This is part question from me and part awareness for everyone to do with Area Speed control during early descent phase of flight.
A collegue cleared a british owned Bus to (exact words) :
"when ready descend FL*** LVL (fix)
speed when able 280kts"
half way thro the descent we spotted, using our groundspeed readouts, that this certainly wasn't being done so queried the pilot (confirm current speed) who replied "currently 340kts, reducing 280 as requested". Too busy at the time to discuss any further details as to why, and I do understand the whole Mach v IAS/transition across thing, but surely as the IAS increases during initial descent on a Mach, 280kts would not be exceeded at any time due to the restriction????
Q. Once 280kts intercepted, can this be maintained all the way down?
Q. Concerning the 'normal' transition level for speed, would you amend it for the purposes of speed control?
In this case, fortunately the controller also had headings in force to ensure separation, but if not, a Frenchman wouldn't have been too happy either, this letting us in on the others' speeding antics. However it is scary that an approved form of separation can be meddled with in such a big way. Yes, I don't fly yours or any other aircraft, but I understand enough to get along nicely. How many understand the measures of separation that we can use, and identify them as soon as they are issued to you in the cockpit?? If this pilot had listened, he would have heard in successive transmissions the frenchman get 300kts or more, himself get 280kts, and the Italian just behind get 280kts or less. This would have put them all nicely 10nms in trail, and possibly a straight off stack and into land (wasn't all that busy at LHR) rather than the 10nm already acheived being eroded till both were side by side, eventually giving the Brit a spin for spacing.
We don't do it for laughs, and are much better at it than ever before due to Groundspeed readouts (yes, something that actually works to advantage at Nerc), but maybe I'm still missing something??
