View Full Version : Sequencing on Approach


AlphaCharlie
2nd Mar 2006, 10:05
This may seem like a gripe but genuinely it is not ... I was just wondering on the rational behind it.

I fly for a certain UK carrier which Operates Dash 8Ds (the Dash Q400 to fellow pilots), and regularly on initially stages of decent we are asked to slow down or turn out wide in order to position a jet (sometimes more than one) in front of us for the approach. We then regularly get told to slow down for further separation as well. Bearing in mind that we are a very modern high speed prop which can easily match the decent speeds from FL200 downwards of all regional jets, and can maintain a higher speed until later on approach due to the fact that our props essentially act as giant brakes and we can wash off speed in seconds in a very short distance, with the jets needing much longer to allow their speed to wash off, why is it then that the jets get priority on approach. Sadly to say as well, in many a case it does just appear like BA favoritism with it usually a Speedbird, Shuttle or British being placed ahead of us.

As I said this is not a gripe at you guys who do a great job for little reward/praise, but it does get somewhat annoying, when we are on a tight turn around, to get sequenced behind a jet we are level pegging when we can easily beat it.



Del Prado
2nd Mar 2006, 10:42
Bearing in mind that we are a very modern high speed prop which can easily match the decent speeds from FL200 downwards of all regional jets, and can maintain a higher speed until later on approach due to the fact that our props essentially act as giant brakes and we can wash off speed in seconds in a very short distance, with the jets needing much longer to allow their speed to wash off, why is it then that the jets get priority on approach

Couldn't agree more, I hate to see a jet going very high speed 40 miles out to try to get ahead of a Q400 only to take extra miles to go down and slow down and end up delaying both aircraft. (you forgot to mention your excellent descent performance too!)

I think it's down to lack of awareness paricularly from the Area/Tma sectors but you have to bear in mind they are monitoring your respective speeds from higher levels and forming a plan when the jets are clearly faster than you. Also there is instinctive reaction that turboprops must be slow therefore get the jets in first.

Your post here is a good way to point it out and maybe a letter to ATC ops from your chief pilot pointing out how flexible the type can be? (an offer of fam flights might go a long way to educating people) But please be assured it's not favouratism to BA, their Swallow franchise suffer this just as much.

AlphaCharlie
2nd Mar 2006, 10:56
I think the BA thing is purely unfortunate ... operating domestic flights obviously airlines have similar flight timings to suit business custoemrs so we all arrive at destination airport at the same time and therefore we end up second to a BA jet because of the reasons you said.

I will suggest the famil flights idea to the big boss man!

Tweety
2nd Mar 2006, 11:18
AC

I have to agree with you and also del Prado here. After working in a number of ATC systems around the world where in TWR,APP and Area environments,I believe it does come down to lack of awareness from the tma/sector staff.

From an app sense a high performance turbo prop will easily keep pace with a jet from around 30 miles out and on many occassion I have had a Dash 8 give me 245kts (even 250kts in some cases, and they can keep this going to very close to the field as you say) and only a minor speed reduction to maybe 280 kts may be reqd on the jet (they have to reduce to 250 any way out of 10,000ft). If its the area guy at around 100nm out then it maybe a different kettle of fish especially depending on flow control as well.

If they try it a few times and then realise it can work and actually be less of a workload for the controller and keep a more consistent flow to the traffic picture than having a few acft on vectors and with speed control.

cheers

AlphaCharlie
2nd Mar 2006, 12:10
We are allowed to maintain 235kts all the way to 16nm (max due to airframe below FL80 is 245kts anyway), at which stage we should bring it back to 210kts to 12nm, then 180kts to 8nm, and 160kts to 4nm ... company SOPs.

Anyone know what the jets do? And at what stage they must retard the power levers to achieve their speeds? As I said above we can do it in no time/distance at all.

flower
2nd Mar 2006, 12:24
The Dash 8 D's caught quite a few of us out when they first came into service, the climb rate is that of a jet.
A similar thread but with Jets saying why do you vector Turboprops ahead of us happened a few months ago when i took some stick because i did just that. When you work turboprops on a daily basis you are well aware that in the last stages of the approach they can maintain a higher speed on final than jets, they can also slow back very quickly as well. ATR42s are capable of holding 240kts to 4 dme if required and can bring the speed back very quickly.
How the traffic gets presented to us though can make the difference to how the final sequence is established.

ukatco_535
2nd Mar 2006, 12:43
I sympathise entirely, and would only like to add this -

If I can keep a jet at 300kts for a no delay approach and it is obvious that he will overtake you doing 235/240kts then I will, as long as it does not mean I will delay you.

If it looks like it might be 'once round' the hold for spacing or even flying all the way to the entry fix before vectoring then I will slow jets right down to 220/230kts when they have made the level by restriction (if i still need them to do that). If that means they go behind you, then they will.

The BA and or other airlines thing is just unfortunate.. believe me, we want you on our frequency for as little time as possible, so we do not practice favouritism. A lot of the time we are too busy to play at being silly buggers anyway.

I think that most of my colleagues in the London TMA would feel the same :ok:

AlphaCharlie
2nd Mar 2006, 13:04
The Dash 8D is capable of 240 to 4nm as well ... just company SOP not to do that.

Hootin an a roarin
2nd Mar 2006, 13:37
Alpha Charlie

This is a problem for us North of the border and sometimes comes down to the fact that as an approach unit, we are not able to choose the order of the aircraft in our approach sequence as it has been set up this way by our area colleagues. They tend to put a jet in as number one only to hand that aircraft over at high speed and for him on first contact to immediately slam the brakes on whereas you will continue. It can screw us up as well as yourself and at my unit the d328's sometimes come a cropper as well. As you state you will keep your speed up for longer. Things are under way to attempt to standardise approach speeds and routeings which SHOULD already be in force but are not adhered to. :ok:

Regards

p.s. It would help us if you got off the runway a bit quicker as well! :E

ukatco_535
2nd Mar 2006, 13:57
Hootin and a Roarin

Wait until you get moved to McNERC - it will make it easier to bash heads there.

Having the approach function alongside us at TC is great - I think that although we are not as guilty of what you say (we still do sometimes send them across too fast), being co-located helps iron out problems.

A lot of it also depends on how the airspace is structured etc and where the routes come from as to how easy it is to bleed off the speed in time.

av8boy
2nd Mar 2006, 20:23
The Dash 8D is capable of 240 to 4nm as well...

Wow! And for decades my standard joke has been "two-ten to the marker, faster if you like..." I guess it turns out to be more fact than fiction in this case. I learn something every day.

Dave

throw a dyce
2nd Mar 2006, 21:11
Alpha Charlie,
There are other factors that may come into play.Given a straight race between a jet and a turboprop inside 30 miles,then the turboprop will generally win.
We also get traffic pegged in speed by the Area unit to maintain radar separation,but then we can use 3mile spacing which is a lot less.Also Class D,E,F,G airspace has speed restriction below FL 100 which complicate matters.
The Saab 2000 is also a very hot ship.I treat most turbo props as 210kts or more to 10 miles,and after that make sure they do about 160 to 4 to stop them slowing up too early.
535,
Are there any plans to move approach units to McNerc? Are we in for a mega pay rise as well,if we will be sat next to each other.(Thread hijack I know,but couldn't resist:E )

Empty Cruise
2nd Mar 2006, 22:00
AlphaCharlie,

240 to 16 / 210 to 12 / 180 to 8 / 160 to 4 sounds about right for a 73' - if no tailwind and not too heavy, we can start that at 4000 ft. and follow a normal descent path.

That being said, I know where u come from - I never had the pleasure of the Dash, but enjoyed the speed flex of the ATR very much. If SOP & ATC allows, we can do 320 kt.to 20 NM at 3000 ft. - but if standard speeds are in force, TPs and jets should be treated equally below FL100.

Another consideration is closely spaced arrivals with TP leading jet, one aircraft rejects T/O on runway and ATCO instructs both aircraft to go around - ok, a Q400 would not be a problem, but an ATR 42-3 followed by a 738 is not gonna be very pretty :ouch:

Empty

AlphaCharlie
2nd Mar 2006, 22:49
Empty Cruise. That's true ... not something I'd considered ... then again, have you seen how fast we can go up? And do we not regularly have jets following props on approach, all closely packed doing 160kts to 4nm? Yes we do.

Thanks everyone so far for their comments, the picture is becoming clearer now ...

ukatco_535
3rd Mar 2006, 09:27
Throw a Dyce

That was conjecture on my part, but in reality, it does seem the sensible thing to do.

It works really well having approach and TMA in one room.

As you say, it might help push you up the pay bands too!!!

rolaaand
3rd Mar 2006, 09:53
Hi Alpha Charlie.I work at Scottish and am to be found on the TMA most of the time. First off, there are no airlines that get any special treatment by any NATS atcos. I want you all off my frequency as safely and quickly as possible,and anyway no-one offers us free flights to encourage favouritism!
The DH8D has impressive performance for a prop and caught out many an atco when they were first introduced.
As has already been stated in this thread,the way area controllers treat your flight compared to approach controllers will differ a bit. For example, if you were flying to EDI on the Tweed1A star, if you are five miles ahead of a jet at Margo,you'll be number two,if you're five miles ahead at Eskdo,number one. A rough guide that would obviously depend on the prevailing traffic situation. The line can get blurred between what area and approach think and my watch at Scottish are doing liason visits to EDI at the moment which seems to be very beneficial,and may even stop hootin' moaning about us as much as he does!
Also bear in mind that from a TMA point of view that your aircraft can only provide us with the high speeds ( i stand to be corrected) in the descent between FL200 and FL90, and not in the cruise at FL200+.

danceswithsheep
3rd Mar 2006, 14:27
Just remember the next time you ask for, short cuts, direct routes, no holds, no speed and general cost cutting by pilots desperate to get back to rugby losing England.
If we speed you, its not because we love to here you speak (although there is a certain KLM jockey that gives me the .............), its because we have the plan. It may not be a great one, but its my plan and my license.
OK

renard
4th Mar 2006, 10:07
Speed profiles SOP are very similar on the RJ. With our barn doors on the back we could probably go a lot faster a lot closer, but not much passenger comfort
I don't think there is any favouritism - everybody thinks they are hard done to some of the time - our guys at SOU had very similar gripe not long ago except they were the ones slowing down.