GS-Mini, Auto-thrust, and Short Runways – Airbus A320/330/340
Quote from PJ2 ["EK A330 Heavy Landing at BHX" Mar01/17:29]:
Until my company "made it known" that if one disconnected the autothrust, one was "on one's own" if anything happened, I flew every approach on the 320 series and 340/330 series aircraft with manual thrust. It simply kept one "closer" to the airplane in terms of situational awareness and it is what I taught during line indoctrination training.
[Unquote]
With little information available on the circumstances of the above incident, I've so far resisted the temptation to contribute to the discussion on that thread. But the comments re GS-Mini – some better informed than others – have taken me back six years to recall my intimate relationship with the A320 autothrottle (a "curate's egg", if ever I had one) and "managed" speed, including GS-Mini.
When I did my A320 conversion in 1988, just before the type was certificated, it was put to me and my co-pilot that, with the exception of the FBW flight controls, there were two ways to handle the cockpit flight systems:
1) ALL MANUAL;
2) ALL AUTOMATIC.
Since then (I think Northwest was the first airline to mandate it), there has been a steady movement towards recommending or mandating the use of autothrottle (A/Thr) during "manual" flight, even on the approach below 1000ft aal. Personally, during my 14 years on type, I rarely used it for manual approaches; once fully visual and configured for landing. The exceptions were approaches where visibility was tricky, or when visual contact was not made until late on. I did many windy arrivals into the fairly short runway at Jersey; almost invariably with manual thrust.
Manual thrust worked even better than on my previous types, because (a) the levers are a joy to use (once manual thrust has been established) and (b) GS-Mini avoids the necessity for large changes of thrust during wind-shear. The tendency of the A/Thr, on the other hand, to be slow to reduce IAS – as the "managed speed" falls in accordance with the headwind component – was yet another reason for my policy.
Managed speed should be treated as a TARGET speed. Unfortunately, many pilots seem to regard it as a MINIMUM speed, chasing it like mad if using manual throttle. And the A/Thr often seems to have the same idea, particularly when the target is trending downwards. If so, this is quite wrong. Even VAPP is not a minimum speed in a gust. The only minimum speed is VLS. The latter has a degree of fat built into it, certainly on European aeroplanes. [Yes, I also remember the "Seven-oh".] 
This tendency of the autothrottle to bring the aeroplane to the threshold at a speed above VAPP on a head-windy day is unsatisfactory, and potentially hazardous on a short runway. A318 operations will soon be starting, if they haven't already, at London-City. Without trying to anticipate any special SOPs that may be in hand, I very much hope that the operators, including the pilot-managers of my former employers, will be aware of what I am talking about. Remember, zero headwind on the ground can be preceded by headwinds low on the approach, particularly at night.
So the way the A/Thr interprets "managed speed" and GS-Mini can lead to an excessive threshold speed with little headwind to help you stop on a short runway.
There have been some recent modifications to the GS-Mini logic, apparently, but I am going to reserve specific comment on GS-Mini until more information comes to hand on the modifications. In the meantime, it is worth emphasising that the overall package of the A320 thrust and speed control was probably the best of the seven jet types I flew – despite the non-driven throttle-levers, rather than because of them.
Chris