RWL;
2. Both CVR transcripts (Taipei and Congonhas), and that Madeira landing video, show the 'Retard' call being heard two or three times before the pilots actually pulled the levers back. Presumably the call is triggered at or around say 20' Radio Altitude? Possibly it's timed a bit early - and sounds rather before the pilot's eye tells him that it's time to flare and retard? No big deal, 'one of those things' on the face of it - but if that's so, it's yet another reason why the 'Retard' call may be treated as a mere 'cue' rather than any sort of warning? Especially since it then cuts out.
This is from the A320 AOM, SOP's chapter:
Predetermined altitude call outs are computer generated by the Flight Warning Computer (FWC)
below 400 ft RA. Auto call out by the FWC below minimums/decision include "100", "50", "30" then
"RETARD", "RETARD" is generated if the Thrust Levers are not at idle by 20 ft (manually flying) or
by 10 ft (autoflight engaged).
AT 30 FT APPROX
Commence a gentle progressive flare and allow the aircraft to touch down without prolonged float
simultaneously moving the Thrust Levers to idle.
I have always understood and treated the "retard" call as a cue, not a "warning". In my Airbus course, we were always taught that one should not hear the "retard" call from the FWC's because the thrust levers should already be closed to the IDLE position. In practice, one, two and on rare occasions three calls may be heard if one delays the reduction to achieve a smooth landing but that is not what Airbus wants.
And a question for A320 pilots. From the Madeira video, and what I know of the manual, and Eric Parkes' notes, I gather that when coming OUT of reverse you have to make sure that you push the levers right through the 'idle detent,' and then pull them back again, to ensure positive location IN the detent as opposed to just 'nearly' in it.
Although it is not needed/indicated/required by the AOM or AI, there is the tendency among crews to do this. The material effect is minimal in the sense that there is little if any increase in engine thrust as a result of such a quick maneuver. I suppose the tendency may come from just what you say - to "ensure' that everybody is in forward thrust again.
Is it the same when retarding to idle in the flare - that is, you have to pull the levers firmly back, against the resistance of the 'detent' mechanism, to make sure that they are firmly seated? How much 'feel' do you actually get? Is it, for example, the same sort of 'feel' you get when pulling a car's gearshift back through reverse and neutral into 'drive'?
There is no need to ensure that the thrust levers are "firmly seated" when pulling them back. There is no "detent", but only a mechanical stop.
The A320 thrust levers are, despite the wide-ranging controversies and opinions, ordinary thrust levers with ordinary, pilot-expected responses. They are as benign a cockpit control as, say, the flap lever. Of this view, more in a moment...
Re "feel", there is no "reverse detent" so there is no sense that one is in "neutral" as in the metaphor you use, (car gearshift neutral position). It is merely a stop, beyond which the levers cannot move until the reverse "paddles" mounted on the front of the TL's are raised.
Unlike the A330/A340 thrust levers which have more conventional thrust reverse levers attached to the thrust levers and brought up and back in traditional manner, the A320-type reverse levers are small "paddles" which when pulled upwards release the interlocks so that the thrust levers may travel further aft into the "Reverse thrust" regime.
Re "feel" again, the thrust levers I have used on the 320 fleet type can vary in "resistance" in movement. Some I have used are tight and require a solid pull/push to move and others are quite "loose" and move fore-and-aft more than easily.
On landing, both levers are pulled smartly aft against the mechanical stop, which is then released by raising the paddles described above. The TL's then are free to move into the aft (reverse) regime. If a reverser is locked out (MEL'd), no effect other than a slight increase in N1 speed results. I believe (there is no information in the AOM on this) that no cockpit indications occur except that "REV" does not appear in green in the N1 guage on the ECAM but I stand to be corrected on this recollection.
Technically ONLY (in other words, this is to increase understanding of the system and is NOT to be taken as a technique or a recommendation. Such use is strictly against AI SOPs and is warned against!), the thrust levers could be pulled into the regime anytime before touchdown during the flare if the reverse paddles are pulled up. The system is designed such that nothing would happen until the aircraft-on-ground regime was established. This is possible because the FADECS will control the reverser and thrust sequencing. This is not the case with the A330/340 reverse thrust levers which are truly locked out, (cannot be raised up and back) until ground-regime is established by the relevant aircraft systems.
Regarding the "benign controls" comment above I would like to posit an impression that occurred to me when I first began flying the 320 in early 1992 and which hasn't left me. Almost certainly others have felt the same thing and I know it has been expressed in some form within this thread.
I wonder if there is something beyond "normal" human factors at work here which uniquely involves the A320 fleet-type. Perhaps we might call it "the illusion of complexity". I quickly add that I don't mean to dismiss the airplane's complexity by any means because it is there. By that term I mean, there exists a mode of thinking regarding the 320 which does not seem to have emerged with any other type - that the airplane is "not an airplane" and it's various systems' responses may, on some rare occasions, have to be "out-thought" and that what meets the eye/mind in some operational regimes. I wonder further, if that impression is largely latent and not approached or discussed in traditional training syllabi because of such latency. After all, in training, there is no discussion of human factors whatsoever, given economic factors in training footprints etc. Such courses are NTK - need to know, full stop.
That mode or impression of complexity may be defined by a sense that there is "more" to the 320 "layered underneath" the controls, indicators and cautions/warnings than appears to the crew - that the airplane is more complex to operate than it "appears" - that one must have a unique type of comprehension of flying airplanes to successfully come to terms with the Airbus design; - there is a "mystique" to the 320 both by reputation, both partially-earned and partially-not.
I again hasten to add that there are indeed, "layers of complexity" in the design. It takes normal crews about six months to a year to get used to the airplane and "strap it on".
My thought here is, "how do crews react to such layers in both normal and abnormal operations?" Do they try to "out-think" the airplane and thereby make assumptions about design features or the way something will work, particularly in an abnormal situation? Such "out-thinking" is not "intentional" because pilots have learned by and large to trust designers and test pilots. Thirty to fifty million successful approaches and landings can at least attest to that, (fascinating discussion on statistics - thank you PBL and Bernd).
I hasten also to add that this is almost certainly a training matter but a deeper level of appreciation of human factors would be needed before any such considerations would obtain in normal bread-and-butter courses.
Other than traditional fbw responses which for most transitioning to the Airbus have to become used to, the airplane "is an airplane" but I wonder if there is something further here - that crews may believe that the 320 is "more than an airplane" and therefore requires more thought/consideration than the design actually needs.
This may seem an trite statement to some, but I posit it for consideration. The notion that the TAM crew may have mis-conceived the "only one reverser" comment one of them made on short final needs an explanation. Without wishing to hearken back to the earlier discussion on auto-thrust systems in this thread, was there the latent impression (vice the "certain" knowledge) that the autothrust system would "handle" the #2 engine appropriately? (I know this particular question has been beaten to death but that is not the direction I am interested in taking this question).
I know I am stating this perhaps awkwardly or even obscurely but also that these comments can seem at once "obvious", (of COURSE the airplane is complicated!!), but i'll leave it there for comment to see if it is worth pursuing at all.
PJ2