Originally Posted by
uncle4
Who says we doing less than 5 nm?? Totally WRONG! Which part of MATC??
You are misleading the flying public!!
STOP DOING LESS THAN 5, until management says YES. Our job in the Tower can be much easier. Sick of APP giving spacing less than minimum wake turbulence ... there may be an accident soon
Now I can quote the MATC sections but it will take up quite a bit of forum space - and you have access to a copy and should know the relevant parts just as I do. Now if I'm not mistaken 5NM is min wake for a medium behind a heavy. In some circumstances we can use 4NM (also in MATC) and that is min wake between to heavies. The figures in the MATC are in any case about spacing NOT separation - for this HK uses ICAO radar and wake separations (see Doc 4444) and until HK files a difference and publishes it in the AIP these apply at HK. Another critical word in the MATC is 'should' - this has a particular meaning in aviation. I suggest that you go and read again the relevant parts.
I did not suggest that APP should ever provide less than the minimum separation and I don't. Your post is inaccurate and what has 'accident' to do with what I'd said earlier? If ICAO says that 3nm is safe between two mediums why should it be different here at HK - the laws of physics apply here the same at they do elsewhere in our current understanding of reality.
The 4th floor should however be explaining the the airlines why (and for years) arriving a/c have been delayed by vector, speed, and holding to supply extra spacing (not separation). For what reasons? Just what are ADC doing with the runway during this time?
It is not a safety issue in normal operating conditions - can be for some wx and runway mixes so we then use appropriate separation and procedures in those cases. Speak to the 4th floor APP guys - I hear that they have been tacitly and in fact specifically face to face approving min wake for the last two years - it is safe and expeditious to use appropriate international standard separations used all around the world. ATC must be safe, orderly, and expeditious - all three parts are required before we can say that we have done a good job (Safety having the highest priority and made a given in any situation).
HK has a final director now. HK has published reduced runway separation procedures - these are in place so that the unit can move to using all it's runway capacity. Slots have been and are limited at HK by CAD without compelling technical reasons.
I'm not tired today so you got the printable version of the reply:-)
tolosweetpea.