Hi Mulligan,
Just my 2p's worth but:
In general I agree with you FO's. I flew the 319/20/21 for over 6 years and flap full is IMHO much better.
As far as I recall: in 2001 there was a notice from Airbus regarding the use of flap 3. This notice was based around some incidents other airlines had whilst landing Flap Full in gusty conditions. The general prob was that the 'old standard' ELACS were mis-calculating alpa-prot. This was exasperated during gusty weather (with Flap full extended), causing the a/thr to think the a/c was going to stall and thus apply TOGA. Makes landing a bit tricky!!!! So the quick fix was to use Flap 3 so as to increase the margins. The notice was effective for 6 months to a year, however after that everyone seemed to associate F3 with gust weather!!!!
Anyway, my experiences:
If it's windy/gusty I used Flap Full. I personally felt the engines were more responsive (due to being at a higher power setting due to drag from flap full), I also found on some occasions that adding 5 kts to Vapp to be useful (mostly when the FACs calculated a different Vls to the FMGC).
Once in windshear conditions my capt elected to use F3 for the app. We ended up in an unstable approach with the engines changing power from 40% all the way up to 85% (despite the auto-trim it was very unstable). We did a go-around, jointly agreed to try again with Flap full. The result was a far more stable app with pwr set at roughly 55% with less fluctuations.
Also, In general I noticed with f3 much higher attitudes on landing (one up at 10 degrees), and personally find that stressful.
As for fuel saving, I don't think it saves much if at all. The testing was prob done in a sim where it is calm, in real life, as I said the power can vary a lot with f3 which I believe will give the same average fuel flow as a straight forward ffull approach!
Anyway as I said just my opinion and all based on observations and chat with skippers and fo's over the years!
SSmih