Airbus - Flap FULL or Flap 3??
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The airline I used to work for had 2 A321's based at a UK airport.
They brought in a new procedure one summer which required config 3 when the x-wind component was over a certain limit.
Unfortunately the runway is relatively short (no location mentioned
), and there were approx 5-10 diverts throughout the summer when the procedure was followed.........as the extra landing speed pushed them outside of the braking/stopping performa!
No other airlines had any issue getting in.
The procedure was 'reviewed' come the winter!!!
They brought in a new procedure one summer which required config 3 when the x-wind component was over a certain limit.
Unfortunately the runway is relatively short (no location mentioned
), and there were approx 5-10 diverts throughout the summer when the procedure was followed.........as the extra landing speed pushed them outside of the braking/stopping performa!No other airlines had any issue getting in.
The procedure was 'reviewed' come the winter!!!
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Interesting thread. Just like to make an input re F3 in gusty conditions...
I believe that the primary reason Airbus specifies a F3 landing in gusty conditions is a Flight Control Law issue. As I understand it there is indeed a change to control laws to permit a faster roll rate when operating flap 3. As one responder said earlier on it gives a 'crisper' feel to the a/c.
Many moons ago (early '90s) there was an OEB issued which covered this topic. At that time Airbus did not promote knowledge of OEBs and many crews were ignorant of them. During a very gusty approach, one of our crews experienced a slat jam. Due to a poor ECAM directive (since changed) they ended up selecting the wrong flap setting and the result was an a/c that was extremely sensitive to roll input. The resulting landing was very exciting indeed!
Airbus later explained that by setting the flap handle to a position other than close to the actual flap/slat setting, the a/c control laws were mismatched witht the aerodynamics and the a/c became ultra sensitive to roll input. From memory this was not a Normal vs Alternate law issue but occurs in Normal law all the time.
F3 gives greater roll control and a faster roll response which is why there may be a case for using it in large crosswinds as it will result in more capability as one decrabs in the flare. Was the lack of roll response not an issue with the (relatively) recent LH wingtip strike?
I believe that the primary reason Airbus specifies a F3 landing in gusty conditions is a Flight Control Law issue. As I understand it there is indeed a change to control laws to permit a faster roll rate when operating flap 3. As one responder said earlier on it gives a 'crisper' feel to the a/c.
Many moons ago (early '90s) there was an OEB issued which covered this topic. At that time Airbus did not promote knowledge of OEBs and many crews were ignorant of them. During a very gusty approach, one of our crews experienced a slat jam. Due to a poor ECAM directive (since changed) they ended up selecting the wrong flap setting and the result was an a/c that was extremely sensitive to roll input. The resulting landing was very exciting indeed!
Airbus later explained that by setting the flap handle to a position other than close to the actual flap/slat setting, the a/c control laws were mismatched witht the aerodynamics and the a/c became ultra sensitive to roll input. From memory this was not a Normal vs Alternate law issue but occurs in Normal law all the time.
F3 gives greater roll control and a faster roll response which is why there may be a case for using it in large crosswinds as it will result in more capability as one decrabs in the flare. Was the lack of roll response not an issue with the (relatively) recent LH wingtip strike?
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Hello,
Airbus does not specify any flap 3 landing in gusty conditions. It specifies the use of flap 3 as a recomendation in cases of windshear/downburst phenomena to keep a higher energy level during the approach. GS mini function is designed to cope with gusty winds regardless of flap selection. The flight control law remains the same regardless of flap selection either.
Don't know about early 90's, but from mid 90's Airbus has promoted lots of knowledge of OBs and OEBs. The ECAM directives in case of a slat/flap fault (jam) are not a big issue. The main part of it comes with the paper checklist.
Flap 3 will give you also a reduced tailstrike margin (up to the A320), to be considered when landing in gusty crosswind conditions.
I believe that the primary reason Airbus specifies a F3 landing in gusty conditions is a Flight Control Law issue. As I understand it there is indeed a change to control laws to permit a faster roll rate when operating flap 3. As one responder said earlier on it gives a 'crisper' feel to the a/c.
Many moons ago (early '90s) there was an OEB issued which covered this topic. At that time Airbus did not promote knowledge of OEBs and many crews were ignorant of them. During a very gusty approach, one of our crews experienced a slat jam. Due to a poor ECAM directive (since changed) they ended up selecting the wrong flap setting and the result was an a/c that was extremely sensitive to roll input. The resulting landing was very exciting indeed!Airbus later explained that by setting the flap handle to a position other than close to the actual flap/slat setting, the a/c control laws were mismatched witht the aerodynamics and the a/c became ultra sensitive to roll input. From memory this was not a Normal vs Alternate law issue but occurs in Normal law all the time.
F3 gives greater roll control and a faster roll response which is why there may be a case for using it in large crosswinds as it will result in more capability as one decrabs in the flare. Was the lack of roll response not an issue with the (relatively) recent LH wingtip strike?
F3 gives greater roll control and a faster roll response which is why there may be a case for using it in large crosswinds as it will result in more capability as one decrabs in the flare. Was the lack of roll response not an issue with the (relatively) recent LH wingtip strike?
Flap 3 will give you also a reduced tailstrike margin (up to the A320), to be considered when landing in gusty crosswind conditions.
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Flap 3 will be preferred config as environmental aspects come more into the play. Emission charges will drive the industry towards low drag low noise approach techniques along with CDO. Nothing wrong with F3 as it gives lots of advantages as mentioned before probably most significant one being improved go around performance along with higher energy during approach. One can argue about better controllability through higher approach speed and easier handling of de-crab. Unless circumstances dictate otherwise I don't see any reason not to use F3. Such circumstances might be tailwind, LDA, RWY status etc. F3 is a good overall compromise 
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I don't get it; the computers are flying the airplane (FBW) so what difference does it make? From what I have been told you simply set the profile and the computer maintains it, no need to make any corrections due to flap setting, gusts etc. Trying to compensate causes over -control? I am not knocking Airbus, just a little confused.
Also, a difference in approach speed of 5 knots is not significant unless the runway was less than 1600 metres, surely? For the vast majority of approaches either flap could be used, or else you would not be able to land there with an engine out.
Also, a difference in approach speed of 5 knots is not significant unless the runway was less than 1600 metres, surely? For the vast majority of approaches either flap could be used, or else you would not be able to land there with an engine out.
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IDG
You are right except for the Control Law Change, you remain in Normal Law however the roll rate versus the side stick deflection is different because of the following:
A 5 degree per second sidestick command in in CONF FULL results in Aileron and Spoiler deflections of approximately 11.5 degrees and 3 degrees respectively.
The same sidestick command in CONF 3 results in 18 degrees and 8 degrees respectively.
Therefore the aircraft is more sensitive in CONF 3 than CONF FULL. This is the reason that some companies including the one I work for recommend the use of F3 in windshear or indeed very gusty conditions. The 'crispness' of control as somebody mentioned is for this reason.
Merry Christmas all......I can't believe I'm on here tonight....time to get off.
Finally, one of our training requirements is ensure that the pilots are aware of the of the possibility of PIO in this configuration, since we use CONF FULL still as our 'normal' Landing Configuration and the 'feel' and response is slightly different.
A 5 degree per second sidestick command in in CONF FULL results in Aileron and Spoiler deflections of approximately 11.5 degrees and 3 degrees respectively.
The same sidestick command in CONF 3 results in 18 degrees and 8 degrees respectively.
Therefore the aircraft is more sensitive in CONF 3 than CONF FULL. This is the reason that some companies including the one I work for recommend the use of F3 in windshear or indeed very gusty conditions. The 'crispness' of control as somebody mentioned is for this reason.
Merry Christmas all......I can't believe I'm on here tonight....time to get off.
Finally, one of our training requirements is ensure that the pilots are aware of the of the possibility of PIO in this configuration, since we use CONF FULL still as our 'normal' Landing Configuration and the 'feel' and response is slightly different.
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IGh, your approach is way to high and theoretical if I may say so. It really all boils down to the approach strategy planning and that includes energy management, speed controls, stabilisation criterion, landing technique, go around strategy last but not least noise, emission etc. As a commander of a modern airliner one clearly has priorities, safety being indisputably number 1 whereas economical aspects should find considerations as well. Having said all that, approaching busy hubs nowadays like LHR etc, F3 landing gives significant advantages in all aspects including better achievements of stabilisation due to higher Vapp. Bear in mind that most of the major airports require to keep min 160 till 4 NM. Well there's a higher pitch and tail strike is more probable etc but let me ask you how do you intent to land A330 single engine mate? In the end if one doesn't feel comfortable with F3 landing no big deal, go for full.
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the famous "what if" and reasonable assumption along with the probability theory is a never ending story in aviation dear IGH. Usually 320 drivers are the once objecting F3 Landing even though it's the easiest airbus to land with F3. Wide body airbus drivers regularly perform F3 approaches and landings simply coz they have the option of flap selection in the FMGEC. Bottom line is if a pilot must land a 330 F3 SE than surely he/she is capable of doing it in normal config. Once again if not comfortable don't do it but it's a personal choice not the scientific conclusion. The only time when I prefer to go full flaps is when I'm shooting CAT I up to CAT III with DH due the requirement of a visual segment at DA/DH. In this case each degree of lower pitch increases my chances to acquire visual cues hence Full Flap
