RatherBeFlying,
Consider the other side of the story .. what did you do in basic trainers when the approach was way too high ? .. either go round, or orbit, or sideslip .. the last option increasing drag significantly and increasing the flight path angle. Doesn't matter which aircraft, the result is similar.
Conversely, best climb requires zero sideslip.
The people to talk to are in the soaring (and, I guess, the FJ) fraternity where the bit of string sticky taped to the canopy is pretty commonplace.
Does the ball give you any information on slip (other than indirectly) ? .... as it reacts to forces, not whence comes the wind ...
Big birds don't have much climb fat under critical circumstances .. it is a matter of balancing workload against benefit .. and, apart from the difficulty of flying a steady small bank angle, some systems don't like prolonged small bank .. if my recollection is correct, the B727 VG would re-erect to a false horizon in these circumstances ? .. perhaps others can offer pertinent systems comment ?
For most aircraft, the optimum bank angle is somewhere around 2-3 degrees with the performance wings level being somewhat similar to that with 5 degrees bank .. why put all that work into flying 5 degrees if you aren't going to get a useful benefit ? This doesn't suggest that you ignore the bank in a (near) Vmca situation while you are getting the beast back under your control.
maxalt,
I don't know enough about how Messrs Airbus Consortium go about their business to comment... perhaps some kind soul might fund a few endorsement-related research programs so that I can rectify that deficiency in my skillset ?
However, may I put the following thoughts ..
(a) with the level of computerised assistance/control available in a FBW machine, I would be very surprised if the OEM didn't extract every last ounce of performance out of the aircraft when the automatics are driving ...
(b) are you sure that the commanded bank angle is 5 degrees ? .. or might it possibly be a tad less ?
Optimum OEI climb will always require a touch of bank ... rudder input generates a side force .. and hence a small sideslip .. to kill that undesirable sideslip we need a counter bank to generate, in turn, an opposing slip .. in the ideal situation, the two cancel each other and we end up with zero slip conditions.
The concern is with flight workload/performance benefit, generally, and control in the low speed, (near) Vmca, situation. It is useful to keep separate the control and performance considerations in discussion even if, in practice, we roll them into the one procedural sequence.
I suspect that Boeing's suggestion for the I/F situation is to capitalise on the I/F scan's predominant emphasis on the AH (by whatever name known) .. the roll is obvious for aircraft with a significant yaw-roll coupling, especially at lower speeds, and the counter-roll pilot input quite natural and effective .. PROVIDED that the trained response in the failure case is a near-simultaneous rudder input .. it is probably not so important just how the appropriate control inputs are effected .. rather that they are generated quickly, predictably, repeatably, and effectively.
I presume that Boeing's thoughts are based on research into training methods effectiveness.
For what it may be worth, my observations from the back of the box suggest that the technique readily is adopted by students. The result (in terms of minimising undesired flight path perturbations) probably is better, overall, than using rudder as the initial input. I make this observation subject to three thoughts ..
(a) the greybeard, experienced veteran will get the required end result tidily either way
(b) due to yaw-roll coupling, indelicate rudder input (often associated with lesser experience or inadequate recurrent training) often results in very untidy yaw/roll oscillations as the wee beastie wends its way down a rollercoaster ride with the hapless pilot desperately doing his/her best to rein it in ....
Ignition Override's observations are very pertinent ....
(c) often, in the training situation, interim techniques are an effective way for the student to acquire a difficult skill in a reasonable timeframe.