airline pilots
 

if given a fixed speed by ATC, say 280kts on descent, apart from speed brake what else can pilot do to expedite the descent?

On the A320 you can use the Irish speedbrakes which add about 50 fpm.

[Irish Speedbrakes = Landing lights].:D not much else, sideslip not approved.

Of course back in the old days in thr T*****t you could put the outers into reverse and drop the main (body) wheels and descend at 15,000fpm while decelerating :ok:

The speedbrakes are there for that purpose. That is what would be used practically.

In emergency or extraordinary situations additional drag would be created by lowering the landing gear. However at this speed you would (in many cases) be very close to the limiting speed and such a course of action would not be recommended in most circumstances.

Of course you could make sure the throttles are closed !