Matt Barrow wrote:

Not that speed brakes aren't useful, but:
http://www.avweb.com/news/maint/182883-1.html (Reprint from Kas Thomas' TBO
Advisor)

Quite right. When they are useful is when you get a close turn on to the final
and "maintain present speed 'til the marker". Happened just yesterday.

Our speed brakes are vacuum-operated Precise Flight, apparently a bit of a
rarity, probably an aftermarket installation from the 80's.