the pattern and separation for different types even.

But I'd bet all jets use full flaps at places like SBRJ - Santo Dumas - places with 4,000 - 4,500 foot long runways.
 
chrisjw
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RE: Full Flap Landings

Sun May 24, 2009 3:47 am

Does anyone know which airplane has the highest flap setting possible?
 
mpdpilot
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RE: Full Flap Landings

Sun May 24, 2009 4:07 am

I wanna say there is a Federal Aviation Regulation that says that pilots should use the least amount of flaps to make a safe landing. Don't quote me on that though I don't recall where I read that.

When your landing on a 10000' runway you have plenty of room and no need to stop super quick. Whereas on a shorter runway full flaps are required just to stop on the runway. It just kind of depends.
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stillageek
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RE: Full Flap Landings

Sun May 24, 2009 4:19 am

On the CRJ700 we always use Flaps 45 for landing...every landing...every runway...every condition. On the ERJ's at my airline they are approved for reduced flap landings...I think they can land at flaps 22 instead of 45.
 
phxpilot
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RE: Full Flap Landings

Sun May 24, 2009 4:41 am



Quoting Stillageek (Reply 12):
On the CRJ700 we always use Flaps 45 for landing...every landing...every runway...every condition

Are you sure you don't use Flaps 20 for single-engine approaches?
 
modesto2
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RE: Full Flap Landings

Sun May 24, 2009 4:58 am

At my airline, we generally use full flaps (flaps 45) when landing the EMB145. At one point, the airline started an initiative to use flaps 22 landings as a method to save fuel with lower power settings on final approach. However, brakes wear obviously increased with the higher approach and landing speeds so eventually, the policy reverted to the original flaps 45 practice. Now, we mostly use flaps 45, but certain circumstances like strong crosswinds or high potential for windshear may dictate a flaps 22 landing.

I sit in a lot of 737 and 757 jumpseats and as others have said, most 737 landings use flaps 30 while the full flap setting is flaps 40. The maximum 757 flaps setting is flaps 30 and most 757 landings that I've seen use this setting.

As a general rule of thumb, most operations dictate full or close to full flap settings for landing, but operational considerations may dictate otherwise.
 
tdscanuck
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RE: Full Flap Landings

Sun May 24, 2009 6:21 am



Quoting Chrisjw (Reply 10):
Does anyone know which airplane has the highest flap setting possible?

Do you mean highest = highest number, or highest = highest deflection? It's been a long time, for some OEM's, since the flap setting actually corresponded to the flap angle in degrees.

Tom.
 
vikkyvik
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RE: Full Flap Landings

Sun May 24, 2009 8:11 am



Quoting Eghansen (Reply 3):
Pilots seem to use a lot of flap when landing in San Diego. The runway is short with a displaced threshold, there are obstructions all around and water at the end of the runway. There are also no high-speed turnouts from the runway. I have seen may flights go-around at this airport as well.

I wouldn't classify SAN as having a "short" runway. From the displaced threshold, you still have over 7500 feet of landing distance. With a typical 950 foot glide, that's 6500 feet of landing rollout distance.

Airliners, for most intents and purposes, can stop on a dime if needed. That's relatively speaking - taking into consideration how little actual braking surface they have compared to their weight. Airliner wheel brakes are worked extremely hard, and they do an amazing job (consider how much energy they have to absorb to actually stop an airplane).

Check out the FAR landing distances for the 747-400 (starts on the 36th page of the PDF):

http://www.boeing.com/commercial/airports/acaps/7474sec3.pdf

Notice that at Maximum Landing Weight at sea level (pressure altitude), dry runway, and flaps 25, the 747-400 requires just under 7500' runway. At flaps 30 (full flaps), it needs about 6800'.

And you're generally not going to be landing at MLW anyway.
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CosmicCruiser
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RE: Full Flap Landings

Sun May 24, 2009 9:04 am

First are you sure you could tell flaps 35 from flaps 50 (MD-11)? Second for us flaps 50 is more stress on the flaps and airframe and only reduces ldg roll by about 500'. You don't use 50 flaps in high or gusty winds and Vapp isn't much lower. For CATIII you have slightly better angle of vision because of lower deck angle and is recommended.
 
PhilSquares
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RE: Full Flap Landings

Sun May 24, 2009 9:19 am



Quoting Vikkyvik (Reply 16):
And you're generally not going to be landing at MLW anyway.

You will if you do any flying in a 744F!
Fly fast, live slow
 
stillageek
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RE: Full Flap Landings

Sun May 24, 2009 4:19 pm



Quoting Phxpilot (Reply 13):

Ok I thought about this after I posted. For every "normal" landing we use flaps 45.
 
474218
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RE: Full Flap Landings

Sun May 24, 2009 4:40 pm



Quoting Chrisjw (Reply 10):
Does anyone know which airplane has the highest flap setting possible?

50 degrees on DC-8 and DC-10 is the most I have seen.
 
josekmlb
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RE: Full Flap Landings

Sun May 24, 2009 8:06 pm



Quoting Mir (Reply 6):
So if you have a nice long runway where you don't need to stop in a hurry, it might make sense to use a lower flap setting.

Here in MLB our main runway is 10,000+ feet and when the land on 9R almost 99% of the time they will roll all the way down to the end since that is where the terminal is to make less taxi time.
 
vikkyvik
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RE: Full Flap Landings

Sun May 24, 2009 9:16 pm



Quoting PhilSquares (Reply 18):
You will if you do any flying in a 744F!

Interesting. What's the reasoning behind that? Just the fact that they pack it to the gills full of cargo?
I'm watching Jeopardy. The category is worst Madonna songs. "This one from 1987 is terrible".
 
PhilSquares
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RE: Full Flap Landings

Sun May 24, 2009 9:57 pm



Quoting Vikkyvik (Reply 22):
Interesting. What's the reasoning behind that? Just the fact that they pack it to the gills full of cargo?

The more cargo they carry, the more revenue that's generated. That's why there are tech stops enroute when the same type aircraft can carry a pax load non-stop. Cargo doesn't care about enroute time.....
Fly fast, live slow
 
ZBBYLW
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RE: Full Flap Landings

Sun May 24, 2009 10:59 pm

Well I know its not a big airplane - but the C305 has flaps 60  Smile, when you take the power off it drops like a rock.
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Viscount724
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RE: Full Flap Landings

Sun May 24, 2009 11:01 pm



Quoting 474218 (Reply 20):
Quoting Chrisjw (Reply 10):
Does anyone know which airplane has the highest flap setting possible?

50 degrees on DC-8 and DC-10 is the most I have seen.

Maximum flap setting on the De Havilland Comet appears to be more than 50 degrees. Not sure what the actual number was.


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PGNCS
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RE: Full Flap Landings

Mon May 25, 2009 2:10 am



Quoting 474218 (Reply 20):
50 degrees on DC-8 and DC-10 is the most I have seen.

DC-9 as well, although the 50 degree stop is almost always blocked off now for noise purposes. MD-80 max is 40; some L-1011's had 42, but we used 33 as the max. B-757/767 max is 30, and 25 or 30 is common; B-737 has up to 40, but 30 is normally used, and when I flew the 732 we were permitted to do 15 if we wanted to.

Likewise some FBW Airbus operators have made flaps 3 (versus Full...3 an index, not a degree measurement) the norm, and and many operators have made varying lesser flap settings the norm for fuel conservation, noise, and flap wear purposes. Obviously the Captain retains the option of using full flaps if the situation dictates (short or contaminated runway, LAHSO, etc.)

Like CosmicCruiser indicated, common practice is to use the highest setting available to maximize cockpit visual field during low visibility approaches.
 
vikkyvik
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RE: Full Flap Landings

Mon May 25, 2009 5:11 am



Quoting PhilSquares (Reply 23):
The more cargo they carry, the more revenue that's generated. That's why there are tech stops enroute when the same type aircraft can carry a pax load non-stop. Cargo doesn't care about enroute time.....

Gotcha. So you're typically flying somewhere on your "max payload" line, as opposed to "max fuel volume"?

Quoting Viscount724 (Reply 25):
Maximum flap setting on the De Havilland Comet appears to be more than 50 degrees. Not sure what the actual number was.

That is amazing.

I've also always found the inboard flaps on the 777 amazing as well:


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airbuster
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RE: Full Flap Landings

Mon May 25, 2009 10:35 am

25 or 42 on the F70 & 100...with or without speedbrake deployed.

MD11 has 50 max, those really are huge barn doors and generate some noticibale buffet too.

rgds

AB
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113312
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RE: Full Flap Landings

Mon May 25, 2009 2:02 pm

All McDonnell-Douglas jets have 50 degrees as the "Full Flap" setting. However, many operators encourage use of Flap 35 for landing as it places less stress on the structures and reduces fuel consumption/noise during the final approach segment.
 
flaps30
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RE: Full Flap Landings

Mon May 25, 2009 2:20 pm



Quoting MPDPilot (Reply 11):
When your landing on a 10000' runway you have plenty of room and no need to stop super quick. Whereas on a shorter runway full flaps are required just to stop on the runway. It just kind of depends.

I always thought that the flap setting on arriving aircraft was mainly used to keep up sufficient lift while on the lower speeds of an approach. I didnt think it had much to do with slowing the aircraft on touchdown. I thought that was what the spoilers were for.
every day is a good day to fly
 
wilco737
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RE: Full Flap Landings

Mon May 25, 2009 2:21 pm



Quoting Flaps30 (Reply 30):
I always thought that the flap setting on arriving aircraft was mainly used to keep up sufficient lift while on the lower speeds of an approach. I didnt think it had much to do with slowing the aircraft on touchdown. I thought that was what the spoilers were for.

The flaps are used to reduce the approach speed and with a lower approach speed the stopping distance on the runway will be shorter as well.
The spoiler kill all the remaining lift so that the airplane remains on the ground and the brakes can be used properly.

wilco737
 
flaps30
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RE: Full Flap Landings

Mon May 25, 2009 3:28 pm



Quoting WILCO737 (Reply 31):
The spoiler kill all the remaining lift so that the airplane remains on the ground and the brakes can be used properly

I find It interesting that when the spoilers are deployed upon landing, they are used to kill the lift. But when the spoilers are deployed during approach, they are used to help slow the aircraft a bit and the lift is not disturbed.
every day is a good day to fly
 
tdscanuck
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RE: Full Flap Landings

Mon May 25, 2009 3:33 pm



Quoting Flaps30 (Reply 32):

I find It interesting that when the spoilers are deployed upon landing, they are used to kill the lift. But when the spoilers are deployed during approach, they are used to help slow the aircraft a bit and the lift is not disturbed.

Different spoilers (on some aircraft), or different settings for the same spoilers (on others), or some combination thereof. You generally don't deploy full ground spoilers in flight.

Deploying flight spoilers in does dump some lift (this is why they come up to augment the ailerons), but you counter that with angle-of-attack.

Tom.
 
wilco737
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RE: Full Flap Landings

Mon May 25, 2009 3:33 pm



Quoting Flaps30 (Reply 32):
But when the spoilers are deployed during approach, they are used to help slow the aircraft a bit and the lift is not disturbed.

There are 2 sorts of spoiles. The Speedbrake in flight and the ground spoiler. You will not deply all the ground spoilers inflight.
The speedbrake affect lift as well. Not as much (as they are no ground spoilers), but there will be less lift as well. You add more drag as well to slow the airplane down or to get a higher rate of descent.

wilco737
 
ThePinnacleKid
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RE: Full Flap Landings

Mon May 25, 2009 3:47 pm



Quoting Flaps30 (Reply 32):

I find It interesting that when the spoilers are deployed upon landing, they are used to kill the lift. But when the spoilers are deployed during approach, they are used to help slow the aircraft a bit and the lift is not disturbed.

Two completely different things actually.... There are two different panels that raise up on the wings of most commercial jets... typically they are referred to as flight spoilers or speed brakes and ground spoilers or ground lift dumpers.... on the aircraft I fly they are "speed brakes" and "ground spoilers"...

The problem comes in to play that most enthusiasts just call them spoilers because on landing the speed brakes also open along with the ground spoilers... the actuation of the two independent types of devices is done by the same handle... but the aircraft has "switches" on the gear that detect in-flight vs. on the ground so which panels get used depends on the weight being on the wheels... no weight on wheels = no ground spoilers.

As you stated, the flight spoilers/speed brakes are used to either A) allow faster descent rates without an increase of airspeed or B) to slow the aircraft down at a faster rate in level flight.... they do however C) work as an integrated unit with the ground spoilers upon landing to destroy lift and aid in the brake effectiveness

Ground Spoilers have 1 function in life... they come open only when on the ground. They are there to destroy the lift being generated by the wing which places the weight of the aircraft firmly down on the mains... this in turn allows for better effectiveness of the brakes.
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Jetlagged
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RE: Full Flap Landings

Mon May 25, 2009 4:50 pm



Quoting Flaps30 (Reply 32):
I find It interesting that when the spoilers are deployed upon landing, they are used to kill the lift. But when the spoilers are deployed during approach, they are used to help slow the aircraft a bit and the lift is not disturbed.

There is no real difference. Spoilers decrease lift and increase drag whether in flight or on ground. (They change pitching moment too as a matter of fact.) The net effect depends on how many spoiler panels are deflected and by how much.

Quoting Tdscanuck (Reply 33):
Different spoilers (on some aircraft), or different settings for the same spoilers (on others), or some combination thereof. You generally don't deploy full ground spoilers in flight.

Deploying flight spoilers in does dump some lift (this is why they come up to augment the ailerons), but you counter that with angle-of-attack.

Tom.

Well put. Note, if you counter the decrease in lift with increased alpha that further increases drag. If you don't, rate of descent is increased. Either might be desirable depending on the situation. If descending, spoilers allow an increased rate of descent without increasing speed. In level flight they decrease airspeed.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
vikkyvik
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RE: Full Flap Landings

Mon May 25, 2009 5:18 pm



Quoting ThePinnacleKid (Reply 35):
Two completely different things actually.... There are two different panels that raise up on the wings of most commercial jets... typically they are referred to as flight spoilers or speed brakes and ground spoilers or ground lift dumpers.... on the aircraft I fly they are "speed brakes" and "ground spoilers"...

This might be a bit misleading - on many aircraft, the flight spoilers use some of the spoiler panels, with less-than-full deflection, while ground spoilers use all of the spoiler panels, at max deflection.
I'm watching Jeopardy. The category is worst Madonna songs. "This one from 1987 is terrible".
 
fghtngsiouxatc
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RE: Full Flap Landings

Mon May 25, 2009 7:12 pm

I always thought that full flaps on the DC9 was pretty amazing, and then realized they aren't even FULL! I wonder what those flaps look like at 50! Here's a picture showing flaps 50 can only be used for emergencies.


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Also, the Hawker series aircraft, instead of spoilers, have the flaps deploy at an almost 90 degree angle. It's pretty cool!


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474218
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RE: Full Flap Landings

Mon May 25, 2009 7:30 pm



Quoting Flaps30 (Reply 32):
I find It interesting that when the spoilers are deployed upon landing, they are used to kill the lift. But when the spoilers are deployed during approach, they are used to help slow the aircraft a bit and the lift is not disturbed.

Any time a spoiler panel is deployed/extended it reduces/spoils the lift. That is why its called a spoiler.

Quoting WILCO737 (Reply 34):
There are 2 sorts of spoiles. The Speedbrake in flight and the ground spoiler. You will not deply all the ground spoilers inflight.

There are at least two other types of spoilers. Roll control spoilers, some aircraft and many sailplanes have no ailerons and use spoilers for roll control. Additionally, many aircraft use spoilers for roll augmentation. Spoilers that deploy with the up aileron when the flaps are extended.
 
BMI727
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RE: Full Flap Landings

Mon May 25, 2009 9:36 pm



Quoting 474218 (Reply 39):
some aircraft and many sailplanes have no ailerons and use spoilers for roll control.

The Mitsubishi MU-2 and later B-52s for example.

Quoting 474218 (Reply 39):
Additionally, many aircraft use spoilers for roll augmentation. Spoilers that deploy with the up aileron when the flaps are extended.

Usually seen at low speeds. Watch them during a crosswind landing; they get quite a workout.

Quoting Vikkyvik (Reply 37):
This might be a bit misleading - on many aircraft, the flight spoilers use some of the spoiler panels,

I recently flew on a 777 and only the outboard panels deployed in the air, or at least they did far more than the inboards.

Quoting Jetlagged (Reply 36):
Note, if you counter the decrease in lift with increased alpha that further increases drag. If you don't, rate of descent is increased. Either might be desirable depending on the situation. If descending, spoilers allow an increased rate of descent without increasing speed. In level flight they decrease airspeed.

So we can either use them to decrease both lift and drag to descend faster without accelerating or we can do the same yet counter the lost lift with an increased angle of attack (adding even more drag) to just slow quickly yet not lose altitude, right?

Quoting Tdscanuck (Reply 33):
Different spoilers (on some aircraft), or different settings for the same spoilers (on others), or some combination thereof.

Watch videos of the BAe 146 landing. They often come in with the speedbrakes deployed on touchdown (for go around safety?) but the spoilers of course do not deploy until the plane is on the ground.
Why do Aerospace Engineering students have to turn things in on time?
 
JoeCanuck
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RE: Full Flap Landings

Mon May 25, 2009 10:05 pm

Roll spoilers can greatly increase roll effectiveness by augmenting the ailerons. They also reduce adverse yaw created by large aileron deflections.

I believe for most airliners, roll spoilers are only active when the flaps are extended.
What the...?
 
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Jetlagged
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RE: Full Flap Landings

Mon May 25, 2009 11:54 pm



Quoting BMI727 (Reply 40):
Watch videos of the BAe 146 landing. They often come in with the speedbrakes deployed on touchdown (for go around safety?) but the spoilers of course do not deploy until the plane is on the ground.

Deploying the speedbrakes means the engines can remain above idle and so are already spooled up in case of go-around. The tail speedbrake is also a very effective means of approach speed control. Unlike most airliners, 146 liftdumpers don't deploy automatically on touchdown, they need pilot input using the speedbrake lever. As well as the six liftdumper panels, there are an additional pair of spoilers for roll control in flight.

The Fokker 100/70 and F.28 have a similar set up, except the liftdumpers can be armed for automatic deployment on touchdown, and there are no roll spoiler (the liftdumper panels are hydraulically locked closed in flight).
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
CosmicCruiser
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RE: Full Flap Landings

Tue May 26, 2009 1:11 am



Quoting Fghtngsiouxatc (Reply 38):
the Hawker series aircraft, instead of spoilers, have the flaps deploy at an almost 90 degree angle. It's pretty cool!

The HS-125 I used to fly had spoilers and the procedure was on ldg to "lift" the spoiler handle pull it full aft and down and this drove the spoilers to grd. position and flaps to something close to 80 deg I can't remember exactly. It was called lift dump. however we had no reverse.

As Wilco737 has explained the MD-11 uses the same panels for air and grd but on the grd you get a couple more panels. They all kill lift but more so on the grd.
 
Viscount724
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RE: Full Flap Landings

Tue May 26, 2009 1:23 am



Quoting ThePinnacleKid (Reply 35):
Ground Spoilers have 1 function in life... they come open only when on the ground. They are there to destroy the lift being generated by the wing which places the weight of the aircraft firmly down on the mains... this in turn allows for better effectiveness of the brakes.

Accidental deployment of the ground spoilers at about 60 ft.on final approach to YYZ caused the loss of an almost brand-new AC DC-8-63 in 1971. All 109 aboard were killed.
http://aviation-safety.net/database/record.php?id=19700705-0

The DC-8 did not have flight spoilers/speedbrakes which is why the DC-8 was certified for inflight use of thrust reversers. I wonder why DC-8 systems were not designed to prevent deployment of the ground spoilers while airborne? That would likely have prevented this accident, although it's basic cause was the crew using their own ad hoc procedures.
 
PGNCS
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RE: Full Flap Landings

Tue May 26, 2009 4:12 am



Quoting JoeCanuck (Reply 41):
Roll spoilers can greatly increase roll effectiveness by augmenting the ailerons. They also reduce adverse yaw created by large aileron deflections.

I believe for most airliners, roll spoilers are only active when the flaps are extended.

That is incorrect for the aircraft I have flown; on the aircraft I have flown roll spoiler augmentation is available full time.

Quoting Fghtngsiouxatc (Reply 38):
I always thought that full flaps on the DC9 was pretty amazing, and then realized they aren't even FULL! I wonder what those flaps look like at 50!

It's very high drag, and buffet is noticeable. It does lower the deck angle on approach, and it does increase power required on final noticeably.

Quoting Vikkyvik (Reply 37):
This might be a bit misleading - on many aircraft, the flight spoilers use some of the spoiler panels, with less-than-full deflection, while ground spoilers use all of the spoiler panels, at max deflection.

That is a very good general statement. Well put.
 
OffshoreAir
Posts: 128
Joined: Tue May 05, 2009 4:56 pm

RE: Full Flap Landings

Tue May 26, 2009 9:56 am



Quoting JoseKMLB (Reply 21):
Here in MLB our main runway is 10,000+ feet and when the land on 9R almost 99% of the time they will roll all the way down to the end since that is where the terminal is to make less taxi time.

I did my flight training there, and when we use to come in on 9R/27L we use to request "long landing" to shorten our taxi time. We would rocket in on the approach then "chop and drop" to the runway, a lot of times chased by a DL MD-88.
OffshoreAir
 
Pihero
Posts: 4196
Joined: Mon Jan 31, 2005 5:11 am

RE: Full Flap Landings

Tue May 26, 2009 1:14 pm



Quoting JoeCanuck (Reply 41):
I believe for most airliners, roll spoilers are only active when the flaps are extended.



Quoting 474218 (Reply 39):
Additionally, many aircraft use spoilers for roll augmentation. Spoilers that deploy with the up aileron when the flaps are extended.

All the Boeings from the 727 onwards and all the Airbuses use some of the spoilers asymmetrically for roll augmentation at all times. Don't remember about the 707. The general philosophies are similar.

Quoting Flaps30 (Reply 32):
I find It interesting that when the spoilers are deployed upon landing, they are used to kill the lift. But when the spoilers are deployed during approach, they are used to help slow the aircraft a bit and the lift is not disturbed.

You'd have to qualify that. The only airliner I know which would approach with extended spoilers is the L-1011 TriStar and the aim is to use the DLC feature.
You could see the spoilers/speedbrake extend some times for s short moment to slow the airplane down. Pilots would generally avoid using spoilers with flaps extended as the disturbed airflow generates some vibrations that passengers do not like. That also means that some of the lift is dumped with the extension of the spoilers (after all, that's their main purpose).
Contrail designer
 
BMI727
Posts: 11094
Joined: Mon Feb 02, 2009 9:29 pm

RE: Full Flap Landings

Tue May 26, 2009 1:25 pm



Quoting Jetlagged (Reply 42):
Deploying the speedbrakes means the engines can remain above idle and so are already spooled up in case of go-around.

That is what I thought but I wasn't sure.

Quoting PGNCS (Reply 45):
That is incorrect for the aircraft I have flown; on the aircraft I have flown roll spoiler augmentation is available full time.

I think that is correct. But usually when the flaps are retract the aircraft is flying fast enough that the roll spoilers are unnecessary. Roll spoilers are usually only needed at slower speeds, when the flaps would be down.
Why do Aerospace Engineering students have to turn things in on time?
 
474218
Posts: 4510
Joined: Mon Oct 10, 2005 12:27 pm

RE: Full Flap Landings

Tue May 26, 2009 1:47 pm



Quoting Pihero (Reply 47):
You'd have to qualify that. The only airliner I know which would approach with extended spoilers is the L-1011 TriStar and the aim is to use the DLC feature.
You could see the spoilers/speedbrake extend some times for s short moment to slow the airplane down. Pilots would generally avoid using spoilers with flaps extended as the disturbed airflow generates some vibrations that passengers do not like. That also means that some of the lift is dumped with the extension of the spoilers (after all, that's their main purpose).

Direct Lift Control (DLC) on the L-1011 positions spoilers 1-4 to a new null point (7 or 9 degrees up depending on the model) whenever the flaps are extended 30 degrees or more and 2 of the 3 engines are less than full power. DLC allows the L-1011 to make corrections in the altitude on approch without pitching the nose up or down. The spoilers either extend or retract from this new null point when ever the aircraft gets above or below the glide slope.

Quoting PGNCS (Reply 45):
That is incorrect for the aircraft I have flown; on the aircraft I have flown roll spoiler augmentation is available full time.

On the L-1011 roll augmentation is only active with the flaps/slats extended. However, all other spoiler modes are also active. So you could have spoilers 1-4 in the DLC mode, bank the aircraft and spoilers 2-6 on the up aileron wing would extend twice the degrees of the aileron and if you pulled the spoiler handle aft spoilers 1-4 would extend fully.

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