More questions for pilots - LAC
Join Date: Mar 2002
Location: Euroland
Posts: 2,814
Likes: 0
Received 0 Likes
on
0 Posts
DFC, there will be more fuel burnt because it takes more miles to lose that extra 1000'
Being cleared from 90 to 3000ft means that we can descend from 90 to 4000 at 2000+ft per minute and the last 1000ft at the required 1000 ft per minute max.
That means that it takes half the time to loose the height which at the same speed in my books means half the track miles. i.e. uses less sky.
Coming off the stack at 90 and from that level getting a good continuous descent approach will save fuel compared to the time spent holding at 80 and 70 plus the level flight at 70 to a cdfa point.
Having said all that, I agree that holding out etc are going to cause problems.
It is like the old question - which is more efficient - driving at the speed for best mpg and maximum braking to park or lifting your foot very early and letting the car coast to a halt in the same place with no braking?
PRnav and less vectoring will save as much if not more than these proposals.
This may require the one in front to speed up from its Econ speed for no real reason other than a lack of awareness
The objectives of ATC have not changed in Annex 11. Expedition with safety. Or put another way - no unnecessary delays!!
Join Date: Jun 2004
Location: U.K
Posts: 85
Likes: 0
Received 0 Likes
on
0 Posts
Fuel price
Just in response to 12Watt Tim's post, not sure if he was arguing whether it matters or not but after a bit of research, but you should should half their figures to be more accurate.
The cost of fuel as of the 30th October '09 was £400 per metric Ton according to IATA.
Based on this, 100kgs would cost £40 and if full there'd be 189 passengers on a B738 so it would cost 21p per pax as opposed to the 50p that was quoted!
Someone should work out how much controllers are already saving the airlines by giving continuous climbs when on a SID (from what I remember as a dispatcher from reading plogs, fuel was planned based on the a/c being at SID level until end of SID).
Cheers,
TJ
The cost of fuel as of the 30th October '09 was £400 per metric Ton according to IATA.
Based on this, 100kgs would cost £40 and if full there'd be 189 passengers on a B738 so it would cost 21p per pax as opposed to the 50p that was quoted!
Someone should work out how much controllers are already saving the airlines by giving continuous climbs when on a SID (from what I remember as a dispatcher from reading plogs, fuel was planned based on the a/c being at SID level until end of SID).
Cheers,
TJ
Join Date: Feb 2006
Location: Hants
Posts: 2,295
Likes: 0
Received 0 Likes
on
0 Posts
Eyeinthesky
I'm sure someone with more knowledge on the piloting side will give the proper figures (DFC usually lurks in this forum) but I think that there is a tolerance that pilots adhere to with regards to speed... I could well be wrong (+/- 10Kts rings a bell). If that's the case then using th esame speeds might not be ideal.
As for streaming speeds - when you are feeding to one hold, say LOREL, from the North, East, South East, West and South West then sometimes in fact, often) to prevent delays, high speed has to be used for a whole stream of aircraft to ensure that everything does not turn up at the same time... otherwise more fuel would be used due to unnecessary holding.
it is perfectly possible to achieve a stream of aircraft with them all flying the same speed
As for streaming speeds - when you are feeding to one hold, say LOREL, from the North, East, South East, West and South West then sometimes in fact, often) to prevent delays, high speed has to be used for a whole stream of aircraft to ensure that everything does not turn up at the same time... otherwise more fuel would be used due to unnecessary holding.
Join Date: Oct 2000
Posts: 156
Likes: 0
Received 0 Likes
on
0 Posts
eyeinthesky.
What a load of nonsense you write.
I am a TC Controller, speed control works very well and can be made to work over relatively short distances.
If AMAN worked and gave accurate information that everybody could use, speed control would be even more brilliant.
I think NATS Management should listen to pilots, the slow speeds they think are helping may not be the case.
Let pilots fly aircraft as they wish unless we have to change it so they absorb delays or do nor bump into one another.
What a load of nonsense you write.
I am a TC Controller, speed control works very well and can be made to work over relatively short distances.
If AMAN worked and gave accurate information that everybody could use, speed control would be even more brilliant.
I think NATS Management should listen to pilots, the slow speeds they think are helping may not be the case.
Let pilots fly aircraft as they wish unless we have to change it so they absorb delays or do nor bump into one another.
Join Date: Feb 2006
Location: southampton
Posts: 228
Likes: 0
Received 0 Likes
on
0 Posts
speed control works very well and can be made to work over relatively short distances.
I would like to try to provide the order based on AMAN but as it still doesn't pick up the aircraft through COA until 2/3 minutes after you have started streaming then i can't.
Pilots should be allowed to fly their aircraft as they want with minmial interferance from us as regards speeds and fuel economy.
Stepping down in the hold from 90 to 70 1000ft at a time is done at not more than 1000ft per minute so it takes between 2 and 4 minutes to loose the height.
Being cleared from 90 to 3000ft means that we can descend from 90 to 4000 at 2000+ft per minute and the last 1000ft at the required 1000 ft per minute max.
That means that it takes half the time to loose the height which at the same speed in my books means half the track miles. i.e. uses less sky.
Being cleared from 90 to 3000ft means that we can descend from 90 to 4000 at 2000+ft per minute and the last 1000ft at the required 1000 ft per minute max.
That means that it takes half the time to loose the height which at the same speed in my books means half the track miles. i.e. uses less sky.
We normally give 23 miles for the descent from 70 and 30 miles for the descent from 90. Pilots will expedite from 90 but we're surely going to get some moans if we expect them to always lose the height from 90 with 23 miles from touchdown. Can we plan number 2,3,4 on the basis that number 1 will definetly lose the height?
If you turn up at BIG at FL90/250kts and get offered a straight in (21 miles from touchdown) will you accept that? I know many of my colleagues would prefer to vector west and include a downwind to satisfy themselves the aircraft will lose the height.
PRnav and less vectoring will save as much if not more than these proposals.
As for PRNAV, how can we get consistent accurate spacing between aircraft on their own navigation?
At Heathrow the landing rate is king, you can try any of the these trials to save fuel and emissions but if the landing rate is not consistently above 40 per hour then they simply don't work.
And don't even get me started on increasing the complexity of sectors where validation rates can be as low as 30%
