Descent Planning
Join Date: Sep 2007
Location: where the money is
Posts: 385
Likes: 0
Received 0 Likes
on
0 Posts
Flying the Citation 10 at the moment... Bit of a beast
It is a beast, true, but it flies like a jet. The 'X' can efficiently descend at Mmo, but ATC might not like it and further down you want to slow down significantly to 265 KIAS anyway (to have a buffer to the overspeed warning).
I like to adapt my 'descent tactics' a bit to my actual fuel status, i.e. lots of fuel on board or short on fuel. If fuel is no problem, start down using the rules of thumb mentioned earlier and you'll have some flexibility if given any 'directs'.
If you have to conserve your fuel, divide the altitude to be lost by 3000 (for a 3000 fpm rate of descent) and multiply this figure with the anticipated average GS, expressed in NM / minute. This gives you a nice fuel-saving descent, but it's hard to get from European ATC.
Your FMS helps you setting up a nice descend by using the Vnav-feature, by the way, and if your 2 boxes are in independent mode, the PF may choose to make calculations using the present cleared route, while the PM keeps her/his box on a route direct to final, for example.
It is a beast, true, but it flies like a jet. The 'X' can efficiently descend at Mmo, but ATC might not like it and further down you want to slow down significantly to 265 KIAS anyway (to have a buffer to the overspeed warning).
I like to adapt my 'descent tactics' a bit to my actual fuel status, i.e. lots of fuel on board or short on fuel. If fuel is no problem, start down using the rules of thumb mentioned earlier and you'll have some flexibility if given any 'directs'.
If you have to conserve your fuel, divide the altitude to be lost by 3000 (for a 3000 fpm rate of descent) and multiply this figure with the anticipated average GS, expressed in NM / minute. This gives you a nice fuel-saving descent, but it's hard to get from European ATC.
Your FMS helps you setting up a nice descend by using the Vnav-feature, by the way, and if your 2 boxes are in independent mode, the PF may choose to make calculations using the present cleared route, while the PM keeps her/his box on a route direct to final, for example.
Join Date: Mar 2004
Location: schermoney and left front seat
Age: 57
Posts: 2,439
Received 0 Likes
on
0 Posts
however our avionics are very good (Honeywell Epic) and frustratingly on our particular type it generally does a good job.
In Europe, I donīt plan anymore. Hundrds, possibly thousands of Sector - to - Sector handover altitude restrictions make any planning a joke. The 3 times ALT plus ten works fine where ATC wonīt block you from using it.
Sometimes one just wonders what ATC planners do have on their minds. Like London: descend realy, stay down low for ages. When flying out again: fly low for ages.
Join Date: Nov 2007
Location: UK
Posts: 332
Likes: 0
Received 0 Likes
on
0 Posts
There's another thread going on about this topic...mignt be some ideas there?
http://www.pprune.org/tech-log/40962...ithmetics.html
http://www.pprune.org/tech-log/40962...ithmetics.html
Join Date: Apr 2002
Location: Location: Location:
Age: 53
Posts: 1,110
Likes: 0
Received 0 Likes
on
0 Posts
I am on the 680 and I disagree.....
Theres plenty of occasions when if you'll ask you'll get to remain higher for longer especially in the UK
Try the Vulpe 1A into AGP and set a 3.7deg FPA, you'll touch the Levers once between 110 miles out and 4 miles when you chuck the barn doors out.
Im into my 4th year on it soon so I know its far from perfect but what else do you want it to do??? TL's closed from FL410 almost all the way to 4 miles - thats bloody Airbus efficient if you ask me - you cant blame Cessna for airspace restrictions
Theres plenty of occasions when if you'll ask you'll get to remain higher for longer especially in the UK
Try the Vulpe 1A into AGP and set a 3.7deg FPA, you'll touch the Levers once between 110 miles out and 4 miles when you chuck the barn doors out.
Im into my 4th year on it soon so I know its far from perfect but what else do you want it to do??? TL's closed from FL410 almost all the way to 4 miles - thats bloody Airbus efficient if you ask me - you cant blame Cessna for airspace restrictions
Join Date: Mar 2004
Location: schermoney and left front seat
Age: 57
Posts: 2,439
Received 0 Likes
on
0 Posts
Well, were driftin away from the topic (my fault)...
However, in our 680 left and right boxes disagree (have been told by Honeywell that this is normal), VS varies - a lot - if you are using VNAV. We have tried any setting between 2,5 and 4,0 that would give us an aeroplane not oscillating.
Your scenario would only work (on our aeroplane) if one used it as a guidance only. (VS mode then) Have been on a Honeywell workshop and all crews there had the same experience as I had.
The aeroplane I flew before had the Proline 21 installed and the VNAV capability in terms of precision and annunciaton where amazing compared to what we have now. (and that aeroplane had no autothrottles too - which Honeywell pretends to be the issue of the Sovereign, why it would not work as good as it does apparently on the Falcons and Gulfs)
On the UK stay up thing, Iīve tried that into London (often in City and Farnborough), into Manchester and Brum. Wonīt work or the just donīt give it to bloody Krauts. AGP? far too nice a destination, not allowed to, my peers go to the East a lot (where you mostly can plan youīre descent freely and then the old rule of thumb works great even in the Sov)...so I canīt try it soon.
However, the nice thing is the Sov can descent like a brick if necessary. Makes up for the avionics...
However, in our 680 left and right boxes disagree (have been told by Honeywell that this is normal), VS varies - a lot - if you are using VNAV. We have tried any setting between 2,5 and 4,0 that would give us an aeroplane not oscillating.
Your scenario would only work (on our aeroplane) if one used it as a guidance only. (VS mode then) Have been on a Honeywell workshop and all crews there had the same experience as I had.
The aeroplane I flew before had the Proline 21 installed and the VNAV capability in terms of precision and annunciaton where amazing compared to what we have now. (and that aeroplane had no autothrottles too - which Honeywell pretends to be the issue of the Sovereign, why it would not work as good as it does apparently on the Falcons and Gulfs)
On the UK stay up thing, Iīve tried that into London (often in City and Farnborough), into Manchester and Brum. Wonīt work or the just donīt give it to bloody Krauts. AGP? far too nice a destination, not allowed to, my peers go to the East a lot (where you mostly can plan youīre descent freely and then the old rule of thumb works great even in the Sov)...so I canīt try it soon.
However, the nice thing is the Sov can descent like a brick if necessary. Makes up for the avionics...
Join Date: Apr 2002
Location: Location: Location:
Age: 53
Posts: 1,110
Likes: 0
Received 0 Likes
on
0 Posts
Interesting..
Our Boxes Agree 100% we operate them in Dual and not initiiate xfer except when mnps'ing when we use independent
Never have any issues with oscilation at all, one problem that does exist on all the 680's that Ive flown is that we've found that if you enter the arrival or approach when inthe descent and actually vnav'ing the additional track miles to the flight plan cause the aircraft to recalculate and pitch down even though you are vertical directing to the next waypoint so the additional track miles on the plan shoudn't make any difference. So we plug in the plan where poss in the cruise and its almost perfect.Thats the only fault I can find....
Honeywell are full of crap - have you considered aking them to swap the box(es) under warranty
FL330 by EXMOR (west of London)
FL200 abeam TNT (same as 65 before POL) (East of London)
Are all restrictions which can be negotiated away, I tend to find informing them when the TOD would be (referenced to a waypoint) when requesting lubricates the process somewhat
Our Boxes Agree 100% we operate them in Dual and not initiiate xfer except when mnps'ing when we use independent
Never have any issues with oscilation at all, one problem that does exist on all the 680's that Ive flown is that we've found that if you enter the arrival or approach when inthe descent and actually vnav'ing the additional track miles to the flight plan cause the aircraft to recalculate and pitch down even though you are vertical directing to the next waypoint so the additional track miles on the plan shoudn't make any difference. So we plug in the plan where poss in the cruise and its almost perfect.Thats the only fault I can find....
Honeywell are full of crap - have you considered aking them to swap the box(es) under warranty
FL330 by EXMOR (west of London)
FL200 abeam TNT (same as 65 before POL) (East of London)
Are all restrictions which can be negotiated away, I tend to find informing them when the TOD would be (referenced to a waypoint) when requesting lubricates the process somewhat
Join Date: Aug 2006
Location: Glasgow
Posts: 20
Likes: 0
Received 0 Likes
on
0 Posts
Altitude divided by 3 gives you moreless the TOD.
2500ft/min standard rate, to adaptade with the wind af necessary.
At least it's simple and seems to work until now
Works with the Falcon familly
2500ft/min standard rate, to adaptade with the wind af necessary.
At least it's simple and seems to work until now
Works with the Falcon familly
