I have big ears and always like to listen. Now I am listening to aviators all around the world the comparing the pros n cons of the side slip vs crab-decrab method. The passion of everyone loving their art is really heartening and invigorating. Always love listening to aviator's stories and their craft.
I was taught both when I first started flying. I also read the pros n cons of both. I saw both being practiced in the Boeing and many other aircrafts but just to have a particular discussion on Airbus as its FBW has certain characteristics which make the side slip method quite a topic for discussion.
This is especially so because both the side-slip and crab-decrab method are predicated in Boeing FCTM but Airbus specifically predicate crab-decrab method in their FCTM without any restriction or limitation being mentioned anywhere else. I do not have a problem with Airbus recommendation but for those who ever wish to try the side-slip method on Airbus, an understanding of the aircraft Law would be beneficial to the action-reaction/see n react that thing pilot does. In the real world not thoroughly understanding this part may not result in critical consequences. I just like to know the aircraft intimately. BTW I used the crab-decrab method but I don't judge those who use side-slip. I like to keep things simple and just follow the recommendations whenever I can but when someone asks me I wish to be in a position to tell yes and no with the corresponding reasoning and explanations especially technically.
ps: But if someone has time and free then consider the question that I last posted in #44. I believe there is a group which has the following interpretation:
In a steady state crosswind with Airbus FBW Lateral Law the roll rate is ordered by the side stick. Computer will order rudder output for turn coordination (centering the "ball") and yaw damping. Hence in wings level condition and without sidestick input, 0 roll rate will be ordered.
Now here is the key: Will this order be continued when pilot give a rudder input. In other words will the aircraft's computer order the rest of the control surfaces to give 0 bank as the sidestick still orders "0" roll rate? From what I read, I believe some people believe this and expect the wings to be level when they input the rudder in decrabbing. (The other interpretation will have the pilot putting in a coordinated aileron with the rudder input when decrabbing).
Should this be the case then consider when you are turning the aircraft with 5 degree angle of bank then you neutralise the sidestick. Aircraft will order the rudder accordingly to coordinate the turn. Now you put in rudder input, will the computer still order the rest of the control surfaces for "0" change in roll rate to maintain your 5 degree angle of bank? (some may even take it as "in-between" the 2)
In the real world, wind is not constant and pilot will do whatever is necessary(inputs accordingly) to keep the heading down the runway and aileron correspondingly to keep the aircraft on the centreline.
Nonetheless if the interpretation of the aircraft reaction is valid then there is a bearing on the "way" the aircraft can be "used" to the the sideslip method. This thread is started by the comment that I have heard some people saying that Airbus can't do sideslip method for landing, by that I mean side-slipping the aircraft at 400'. For the purpose of this discussion let's simplify the comparison between crab-decrab (as most may have known it) and sideslip to mean sideslipping starting at short finals of below 400' but above flare height. It is also clear to me that most (if not all) know how to fly their aircraft and do their jobs. I and we are not contra-recommending any change in techniques, just a simple exploration of the aircraft that we love.
Thank you for your time and consideration.
Last edited by titaniumwings; 15th Nov 2014 at 13:26.