ATC speeds & levels inbound to London TMA
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ATC speeds & levels inbound to London TMA
I get varying views on the following from colleagues, it really depends who you are flying with. Thus I am hoping to get some of the ATC personnel on here to clarify these points from their vantage point ...
1a) Is there a regulatory requirement to fly 250kt below FL100 in the London TMA?
1b) If so, does a high descent speed instruction given by ATC override this requirement?
ie if no further speed instructions are issued, what happens to the high speed requirement when the a/c reaches FL100, does it remain valid, or automatically "expire"?
• Notifying/requesting speed reduction '250 below 100' from ATC in London TMA --- necessary, prudent or superfluous ?
2) Let us assume a STAR that has a speed limit point, and a/c is inbound to this point with a higher speed instruction given by ATC. Which one stands, ATC speed or waypoint speed (assuming nothing is mentioned by ATC).
• Asking ATC about a published speed at a STAR waypoint when they have previously issued a speed instruction to the a/c --- necessary, prudent or superfluous ?
3) Assume on vectors to ic LOC, last speed instruction from ATC was to fly 220kt, but you are reaching the point (say, 12nm) where you would naturally wish to start slowing the a/c down for the final.
• Calling ATC about slowing down for final approach --- necessary, prudent or superfluous ?
4) On STAR, ATC instruct to 'descend to FL..., level by WAYP1', both as per published STAR procedure. (Assume the level at WAYP1 is 'artificially' low, ie below natural descent profile.) Then, before reaching WAYP1, ATC instruct to descend to a lower FL. Does it remain mandatory to comply with the 'FL... by WAYP1' instruction, or can we now descend at own rate to meet the new lower FL instruction, thus passing WAYP1 above the originally cleared level? (Assuming ATC doesn't mention anything ontowards.)
5) Similarly, on STAR, ATC instruct to 'descend to FL..., level by WAYP1' (as per published STAR procedure), but before reaching WAYP1 they give a direct routing to WAYP2 which is a waypoint further along on this same STAR. Do ATC still expect the a/c to be FL... abeam WAYP1, or can we now descend at own rate inbound to WAYP2, thus passing WAYP1 above the originally cleared level? (Assuming ATC doesn't mention anything ontowards.)
1a) Is there a regulatory requirement to fly 250kt below FL100 in the London TMA?
1b) If so, does a high descent speed instruction given by ATC override this requirement?
ie if no further speed instructions are issued, what happens to the high speed requirement when the a/c reaches FL100, does it remain valid, or automatically "expire"?
• Notifying/requesting speed reduction '250 below 100' from ATC in London TMA --- necessary, prudent or superfluous ?
2) Let us assume a STAR that has a speed limit point, and a/c is inbound to this point with a higher speed instruction given by ATC. Which one stands, ATC speed or waypoint speed (assuming nothing is mentioned by ATC).
• Asking ATC about a published speed at a STAR waypoint when they have previously issued a speed instruction to the a/c --- necessary, prudent or superfluous ?
3) Assume on vectors to ic LOC, last speed instruction from ATC was to fly 220kt, but you are reaching the point (say, 12nm) where you would naturally wish to start slowing the a/c down for the final.
• Calling ATC about slowing down for final approach --- necessary, prudent or superfluous ?
4) On STAR, ATC instruct to 'descend to FL..., level by WAYP1', both as per published STAR procedure. (Assume the level at WAYP1 is 'artificially' low, ie below natural descent profile.) Then, before reaching WAYP1, ATC instruct to descend to a lower FL. Does it remain mandatory to comply with the 'FL... by WAYP1' instruction, or can we now descend at own rate to meet the new lower FL instruction, thus passing WAYP1 above the originally cleared level? (Assuming ATC doesn't mention anything ontowards.)
5) Similarly, on STAR, ATC instruct to 'descend to FL..., level by WAYP1' (as per published STAR procedure), but before reaching WAYP1 they give a direct routing to WAYP2 which is a waypoint further along on this same STAR. Do ATC still expect the a/c to be FL... abeam WAYP1, or can we now descend at own rate inbound to WAYP2, thus passing WAYP1 above the originally cleared level? (Assuming ATC doesn't mention anything ontowards.)
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1a) This speed restriction is for departures, unless cancelled by ATC for operational reasons, theirs or yours.
1b) ATC speed overrides this. The ATC assigned speed does not automatically expire at FL100.
If you need to slow down, informing ATC of this requirement is necessary.
2) ATC speed stands. ATC might cancel the published SLP restriction e.g. "speed at your discretion" but if you have been asked to fly faster than the SLP speed it would be prudent to check with ATC if the faster speed is still needed.
3) As in point 1b.
4+5) A new clearance cancels a previous clearance. If the level restriction at or abeam WAYP1 is still required it must be repeated by ATC in the new clearance. If not, you can descend at your own rate. However, for the avoidance of doubt, it would be prudent to check this with ATC.
1b) ATC speed overrides this. The ATC assigned speed does not automatically expire at FL100.
If you need to slow down, informing ATC of this requirement is necessary.
2) ATC speed stands. ATC might cancel the published SLP restriction e.g. "speed at your discretion" but if you have been asked to fly faster than the SLP speed it would be prudent to check with ATC if the faster speed is still needed.
3) As in point 1b.
4+5) A new clearance cancels a previous clearance. If the level restriction at or abeam WAYP1 is still required it must be repeated by ATC in the new clearance. If not, you can descend at your own rate. However, for the avoidance of doubt, it would be prudent to check this with ATC.
