LHR this morning.
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Maybe I am a little harsh - but just lately it seems to be happening a bit too often. For a 200' cloud base with forecast improvement in the weather- it seems a bit much? Believe me - if we see no improvement forecast we will be carrying the 45 mins extra ! I think the main gripe is not being able to see why LVPs have been enforced and why this hasn't fed its way back up the line to become a slot delay at point of departure rather than an unexpected airbourne delay at LHR. I think I will have to revise my way of thinking - a bit like treating PROB 30 SN as PROB 99 !
411 A - I think that FRA and AMS have their own little foibles too - ie. last minute changes of runway and (sometimes) poor appreciation of aircraft energy management - they are just luckier with their enhanced capacity.
Still damn fine controllers at LHR ! (and Swanick etc)
411 A - I think that FRA and AMS have their own little foibles too - ie. last minute changes of runway and (sometimes) poor appreciation of aircraft energy management - they are just luckier with their enhanced capacity.
Still damn fine controllers at LHR ! (and Swanick etc)
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Many people have mentioned about the closure of A9W, on the night before we autolanded and then rolled as fast as we could on a flooded 09L to try to make A8 ASAP. We started turning off at 30kts, and that’s as fast as we could safely achieve. Planning on anything west of that was unacceptable due to the runway state, and the fact that if you miss your turn, it’s a long way down to the next useable exit.
Even so the unfortunate chap behind us was sent around. That was particularly embarrassing
, but we genuinely couldn’t do it any faster. With so many aircraft hurting for fuel, it seemed to us that about one in six were going around, which must’ve made for a lot of grey hair.
May I suggest that Heathrow gets A9W back in service as soon as possible? It can’t be as urgent as resurfacing taxiway Alpha round the north east corner with its gum wrenching potholes.
Even so the unfortunate chap behind us was sent around. That was particularly embarrassing
, but we genuinely couldn’t do it any faster. With so many aircraft hurting for fuel, it seemed to us that about one in six were going around, which must’ve made for a lot of grey hair. May I suggest that Heathrow gets A9W back in service as soon as possible? It can’t be as urgent as resurfacing taxiway Alpha round the north east corner with its gum wrenching potholes.
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Mick,
Believe me, there's nothing we ATCOs would like more than to get A9W back in service. Next time I'm in work I'll try and get a ETA for that. However, as for the back massaging taxiways by T1, I reckon 2007 at the earliest!
Believe me, there's nothing we ATCOs would like more than to get A9W back in service. Next time I'm in work I'll try and get a ETA for that. However, as for the back massaging taxiways by T1, I reckon 2007 at the earliest!
From a pax point of view it is increasingly unacceptable the extent to which short-haul services, particularly the domestic trunks, get significant cancellations (as on the day in question) whenever Heathrow gets into LVPs, which are surely to be expected quite regularly.
All that investment in Autoland over the years to enable operations to be maintained in poor weather is now wasted on these routes because when such conditions happen the airport has allowed such saturation of its runway capacity that the domestics end up getting cancelled anyway to meet the lower runway rates. And yet LHR higher management continue to peddle the public line that they are not at runway capacity yet.
All that investment in Autoland over the years to enable operations to be maintained in poor weather is now wasted on these routes because when such conditions happen the airport has allowed such saturation of its runway capacity that the domestics end up getting cancelled anyway to meet the lower runway rates. And yet LHR higher management continue to peddle the public line that they are not at runway capacity yet.
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missy - since noone's answered your question about a normal flow rate, under normal conditions / wake vortex mix LHR will average 41-42 landings per hour on one runway (the other being used for departures).
On a busy day there will be 680 arrivals scheduled between 0600-2259, or 40 per hour every hour for 17 hours. So, a flow rate of 29 for any significant period of time means that delays build very rapidly and airlines can do nothing but cancel. Cancellation rates can be 20% if the fog lasts all day (or if it snows).
On a busy day there will be 680 arrivals scheduled between 0600-2259, or 40 per hour every hour for 17 hours. So, a flow rate of 29 for any significant period of time means that delays build very rapidly and airlines can do nothing but cancel. Cancellation rates can be 20% if the fog lasts all day (or if it snows).
Sean Dell, you asked whether LVPs were an RVR based phenomena. LVPs are applied when RVRs are 600m or less or cloud ceiling is less than 200'.
No matter what the forecast might be, if the met observations fall within these limits the procedures must be applied.
As for this not being fed back up the line to become a slot delay at point of departure, well it is. Obviously not as efficiently as you would like but weather forecasting is not an exact science (nor is flow control).
It would be very embarrasing for ATC to apply excessive flow controls only to see the fog/cloud lift earlier than expected, the landing rate increase and the stacks empty before delayed flights can leave their point of departure.
On the other hand, if ATC cancelled flow restrictions on the basis of a forecast weather improvement which did not materialise we'd be left with 30min EATs plus an over delivery of maybe 15-20 aircraft in the next hour (and nowhere to put them).
WHBM, you make a very good point but inevitably some days the capacity at Heathrow will be reduced.
This may be down to low visibility, snow, strong winds, aircraft emergencies or airfield unservicabilities. If these conditions reduce capacity by 20% some days would you propose the airport runs at 80% capacity every day to obviate domestic cancellations ?
No matter what the forecast might be, if the met observations fall within these limits the procedures must be applied.
As for this not being fed back up the line to become a slot delay at point of departure, well it is. Obviously not as efficiently as you would like but weather forecasting is not an exact science (nor is flow control).
It would be very embarrasing for ATC to apply excessive flow controls only to see the fog/cloud lift earlier than expected, the landing rate increase and the stacks empty before delayed flights can leave their point of departure.
On the other hand, if ATC cancelled flow restrictions on the basis of a forecast weather improvement which did not materialise we'd be left with 30min EATs plus an over delivery of maybe 15-20 aircraft in the next hour (and nowhere to put them).
WHBM, you make a very good point but inevitably some days the capacity at Heathrow will be reduced.
This may be down to low visibility, snow, strong winds, aircraft emergencies or airfield unservicabilities. If these conditions reduce capacity by 20% some days would you propose the airport runs at 80% capacity every day to obviate domestic cancellations ?
Just interested to ask the experts what the anticipated flow rate would be if we had full simultaneous ops on the two runways (I presume someone must have calculated that) and what the LVP rate might be under those conditions too.
Even if we don't get simultaneous ops at all times possibly it's something that can be advocated when conditions are poor.
Even if we don't get simultaneous ops at all times possibly it's something that can be advocated when conditions are poor.
Ohcirrej
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Unfortunately WHBM (and I'm sure my buddy Gonzo can expand on this), the ground environment at Heathrow becomes very congested very quickly when you use 2 runways. Probably becomes counter productive.
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Occasionally, my friend Jerricho is correct!
Mixed mode would work for twenty minutes, and then you'd get the situation of nothing at the holding points because all the aircraft are in a massive traffic jam!
Lots of other reasons why mixed monde won't work, I'll list them all if you'd like! If you purely think of it in runway terms; presently we average 80-82 an hour. In mixed mode you'd be looking at something like 90-100.
I remain convinced that in mixed mode, our GMC capacity actually decreases.
Mixed mode would work for twenty minutes, and then you'd get the situation of nothing at the holding points because all the aircraft are in a massive traffic jam!
Lots of other reasons why mixed monde won't work, I'll list them all if you'd like! If you purely think of it in runway terms; presently we average 80-82 an hour. In mixed mode you'd be looking at something like 90-100.
I remain convinced that in mixed mode, our GMC capacity actually decreases.
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Actually, you will find that those Low Vis criteria values you have given are incorrect.
Low Visibility Procedures are in force when:
1) The IRVR is LESS THAN 600m (Met Vis when IRVR is not available)
and/or
2) Cloud Ceiling is 200ft OR LESS
Low Visibility Procedures are in force when:
1) The IRVR is LESS THAN 600m (Met Vis when IRVR is not available)
and/or
2) Cloud Ceiling is 200ft OR LESS
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Ah. LHR. That delightful S/H destination.
It can be CAVOK, 10kts down the strip and 40 mins holding. Why? Who knows.
Take 'company fuel' at your own peril.
A9W unavailable and a corporate Falcon 500 ahead wh has never been to LHR before ahead at night in filthy wx, my favourite.
It can be CAVOK, 10kts down the strip and 40 mins holding. Why? Who knows.
Take 'company fuel' at your own peril.
A9W unavailable and a corporate Falcon 500 ahead wh has never been to LHR before ahead at night in filthy wx, my favourite.
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OK explain to me (THICKO and no connection with current practises at LHR)
The advances in Ground Movement Radar have had no effect in low vis movements ?
Planes can land and take off in low vis - since Trident days. What is the issue ?
It seems that a little bit of fog stuffs LHR.
I understand safey margins, but it does seem that safety margins are taken to the extreme to perhaps further employment safety.
The advances in Ground Movement Radar have had no effect in low vis movements ?
Planes can land and take off in low vis - since Trident days. What is the issue ?
It seems that a little bit of fog stuffs LHR.
I understand safey margins, but it does seem that safety margins are taken to the extreme to perhaps further employment safety.
Ohcirrej
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LVPs require a safeguarded localiser area to ensure that ILS isn't interfered with. It can also mean problems for the jets getting off the runway with the reduced vis. Did you read the post by overstrees before your "well thought out post"?. A low-slung biz-jet can take an eternity getting off the runway in good weather (I lost count of the number of times I had an arrival come back because of this). Low vis??
All this requires increased spacing on final approach (increased from the standard 3 miles to 6 miles). It also means CAT III holding points are used clear of the sensitive area, thus meaning further to taxi for line ups. Conditional line up clearances can't be used. Like anywhere, both affect the departure and arrival rate.
All this requires increased spacing on final approach (increased from the standard 3 miles to 6 miles). It also means CAT III holding points are used clear of the sensitive area, thus meaning further to taxi for line ups. Conditional line up clearances can't be used. Like anywhere, both affect the departure and arrival rate.
Last edited by Jerricho; 3rd Apr 2005 at 13:13.
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LL34, if you visited the tower at LHR I doubt you'd think our SMR that advanced. Sure, sometimes the labels are attached to the correct aircraft, but sometimes you get them flying about all over the place, attaching themselves to vehicles, terminals, all sorts of things. And that's not counting the poor performance of the primary radar in thick fog or heavy rain (d'oh! Just when you need it to work!). Not to mention the constant stream of cars that seem to be crossing 09L/27R, but which are in fact in the access tunnel!
Halo, thanks for the correction (I always seem to get that one wrong)
Gonzo, to take you back to part of WHBM's question.."What would be the anticipated LVP flow rate for mixed mode ?"
Surely during LVPs we could increase the movement rate towards the 'normal' average of 80 per hour without coming close to swamping GMC ?
10 mile spacing on both runways (mixed mode) would equate to a landing rate of 20ish per hour plus 20 departures per runway equals 80. What do we manage at the moment during LVPs - about 65 ?
I know there are other issues involved but there would still be some increase in capacity, no ?
Gonzo, to take you back to part of WHBM's question.."What would be the anticipated LVP flow rate for mixed mode ?"
Surely during LVPs we could increase the movement rate towards the 'normal' average of 80 per hour without coming close to swamping GMC ?
10 mile spacing on both runways (mixed mode) would equate to a landing rate of 20ish per hour plus 20 departures per runway equals 80. What do we manage at the moment during LVPs - about 65 ?
I know there are other issues involved but there would still be some increase in capacity, no ?
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Well, if you can get BAA to abolish the noise restricions, work out how we would do it on easterlies, and work out some way to do single runway 27L (glide path considerations lining up from the south) and 09R (remember where S7 is?) 
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Just what is the state of play with landing traffic on 09R. I know it is very rare but I am only asking since I was a pax on a rather delayed flight a couple of weeks ago and landed on 09R at 2330L. Seemed odd since that is a 'noise sensitive' time?
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On easterly ops there is no noise issue for ATC for inbound aircraft. Whereas on Westerly ops you can only land on the departure runway a maximum of 6 times an hour.
If 09R departures controller isn't too busy he'll usually accept a T4 or heavy T3 lander to help approach out.
If 09R departures controller isn't too busy he'll usually accept a T4 or heavy T3 lander to help approach out.