1) I can't remember what the difference is, but the A320 family (together with the A300-600R/A310-300 and the A380) have what are called 'Wing Fences', while the A330/A340 have 'Winglets'. In theory, the fences look after the spanwise outward flow on both the top and bottom of the wings, while the winglets do something different again (not too sure what exactly, but I believe, in the end, it's all much the same - reduce induced drag and thus save fuel/increase performance).
2) The brake fan issue is much simpler; because the brake temperature sensors only measure surface temperature, Airbus had to determine what the MAXIMUM difference between actual and indicated temperature would be with the brake fans ON (due to 'blowing' effect). They determined that the maximum difference was in the order of NOT MORE than 150 degrees. So, in essence, Airbus say that if - with brake fans ON - you see any brake temperature of 150 degrees, then the real temperature of that brake will not be more than 300 degrees.
And the reason 300 degrees is the 'true' limit is also straight-forward; it is the temperature at or below which hydraulic fluid is deemed to not be able to ignite if it were to come into contact with a surface at that temperature. It covers the case of a hydraulic leak in the wheel well, i.e. if under 300 degrees, then no wheel well fire.
3) Has already been answered. The license to go above REC MAX alt, is only to allow strategic decision making (allow a slightly higher altitude instead of having to descend to a much lower altitude in busy airspace if offered the choice by ATC). Having said that, I don't think I'd be very willing to go above what's shown in the PROG page except in 'unique' circumstances.
Hope that helps.
PJ2
One of the issues if the crew decided to take-off with brake temps in excess of 300 degrees would be how they would least-uncomfortably sit in their crew seats after the butt-kicking they should get for purposely (I assume) disregarding a limitation (A330 FCOM 3.01.32 P1)!
Last edited by RAD_ALT_ALIVE; 14th April 2009 at 10:55.