How much flaps?

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15 years 4 months

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Hi there! I'm lucky enough to travel quite regularly between Heathrow and Charles de Gaulle for work (although when you only spend the day there and only see taxis, work and the airport, it's not as glamourous as you may think), 90% of time with BA. So, I'm very used to every single bit of the experience which, apart from delays and fellow passengers, is very similar all the way through. Now last night, when landing at Heathrow on 09L, I noticed that we only used the first stage of flaps (it looked about 10-15 degrees max), instead of the usual full flaps. We were on an airbus A319. The wind was fairly strong, as the wind sock was almost horizontal but about 20-30 degrees max off the runway. Are there any airline rules or best practices when it comes to using flaps, or is it always at the discretion of the pilot? Could it be that the PF had not done one of these landings for some time and wanted to break the routine, or was it all decided, even before take off, in relation to the braking/stopping distance? In the C172 I fly, I would use less/no flaps in very strong gusty wind conditions... or to practice. Thanks for the info. Cheers, Steph PS we were treated to a particular chatty non-cockpit crew, who told us, among other commentaries, that on the left there was a nice view of Windsor castle and, for the passengers on the right, they were lucky to have first class view of the T5 building site :)
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Profile picture for user Bmused55

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Its basically down to a mix of aircraft weight. Different flap settings will be needed for different weights. The heavier the aircraft, the higher the flap settings upon apporach and landing. I'm not going to even go into what weight equals what flap settings as they are different for each aircraft type and I realy don't know any other than the 757s. I would hazard a guess that your A319 was fairly light. The strong wind probably have had a part to play also. A commercial jet doesn't always need to use full flaps to land.
Profile picture for user SHAMROCK321

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Pilots forgetting to use more flaps isnt uncommon but I doubt that was the case here.

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Flaps are one the most important device in bringing down the landing speeds. For instance, at 200 tons (Boeing 777 maximum weight is about 287 tons and maximum landing weight is around 208 tons), the touch down speed is 135 knots using flaps 30. If the pilot lands with flaps 20 (usually during an emergency landing with one engine only), the landing speed is 147 knots. Thus, an increase of 10 degrees flap would reduce the speed by 12 knots. That would cut down the landing roll by quite a good distance The Boeing 777 can land without the reverse thrust but it would have great problems landing without flaps! However, the Manufacturer is so confident on the reliability of the flaps operation that they have not provided any performance speeds for zero flaps landings other than for 20, 25 and 30 degrees.
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Pilots forgetting to use more flaps isnt uncommon but I doubt that was the case here.
I would disagree with that.
Profile picture for user Bmused55

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Pilots forgetting to use more flaps isnt uncommon but I doubt that was the case here.
is that so? I guess that explains why we hear of planes dropping from the skies while on approach on a regular basis then? :rolleyes:
Profile picture for user SHAMROCK321

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Ive seen a number of prgrammes where pilots forget to deploy more flaps. One case study was Air France who insist that pilots report to a specific person to report any such incidents. Im not sure if other airlines have this system. The case was 2 737 pilots reporting to the guy who was in charge of incidents relating to 737 incidents. They were on approach to Tegal,they landed and reliased that the required flaps hadnt been used.
Profile picture for user David2386

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Is 'forgetting' the correct way? Surely landing flaps is part of the landing checklist, not something you easily forget about. Most tend to handle better in gusting winds with less flaps. I believe there is a situation on the 767 where in particular conditions, VREF for flap 30 is higher than VREF for flap 20. A light A319 with a stiff headwind going into Heathrow could be significantly slower on final approach than the 777 behind it. Runway length is more than sufficient and by using full flap and the slower approach speed, your only wasting time? Perhaps Skycruiser, moondance or wys can explain correctly, but I doubt 'pilots forgetting to use more flaps' is common. Deciding to use less flaps yes, but forgetting?
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Not forget. A constanat strong headwind would require less flap due to the lower landing speed. dme
Profile picture for user Whiskey Delta

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Not forget. A constanat strong headwind would require less flap due to the lower landing speed. dme
Not true. A strong headwind will lower the ground speed but the aircraft still has the same Indicated Airspeed and will use the flaps appropriate regardless. Some aircraft can use reduced flaps in gusting conditions no matter the headwind/crosswind component.
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Oh ok. I know we reduce flap and increase speed in gusting conditions with the C172, but true I still use the same flap setting regardless. dme
Profile picture for user Skymonster

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I know we reduce flap and increase speed in gusting conditions with the C172, but true I still use the same flap setting regardless.
Huh??? :confused: Andy
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In an Airbus (FBW) you preselect the required landing flap in the MCDU. The aircraft completes its own landing checklist and would tell you if the flaps were not in the preselected position when passing 2000'. There are 2 choices of landing setting. Flaps 3 or Flaps Full. We DO NOT make the choice of which one we are going to use based on the aircraft weight but due to wind strength and gust at the arrival airfield. Basically we always use Flaps Full as it reduces our speed at touchdown unless the winds are strong or unpredictable where we use Flaps 3 as it reduces the chance of a tailstrike on landing in these conditions. The only exception to the above would be an equipment malfunction such as flaps or slats jammed in an intermediate position. Forgetting to set landing flap is not really likely in commercial aircraft as you would receive a configuration warning from the GPWS requiring either flap deployment or a go around). My money is on the fact that they did a Flaps 3 landing in this case as the conditions were gusting however the speed reductions were all probably large and consecutive causing in effect the flaps/slats to make one consecutive movement from Flaps Zero to Flaps 3. If I'm wrong then the answer will probably be fully discussed on the R&N front page on prune!
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Also...on an Airbus a particular flap setting might actually give you a different flap/slat setting when retracting as opposed to extending. For example, after a take off with Flap 2, when you retract to Flap 1 you will get both flap and slat whereas when dirtying up to land and you go from Flap Zero to Flap 1 you get flap without slat although you get more angle of flap than before, even though the lever is in the same position. Consequently on the Airbus we refer to configuration settings rather than flap settings. Boeing tend to give you loads of flap positions some of which you skip on the way out and some you skip on the way in. Airbus logic says that the pilot doesn't need to know the angles (hence why we call them Zero, 1, 2, 3 and Full) you just need them to go in or out to whatever the next relevant stage is. It makes life much simpler and reduces the chance of missetting the lever.

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Narrow Body Airbus Flap Values
Just to add what Wysiwyg has said; the Airbus A319's flaps move to different angles than the larger Airbus A320.
Not correct, 319 and 320 are the same, 321 is different. Don't know about the 318, haven't flown it. exmpa
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not that I am questioning you, but what is the source of your info?

Member for

14 years 4 months

Posts: 320

not that I am questioning you, but what is the source of your info?
A319 FCOM 3.1.20/6 Seq 080 A320 FCOM 3.1.20/6 Seq 040 A321 FCOM 3.1.20/6 Seq 085 exmpa
Profile picture for user Bmused55

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A319 FCOM 3.1.20/6 Seq 080 A320 FCOM 3.1.20/6 Seq 040 A321 FCOM 3.1.20/6 Seq 085 exmpa
fair dos ;) Welcome to the forums btw :)