I've been subjected to this 270kts trial a few times now and frankly I wish it would be withdrawn immediately. Some observations:
1. The trial is costing fuel. When we were allowed to use our own speeds, if I was going high on the profile I'd add accelerate a bit and conversely if I was starting to get a bit low I would reduce speed thereby altering the glide angle. This would be done with the thrust levers remaining at idle.
Under the new regime the only options available to me are to use speedbrake if I am high or thrust if I am low. During some descents I am now having to use speedbrake to meet (say) the TIGER restriction yet I am also having to apply power to fly level at FL120 at 270kts. Previously I would have dived off the excess height and reduced speed below FL150 to either prevent levelling off at FL120 or to level off, thrust at idle and start slowing down for the hold.
2. Because of the trial I am more likely to be further from the ideal profile than before the trial. At 270kts we need to be starting down before we enter London airspace. Typically we ask the French for descent, they (quite rightly) QSY us to London and by the time we check in we are above the profile. Because we are restricted to 270kts diving the height off is not possible so out comes the speedbrake.
In recent years the boffins at NATS/SRG have come up with some schemes which probably seem reasonable and sensible in a meeting room, but which operationally aren't so smart and risk introducing a lack of respect for the UK ATC system (eg. current taxiway position included in line up clearance, new ATSOCAS, 270kt trial, full spiel given to GMP when details passed during DCL request etc.). The 270kts trial falls in to this category because it quite plainly does not achieve its stated aim yet we persist with it. Because we can end up above the profile the risk exists that people will carry on towards TIGER, for instance, knowing that they will not meet the restriction but confident that the next controller will issue a lower level thereby cancelling the previous restriction. Alternatively people will use the expression "on transition" to their own advantage and choose to "transition" at FL150!
3. The 270kts seems to be increasing the workload for some ATCOs. I have had the restriction applied and then the controller has used vertical separation against the preceeding traffic. If I am close enough to the preceeding traffic that vertical separation is required instead of just speed control, it stands to reason that if they are on the correct profile, I must be above it. Furthermore because we must fly AT 270kts, we can no longer give you guys bursts of high ROD (to do that we used to dial the speed up and pull the speedbrake out). So waiting until we are almost on top of a level restriction before issuing it will now lead to non-compliance.
4. The trial seems to remove the ability for ATCOs to take maximum tactical advantage from a given traffic situation. Coming off the Atlantic recently with the 270kts in place we were given to TC OCK who not only lifted the restriction but asked us for high speed to help with the flow in to LL. We gratefully gave them and INT S 330kts. I don't mind doing that, but I could have arrived at the same point and time in space if I'd been allowed to fly my normal speeds. Not only that, I could have done it at idle thrust the whole way.
Conclusion: This trial is costing me fuel, time and grey hairs.
G W-H