Speed and wake spacing on final approach
From my previous unit, I recall part of a debate about responsibility for spacing on final. I seem to remember that this originated from another unit so I presume there were inter-unit discussions about it.
The bones of it was that as speed control can only be applied up until 4DME from touchdown, how responsible should ATCOs be for any erosion of wake turbulence separation within these last four miles?
I am making the assumption here that the spacing and or speed used before the 4nm point was good and correct.
Imagine a scenario of two aircraft of same or similar type both slowed during vectoring similarly then both given 160knots to 4DME and they are both transferred to the tower frequency. The spacing between them is just over the minimum required. The lead aircraft slows to final approach speed shortly after 4DME, whilst the second slows somewhat later.The spacing between these two aircraft erodes to just under the required minimum.
Should the tower controller break off the approach of the second aircraft?
How accountable should the radar controller be for the erosion of separation?
What responsibilities lie with the pilots? As ATCOs we assume they knew that they were in sequence, however I'll concede that the situational awareness of pilots and ATCOs is not always the same. They obviously have different perspectives on any given traffic situation.
Interested to hear your thoughts...