Heathrow delays making the news
Heathrow delays making the news
http://www.bbc.co.uk/news/business-67468108
BBC story
Wind is 18 gusting 28 from WSW so delays and cancellations would be expected anyway.
BBC story
Wind is 18 gusting 28 from WSW so delays and cancellations would be expected anyway.
Join Date: Sep 2011
Location: FL390
Posts: 239
Likes: 0
Received 0 Likes
on
0 Posts
The delays aren’t because people can’t land in a crosswind, it’s because the headwind component is slowing everything thing down even with TBS. On top of that a 737 might have a ground speed of 80kts at 1000’ while the A320 behind has a ground speed of 120kts.
Originally Posted by Fursty Ferret
On top of that a 737 might have a ground speed of 80kts at 1000’ while the A320 behind has a ground speed of 120kts.
Dixi , that's showing our ages ....
CB , some clever mathematical pilot explained it 30+ yrs ago ...160 to OM or 4D helps ... However it's the time taken from 4D/OM to landing which governs the flow rate .
120kts ground speed takes 2 mins from 4D , with approx 2 mi. spacing and ' Land After ' , that 1 ldg. every min. Flow rate 60 per hr. LHR works .
60 kt G/S takes 4 mins from 4D , same 2 mi. space , 'land after' 1 ldg every 2 mins . Flow rate 30ph .. That really messes up the arrivals !
Thus it's better for flow rates to land with a tailwind !
rgds condor ..
CB , some clever mathematical pilot explained it 30+ yrs ago ...160 to OM or 4D helps ... However it's the time taken from 4D/OM to landing which governs the flow rate .
120kts ground speed takes 2 mins from 4D , with approx 2 mi. spacing and ' Land After ' , that 1 ldg. every min. Flow rate 60 per hr. LHR works .
60 kt G/S takes 4 mins from 4D , same 2 mi. space , 'land after' 1 ldg every 2 mins . Flow rate 30ph .. That really messes up the arrivals !
Thus it's better for flow rates to land with a tailwind !
rgds condor ..
And strong winds also affect the departure rate as aircraft climb into the increasing headwind. I’ve seen 80kts at 1000’ which really slows ones progress into the SID and delays the following departure.
So after 70 years of LHR windy weather, in Europes windiest country, still causes problems and it seems there is very little that can be done about it except build another runway like Arlanda ,Schiphol, Frankfurt or CDG (who already had 4 to start with). Incredible for once provision was made to leave a large area of land for a third E-W runway but not much provision to access it. And of course the residents of Kew are against it even though many of whom travel a lot and then complain about their flight being delayed .
Perhaps one solution would be like France and cut back on domestic flights and divert people onto high speed trains , that would be a good idea , oh........................................
Perhaps one solution would be like France and cut back on domestic flights and divert people onto high speed trains , that would be a good idea , oh........................................
In 2007 I went to work for EAT (DHL). One of the first flights I did was into Heathrow from Brussels and we spent about 20 mins holding. One of the pilots commented that the new runway will stop all this holding.
I said that I would be retired before it gets built.
I'm now 70 and plan on living to 100. I doubt I will ever see another runway at Heathrow.
I said that I would be retired before it gets built.
I'm now 70 and plan on living to 100. I doubt I will ever see another runway at Heathrow.
I know it was reported as being due to the wind, but I think controller sickness was a bigger issue.
(which is absolutely fine - I’d rather have a slot and a controller that is properly rested, than no delay and an overworked controller!)
(which is absolutely fine - I’d rather have a slot and a controller that is properly rested, than no delay and an overworked controller!)
TBS does a fantastic job and the landing rate is now much more predictable and resilient, however TBS only applies for vortex wake pairs and not minimum radar spacing so a pair of mediums will still be spaced according to the minimum radar separation (2.5 mile distance).
Join Date: Dec 1999
Location: LHR/EGLL
Age: 45
Posts: 4,392
Likes: 0
Received 0 Likes
on
0 Posts
As has been pointed out above, currently TBS only works on wake pairs. The next version comnig next year will work on all pairs, predict runway occupancy times, and use a minimum radar separation of 2.0NM rather than 2.5NM
