Side Slip (wing down/cross control) Landing Technique on Airbus (A330)
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That's a 'good' one!!!Another thing which I was told; Airbus does not build its landing gears to withstand the lateral loads of landing without decrabbing. Such a 'technique' usually results in significant damage.
Just to share.
vilas; i am going through hell-day contingencies being new to the bus. One of the scenario given is all eng flameout. Am thinking what to do when you are on finals and high, not high enough for an orbit but high enough to have the speed being excessive. Better be prepared with my plans and options rather than thinking about it when the sxxx hits the fan.
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TyroPicard,
Thanks for your reply. As you said because there is no input in the side stick there should be no bank. There is pitch and lateral law but there isn't any yaw law as I thought it is to supplement the roll (lateral). I think the yaw is used by the computer to coordinate the turn. Hence when there is no turn the computer will neutralize the rudder. But when the pilot makes a rudder input, will the computer try to counter this with the primary objective as 0 roll rate?
I am not trying to split hairs or be an engineer but I really hope to know and understand what the aircraft does especially maneuvers which is close to ground where I don't have much room to play or experiment with.
Thanks for your reply. As you said because there is no input in the side stick there should be no bank. There is pitch and lateral law but there isn't any yaw law as I thought it is to supplement the roll (lateral). I think the yaw is used by the computer to coordinate the turn. Hence when there is no turn the computer will neutralize the rudder. But when the pilot makes a rudder input, will the computer try to counter this with the primary objective as 0 roll rate?
I am not trying to split hairs or be an engineer but I really hope to know and understand what the aircraft does especially maneuvers which is close to ground where I don't have much room to play or experiment with.
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titaniumwings
If you are new to the Bus then FCOM and FCTM should be your bible. If you didn't understand something from that you can ask some one to explain in PPRUNE. Do not learn flying here. Lot of things some incorrect and some downright dangerous are suggested in these columns. The most dangerous thing to do is start making your own procedures in Airbus FBW. Airbus is flown only one way and that is airbus way. There is no place for experimentation listening to some one no matter how experienced he is. Do not compare it with previous aircraft. One very senior airbus industry instructor told me if you have taken a new girl friend do not compare her with your old one the result will not be pleasant. Also I can feel you are reading procedures as if they are horror stories. In air if you misjudged something there is limit only within which you can recover. If everything was recoverable there would be no accidents. You don't side slip big aircraft and first try to fully understand laws in normal flying and not aerobatics.
If you are new to the Bus then FCOM and FCTM should be your bible. If you didn't understand something from that you can ask some one to explain in PPRUNE. Do not learn flying here. Lot of things some incorrect and some downright dangerous are suggested in these columns. The most dangerous thing to do is start making your own procedures in Airbus FBW. Airbus is flown only one way and that is airbus way. There is no place for experimentation listening to some one no matter how experienced he is. Do not compare it with previous aircraft. One very senior airbus industry instructor told me if you have taken a new girl friend do not compare her with your old one the result will not be pleasant. Also I can feel you are reading procedures as if they are horror stories. In air if you misjudged something there is limit only within which you can recover. If everything was recoverable there would be no accidents. You don't side slip big aircraft and first try to fully understand laws in normal flying and not aerobatics.
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Once again I thank you those who give me advice and recommendations especially on techniques.
I have developed an approach to my operations (but always learning and in the process of refinement). As a pilot it is important to know the books. Attention to limitations are essential. Those are usually non-negotiable. When reading the books attention to the wording is important. Most of them are written with much thoughts. 'Must' and 'should' are used appropriately.
Beyond knowing the books understanding the underlying reasons helps to mature one's operations. This is especially true for recommended techniques. There are many instances of instructors debating over different techniques but the management usually takes the macro view of pilots exercising their judgement and determining what is the best course of actions. This is to the exception where certain techniques which may be prohibited due certain restrictions. These limitations must be adhered to.
I listen to the range of views and opinions especially those with accompanying reasons. This develops my understanding and judgement in determining the best course of action. I will comb the books and web for answers and when not satisfactory I may consult as much resources as I could. After getting the range of opinions I have to evaluate critically and determine the best course of actions.
Nonetheless I appreciate any effort to share. Again, much appreciation for the spirit of sharing guys.
Also I will decrab for landing 
Ps: Airbus told me that this aircraft can be flown like any other aircraft. But I feel that it is essential to know their FBW laws and characteristics. I also read their FCB: Yaw Disturbances During Takeoff Roll which pay special attention to the improper use of rudder. An accident that I have visited was AA 587 which was a B737 nonetheless. I try to learn from all the incidents and accidents, don't think I live long enough to make all the mistakes especially the ones I learned.
I have developed an approach to my operations (but always learning and in the process of refinement). As a pilot it is important to know the books. Attention to limitations are essential. Those are usually non-negotiable. When reading the books attention to the wording is important. Most of them are written with much thoughts. 'Must' and 'should' are used appropriately.
Beyond knowing the books understanding the underlying reasons helps to mature one's operations. This is especially true for recommended techniques. There are many instances of instructors debating over different techniques but the management usually takes the macro view of pilots exercising their judgement and determining what is the best course of actions. This is to the exception where certain techniques which may be prohibited due certain restrictions. These limitations must be adhered to.
I listen to the range of views and opinions especially those with accompanying reasons. This develops my understanding and judgement in determining the best course of action. I will comb the books and web for answers and when not satisfactory I may consult as much resources as I could. After getting the range of opinions I have to evaluate critically and determine the best course of actions.
Nonetheless I appreciate any effort to share. Again, much appreciation for the spirit of sharing guys.
Also I will decrab for landing Ps: Airbus told me that this aircraft can be flown like any other aircraft. But I feel that it is essential to know their FBW laws and characteristics. I also read their FCB: Yaw Disturbances During Takeoff Roll which pay special attention to the improper use of rudder. An accident that I have visited was AA 587 which was a B737 nonetheless. I try to learn from all the incidents and accidents, don't think I live long enough to make all the mistakes especially the ones I learned.
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Can't say for the big twin, but for the 737 the sideslip (wing low) method is actually one of the boeing approved methods, up to a crosswind component of 17 kts at flaps 15, 20 kts at flaps 30 and 23kts at flaps 40.
Two other techniques are described, one being touchdown in full crab, which is approved up to the 40kts crosswind limit, but not recommended on dry runways, however is recommended on wet or slippery runways. The other one is the overall recommended technique of de-crab during flare.
The fail operational autoland uses a mix of wing low (up to 7° of bank if memory serves right) and crab.
Two other techniques are described, one being touchdown in full crab, which is approved up to the 40kts crosswind limit, but not recommended on dry runways, however is recommended on wet or slippery runways. The other one is the overall recommended technique of de-crab during flare.
The fail operational autoland uses a mix of wing low (up to 7° of bank if memory serves right) and crab.
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decrab in flare on both 737 and a320. Have never seen a 737 come down with wing-low method on approach. If you do this you are a minority.
As for all engine out method, just stick the nose down and pitch for the runway threshold at FULL flap. You won't be at optimal glidespeed so you loose altitude faster.
Unless you picked the shortest runway in town the wheelbrakes will stop you, just don't try to achieve a smooth touchdown.
As for all engine out method, just stick the nose down and pitch for the runway threshold at FULL flap. You won't be at optimal glidespeed so you loose altitude faster.
Unless you picked the shortest runway in town the wheelbrakes will stop you, just don't try to achieve a smooth touchdown.
Usual hysteria about 'sideslip in airliners'
If it is that dangerous then why is it built in to every autoland system on modern Boeing aircraft ?
Try watching the different stages of autoland to see this wing down correction introduced by the autopilot, very smoothly while limiting the bank angle at touchdown.
In manual flight it nearly always produces a better, more predictable result than the 'push it straight at the last second' technique.
If it is that dangerous then why is it built in to every autoland system on modern Boeing aircraft ?
Try watching the different stages of autoland to see this wing down correction introduced by the autopilot, very smoothly while limiting the bank angle at touchdown.
In manual flight it nearly always produces a better, more predictable result than the 'push it straight at the last second' technique.
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stilton
By slide slip I do not mean wing down approach. titaniumwings wants to slide slip to loose height. I would like to know which commercial aircraft manufacturer recommends this.
By slide slip I do not mean wing down approach. titaniumwings wants to slide slip to loose height. I would like to know which commercial aircraft manufacturer recommends this.
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Thanks for sharing the different techniques on different types guys.
Denti, B777 seems to share similar techniques to the B737. The gears can take the no de-crab. But most pilots would.
I was asking for recommendations. Thanks to 737Jock for his recommendation
vilas;
I would like to reiterate my position: I am trying to investigate and reaffirm my knowledge of Airbus FBW laws and characteristics. In the process I also thought about contingency plans for all eng out forced landing piloting techniques especially to losing height at finals in case of being caught high and fast. I am not about to give up in that situation and have learned of a few techniques which did include side slip to lose height in my early days. I have not seen an outright limitation on this nor am I recommending it. Neither could I find a recommended technique for this situation in FCTM. I am open to suggestions and would be enlightened if I could be pointed to the reason(s) as to why not for this technique, be it references or even technical explanation. I have in mind more than 1 technique and had evaluated the plus and minus of each but I always like to learn from others if they are kind enough to offer.
Thanks in advance to those who do. Cheers guys.
Denti, B777 seems to share similar techniques to the B737. The gears can take the no de-crab. But most pilots would.
I was asking for recommendations. Thanks to 737Jock for his recommendation
vilas;
I would like to reiterate my position: I am trying to investigate and reaffirm my knowledge of Airbus FBW laws and characteristics. In the process I also thought about contingency plans for all eng out forced landing piloting techniques especially to losing height at finals in case of being caught high and fast. I am not about to give up in that situation and have learned of a few techniques which did include side slip to lose height in my early days. I have not seen an outright limitation on this nor am I recommending it. Neither could I find a recommended technique for this situation in FCTM. I am open to suggestions and would be enlightened if I could be pointed to the reason(s) as to why not for this technique, be it references or even technical explanation. I have in mind more than 1 technique and had evaluated the plus and minus of each but I always like to learn from others if they are kind enough to offer.
Thanks in advance to those who do. Cheers guys.
Last edited by titaniumwings; 9th Nov 2014 at 10:51.
Vilas----gidday again mate, in the flare during a strong crosswind you will need to apply ( with a crosswind for the right ) LEFT rudder and then RIGHT Aileron into wind and probably have to hold those inputs in to control the Aircraft smoothly onto the ground on the upwind wheels.
So isn't that a small sideslip?
Unless you are very quick and push the rudder quickly to align the nose just before touchdown and don't need any wing down you MUST have to apply opposite control input at the same time....
Sideslip.....
Anyway mate it works for me.
I assume that's what you do as well?
So isn't that a small sideslip?
Unless you are very quick and push the rudder quickly to align the nose just before touchdown and don't need any wing down you MUST have to apply opposite control input at the same time....
Sideslip.....
Anyway mate it works for me.
I assume that's what you do as well?
Last edited by ACMS; 9th Nov 2014 at 11:50.
Titaniumwings-------Also remember the Transat A330 dead stick approach after running out of fuel over the Atlantic, the machine glides so well they needed to use a lot of side slipping after getting too high on their approach. Worked well for them on the day and they managed to land and stop with blown wheels.....ok:
Not that I would sideslip in any other situation in a commercial Jet but in an Emergency like they had all bets are off!! You do what you need to..
Not that I would sideslip in any other situation in a commercial Jet but in an Emergency like they had all bets are off!! You do what you need to..
Last edited by ACMS; 9th Nov 2014 at 11:53.
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ACM
You hold the crab till flare. After flare you straighten the nose with rudder or hold 5 degrees crab if too strong a wind and use stick as required to maintain direction or the centre line in that you may use 5 degrees of bank before touch down. That is the recommended technique for all not only for you. The dispute is can you do it from 100ft or 200ft? Airbus does not recommend it and the reason is stick out of neutral is rate of roll demand. If you want to do it ask the airbus. Don't develop procedures on your own or drag Boeing procedures in AB FBW.
You hold the crab till flare. After flare you straighten the nose with rudder or hold 5 degrees crab if too strong a wind and use stick as required to maintain direction or the centre line in that you may use 5 degrees of bank before touch down. That is the recommended technique for all not only for you. The dispute is can you do it from 100ft or 200ft? Airbus does not recommend it and the reason is stick out of neutral is rate of roll demand. If you want to do it ask the airbus. Don't develop procedures on your own or drag Boeing procedures in AB FBW.
Last edited by vilas; 9th Nov 2014 at 12:07. Reason: correction
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OK, I'll review it for myself.
When talking about if you are able to land the Airbus FBW (I only know 320 family) in crosswind using the "wing down/cross control side slip method", I'd like to make different considerations.
- Airbus clearly recommends the crab technique. Why? They didn't tell us! But it is a recommendation. They didn't say it's a must or any other technique is prohibited or any other technique is not possible or discouraged because the flight controls. In the other hand if the manufacturer is recommending you something....better to follow it! But still a recommendation.
- There is nothing in the flight controls system that prevents you to do so. You make a roll input in the sidestick to produce a roll rate until you have the target bank and then go to neutral to order roll rate zero and the desired bank will be maintain (it doesn't matter if the target bank is zero or 5 or any other until 33 or if you are changing your heading or keeping it). Of course in real life you have to work on it the same way you have to do it in every landing, with the only difference that the target bank won't be zero. Simultaneously you use the rudder to align the aircraft with the runway centerline. You will flight straight and the computers will be happy because they are doing what they are supposed to do and nothing else. Just the same way you'd fly any other aircraft.
- Is it difficult? I don't think so, but as any other technique, has to be trained, and the more you do it the easier it become. Will you train it? I don't think so because it is not the recommended technique.
- ACMS and hikoushi: wise words, thank you!
- Titaniumwings: don't worry! You won't crash so easily! Just an aircraft! Enjoy it!
When talking about if you are able to land the Airbus FBW (I only know 320 family) in crosswind using the "wing down/cross control side slip method", I'd like to make different considerations.
- Airbus clearly recommends the crab technique. Why? They didn't tell us! But it is a recommendation. They didn't say it's a must or any other technique is prohibited or any other technique is not possible or discouraged because the flight controls. In the other hand if the manufacturer is recommending you something....better to follow it! But still a recommendation.
- There is nothing in the flight controls system that prevents you to do so. You make a roll input in the sidestick to produce a roll rate until you have the target bank and then go to neutral to order roll rate zero and the desired bank will be maintain (it doesn't matter if the target bank is zero or 5 or any other until 33 or if you are changing your heading or keeping it). Of course in real life you have to work on it the same way you have to do it in every landing, with the only difference that the target bank won't be zero. Simultaneously you use the rudder to align the aircraft with the runway centerline. You will flight straight and the computers will be happy because they are doing what they are supposed to do and nothing else. Just the same way you'd fly any other aircraft.
- Is it difficult? I don't think so, but as any other technique, has to be trained, and the more you do it the easier it become. Will you train it? I don't think so because it is not the recommended technique.
- ACMS and hikoushi: wise words, thank you!
- Titaniumwings: don't worry! You won't crash so easily! Just an aircraft! Enjoy it!
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ACMS: How can anyone forget Air Transat 236, an Airbus 330. You put it in perspective.
Gryphon: I have considered your approach, interpretation and technique analysis. Totally agree with you philosophy and perspective.
Wise words by wise aviators!! Thanks for the learning and sharing session.
Gryphon: I have considered your approach, interpretation and technique analysis. Totally agree with you philosophy and perspective.
Wise words by wise aviators!! Thanks for the learning and sharing session.
Vilas-----mate mate mate
Please re read my post particularly the underlined bold part where I stated with emphasis I was speaking of during the flare manoeuvre. No where did I say to start the side slip earlier, a technique I have seen on conventional aircraft but not on Airbus FBW. I don't use that technique myself either.
Eaelier I posted the A330 FCTM reference to crosswind technique which I do follow quite well even in gusty typhoons as per Airbus and company policy/training, so I'm not using my old 777 737 747 experience. ( although they are indeed the same )
Cheers
Please re read my post particularly the underlined bold part where I stated with emphasis I was speaking of during the flare manoeuvre. No where did I say to start the side slip earlier, a technique I have seen on conventional aircraft but not on Airbus FBW. I don't use that technique myself either.
Eaelier I posted the A330 FCTM reference to crosswind technique which I do follow quite well even in gusty typhoons as per Airbus and company policy/training, so I'm not using my old 777 737 747 experience. ( although they are indeed the same )
Cheers
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Villas,
How much side slip do you think you have with a badly trimmed aircraft during an engine failure on take off? Even with a big side slip, the bank can be held constant with neutral side stick. The tail doesn't fall off either.
At some time or another, most pilots will have flown the Airbus sim with lots of side slip and not realised until spotting the Beta target / slip indicator. You don't need constant aileron to control the slip induced roll. The computers are doing it for you.
What do you think the FBW computers are doing differently when side slipping at 2,000 ft with all engines at symmetrical power and flying with the slip indicator not centred during EFTO?
The dispute is can you do it from 100ft or 200ft? Airbus does not recommend it and the reason is stick out of neutral is rate of roll demand. If you want to do it ask the airbus
At some time or another, most pilots will have flown the Airbus sim with lots of side slip and not realised until spotting the Beta target / slip indicator. You don't need constant aileron to control the slip induced roll. The computers are doing it for you.
What do you think the FBW computers are doing differently when side slipping at 2,000 ft with all engines at symmetrical power and flying with the slip indicator not centred during EFTO?
Last edited by Goldenrivett; 10th Nov 2014 at 11:23. Reason: typo
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It is my well considered opinion that pilot should stick to Airbus recommendations in FBW aircraft. Because line pilot does not have access to the software, hardware or wind tunnel or has the training or opportunity to test fly. Also the manufacturer is in touch with all customers across the globe and is aware of all incidents. Therefore they are in a better position to approve or disapprove certain way of doing things. If you develop your own procedures in isolation there may not be a crash but in different circumstances and situations it may lead to undesirable state. Can you side slip an airliner to lose height like a small trainer? If your answer is yes I have nothing more to say but good luck. Till the A300 crashed in New York they didn't know that overuse of rudder can cause the tail to brake off did they?
It is my well considered opinion that pilot should stick to Airbus recommendations in FBW aircraft. Because line pilot does not have access to the software, hardware or wind tunnel or has the training or opportunity to test fly. Also the manufacturer is in touch with all customers across the globe and is aware of all incidents. Therefore they are in a better position to approve or disapprove certain way of doing things. If you develop your own procedures in isolation there may not be a crash but in different circumstances and situations it may lead to undesirable state. Can you side slip an airliner to lose height like a small trainer? If your answer is yes I have nothing more to say but good luck. Till the A300 crashed in New York they didn't know that overuse of rudder can cause the tail to brake off did they?