Weather Delays

[747-436]

I am writing up a report for university about my work placement for an airline at Heathrow and am writing a section about delays to airlines. Anyway I have included a small section about human factors in delays. I am discussing human factors in weather delays (if there are any) I am saying that there are as aircraft can take off in most types of weather, but for instance if there is fog at EGLL the amount of movements is restricted because they can't be seen from the tower by ATCOs. I am mainly talking about ground movements. I know that landing separation has to be increased to protect the ILS etc so that restricts the flow.
The question I am asking is have I got a valid point or am I completely off the mark. I would be grateful if any ATCOs would be able to let me know. Thanks

[Standard Speeds]

747-436 - As an area controller I can only summise what happens on the ground, and whilst it is true that landing rates drop this is more often than not caused by pilot limitations. ie the plane is certified to land in nil visibility, but the pilot might not be.
Don't forget 'though, that weather can cause us radar controllers a huge headache, and very often departure restrictions are imposed, as well as arrival restrictions to protect the area (and approch) radar controllers whose workload increases dramatically. Therefore restrictions are imposed to limit the number of a/c in the airspace so that pilots requests for weather avoidance can be more easily accomodated.

Hope that helps! The human factor thing is a valid one, in answer to your question. The answer would perhaps be an automated air traffic service which would then remove the human factor! This (as I am sure ATCOs who are reading this are shouting at their screens)would be nigh on impossible. Imagine a computer trying to deal with unlimited numbers of requests for heading changes due weather, via an ACARs link (or whatever gadget would be used to contact pilots) Not realistic!

[ATCO Two]

Hi B747-436,

Do you not remember the Surface Movement Radar when I showed you round? We can still see aircraft movements under Low Visibility Procedures - the inbounds even have labels attached (until they vacate the runway), but a more robust system is being developed, eventually to be based around mode S transponders. Inbound, an aircraft cannot be cleared to land until the preceding has cleared the Localiser Sensitive Area (137m either side of the centreline). This is displayed on the SMR and with coded centreline lights on the field. Departing traffic (localiser guided takeoff), cannot be cleared for takeoff until the preceding has crossed over the localiser aerial. No conditional lineups are allowed. Only one pushback allowed in each cul-de-sac. All of these issues slow down the throughput of traffic. Not too many human factors as such, apart from the unfamiliar way of working and relying heavily on the SMR. Hope this helps.

[Direct HALIFAX]

The AREA CONTROL sectors work at capacity most of the time; but this can be drastically reduced when aircraft refuse to fly in the pre-defined corridors or at the normal operating levels. This occurs during thunderstorms and periods of turbulence.

[747-436]

Thanks very much for your help Standard Speeds + ATCO Two. I do remember the SMR from my visit to the tower, I have put that in part of the report. Although my report is being marked by a Geologist so he won't have a clue what I am on about. Oh Well.