View Full Version : ATC Bias

ccy sam
23rd Sep 2005, 07:02
Enroute SY-CS. Jetstar 11 miles behind us on the same route. As we commence descent we're vectored off track and slowed down. Jetstar told to speed up and given track shortening to get ahead of us. Result, instead of being a few minutes early we are 3 minutes late and burn more fuel (spoilers out most of the way down). Not the first time its happend. Could it be ATC home town bias since the jetstar boys are based in CS?
Checked with brisbane center and the sequencing was arranged by CS approach.

23rd Sep 2005, 07:18
Highly unlikely, but please give more info. What were you in? What speed were you doing and what level were both of you at. But really it sound like a clear case of somedays you are the statue and somedays you are the pigeon.

Going Boeing
23rd Sep 2005, 08:15

I don't believe that it is bias - just errors in programming of Maestro that caused the other aircraft to be sequenced ahead of you. Last Monday, CX (F370) was 3 miles in front of us (at F390) and Maestro for some reason gave us a sequence number ahead of CX who received radar vectors off track to let us descend on the Boree STAR and achieve a position in front for descent. The CX pilots had every reason to complain but they displayed great professionalism by just accepting the ATC instructions.

I believe that Maestro is still very flawed and should be used in a "ghosting" role until the bugs are worked out of the software.

23rd Sep 2005, 08:38
they displayed great professionalism by just accepting the ATC instructions Think about what you said. The veracity of your statement depends on your definition of the word "professionalism".

Just "accepting" ATC instructions rather than questioning them isn't always a good thing. Human error by ATC, whilst uncommon, is not out of the question.

But nowadays anyone who questions a sequencing issue is immediately classified as a whinger or trouble-maker so most pilots shut-up.

More professional might have been if the pilot had been able to find a way to get his point across succinctly and without sounding like a whinger.

23rd Sep 2005, 12:33
Sam, ifa you justa pay da man whena he visit, you no hava dese problem any more. Capisce? I mean, what's one lousy bottle of scotch?

SM4 Pirate
23rd Sep 2005, 12:38
Not a Maestro issue, it's only in ML, SY and BN; 'ghosting' ha, it's been used in anger for about 4 years... it's not a new tool, it's just got new users.

Is it better at organising the sequence, yes, does it do a better job and improve slot management, no. Maestro does help reduce late sequencing instructions, so has reduced things like 'general holding', does it pick the 'best sequence' no way; but does it lose slots, no. Remember a lot of it is politics, SY has a movement rate of 80 an hour, yet the airport could easily land 60 an hour, leaving only 20 deps, which isn't they way we do it; so there are occasionally 'artificial delays' built in to ensure that the CAP isn't broken. This of course is considered by most pilots as inefficient or useless ATCs, our hands are tied.

CCY, Not ATC bias either I'd bet, quite frankly this little duck couldn't care less who is number one. But I can say that a B717 will 'kill' a B737 in the last 120NM, don't know why but they do; even with the same IAS, something to do with keeping it steeper (higher GS); also the econ descent thing doesn't seem to be done as much in the B717; not sure whether that was perceived as a factor. Might just have been a fax pa.

I'd also say something else was in the air if you lost what appears to be 5 minutes (a couple early to 3 late)... Seems to much time if it was simply the loss of one slot.

I certainly wouldn't have gone for this option, but sometimes there is a disconnect between Arrivals the achiever of the sequence and the FLOW, the chooser of the sequence.

Uncommon Sense
23rd Sep 2005, 13:47
Sorry to dissapoint you mate, but there is no ATC Bias - for a start what's in it for them?

If you think you are hard done by just give them a call and ask - as long as you can make the call within 15 minutes of landing, otherwise you will just be a distant memory.

Hate to say it, but I have done this argument a thousand times - you as the pilot will never have the big picture - it's the first thing every pilot who visits an ATC centre says.

So no conspiracy - unless some poor bastard is getting free travel in the back of a Metro to Kowanyama by doing special flow favours!

23rd Sep 2005, 13:47
"Local" bias? Get a grip son. If CS ATC favoured 'mates' they would have sequenced Sunnies or Pixie or Aussie or National Joke ahead of you. They have been there for yonks. JQ has been there for five minutes, nowhere near enough time for the FN Queenslanders to overcome their natural aversion to Mexicans, let alone sequence them ahead of you.

23rd Sep 2005, 15:21
Try flying into France....then you will see bias..."AIR FRANNCE..345...you are now No 1"


Capt Claret
23rd Sep 2005, 18:52
Proof positive that ITCZ is still alive and with us (post above proves life force). ;)

How was the Bourbon & Beef Steak?

23rd Sep 2005, 21:49
Going Boeing,

Cx was 3 miles in front for which runway? Same as you or were you for the short runway as is usually the case via Boree? Did you have any idea as to how many aircraft were in the sequence for each runway? Believe me , we don`t have any favourites but if there is a decision to be made most controllers/flows will back a domestic anyday. Ever seen a CX Airbus ( or any other Airbus for that matter ) beat a domestic from 100 miles. It just doesn`t happen. Or it didn`t until QFA started their "accountants" descents.

Maestro is a wonderful thing. Really. If your on single runway ops with 30 minutes holding for everybody. Under those conditions it will beat an experienced flow anytime in always having a trail of aircraft for approach to handle.
Any other scenarios ( // ops. config. changes, and a million other things ) it`s a piece of French merde. If we gave you each and every revised time for a feeder it comes up with you would eventually land and head straight for the phone to tear somebodys throat out. No amount of management BS will convince those of us who have to use it otherwise. Trouble is we`re stuck with it so we all have to make do.

Going Boeing
23rd Sep 2005, 22:50
Boree 3

I wasn't making an accusation of bias, I was arguing a case against its existance.

The sequence for the Boree 3 STAR was a domestic aircraft for 34R, my flight for 34L, CX (A330) for 34L followed by another domestic aircraft for 34R. To achieve this sequence, CX (2000' below and 3 miles in front) was vectored east of the STAR track before rejoining the STAR in sequence behind us. I have observed this happen before which is why I believe that Maestro still has flaws and should be used in a "ghost" mode rather than as an active ATC tool.


Good points. I was trying to say (in brief) that I appreciated the fact that the CX crew did not whinge over the airways.

SM4 Pirate

Thanks, I was unaware that Maestro is not used for sequencing into CNS.

haughtney 1

As well as France, Singapore ATC is well known for giving the local carrier express service at the expense of everyone else - even to the extent of training aircraft getting priority over RPT.

23rd Sep 2005, 23:09
I only have bias against idiots. Perhaps the controller was psychic?

23rd Sep 2005, 23:33
Goeing Boeing
This perception of favouritism has been around for ever. I think you will find that it is just a matter of the traffic at each port. Naturally at CDG there are going to be more AF aircraft, more SQ at Singapore and more BA at Heathrow. Hence when you are sequenced behind someone it is likely to be a local. Therefore you get the feeling of local bias.

24th Sep 2005, 00:56
CCY sam, a few minutes early to 3 late ?? shear Luxury !! :}

Try arriving into PH without a light blue tail, or being in a bugsmasher...........

" XYZ reduce groundspeed by 60 kts "
"XYZ descend at 230ias "
" xyz reduce now to 210 ias " ( at 40 miles )
" XYZ reduce to final app speed " ( at 20 miles )
" Why ????? "
" you are number 3 to an F50 and a kingair "

conditions CAVOK and don't most T/props descend at around 250??

The above account is true ( and happens every other day )
and believe it is still happeniong to 717s, though not as bad.

Only the names have been changed to protect the innocent :hmm:

Rant over :E

24th Sep 2005, 02:21
I wondered how long it would take for the Perth bashers to come out. You just don't get it do you. Have a look at David McMillan's
ATC in Western Australia (http://users.ssc.net.au/mcmillan/ATC%20in%20WA/1_air_traffic_in_wester.htm) page, particularly the bit on flow control and sequencing. Say the three of you had natural landing time within 1 min of each other. It follows that you (assuming you had the last landing time) have to lose at least 5 min. Why should the BE20 and F50 be vectored out of your road to lose more time when you were last in the sequence. They have just as much right as you, Captain 4 Bars in your shiny jet, to be there as you.

24th Sep 2005, 03:42
I think we do it (sequence) wrong. Everywhere I've worked we attempt to reduce track miles , but still give a time delay ie. the way maestro does it. If we just let them steam on in and then run extra track miles like they do in the states (simplistically put for brevity), the pilot sees the 10 a/c ahead of him and thinks you are doing a wonderful job. Check out the 60nm finals they run at some of their busier airports. Who cares if it's less efficient? Might finally put an end to all the bitching about sequencing.:hmm:

Black Maria
24th Sep 2005, 05:23
On contact with approach during descent (turbo prop) into a Regional Airport, we were given a not above speed some 20 knots below profile. Did so and then from 15 miles were given, for some unknown reason (at the timie), a heading change of around 30 degree, adviced of 35 track miles to run and asked to sight a 737 that was below, to our left and diverging further left.

Cost of 5 or so minutes and a pretty ugly approach due to being on top.

Anyway, a telephone call to APP got us their reasons, the 737 from 100 miles or thereabouts out requests a high speed descent, which apparently puts him 1 minute in front, then after being given same, slows right down very shortly after, and throws the whole planned sequence out.

At least the phone call to the controllers gave us the opportunity to hear their reasons for what seemed to us, at the time, just inexplicable.

I guess on this occasion a tradesman had the right to blame one of the tools he was working with.

24th Sep 2005, 11:42
ccy sam,
You should have given Cairns Approach a call for an explanation. Perhaps he was 10000ft below you and 80KT faster (which I've seen heaps of times)
Another perhaps - you click on the traffic management window to enter landing time and flow instructions and the system does a recalc and shuffles the strips as you click on it and the instructions get posted to the wrong aircraft without being picked up.

24th Sep 2005, 12:20
willadvise, the bias in Singapore is VERY real. I've personally been involved in about half a dozen or so instances where after being in front of a SQ aircraft, we've been vectored south (for RWY 02 coming from Aussie) and joined final at 20-30 miles when the following SQ has been given vectors in front of us and joined at 12!

There may be more aircraft and therefore you may get put behind SQ more often but when you've listened to the callsign one minute behind you for a couple of hours get the short vector, you know EXACTLY what it is! :suspect:

24th Sep 2005, 12:36
"A half a or dozen or so instances or so" in how many approaches you have done to Singapore. I would hazard a guess that you have done hundreds if not thousands. That is not a bad %age. I can't begin to speculate at why you were made no 2 on these occasssions but i think some days you should just accept being the statue becauase you will never have the full picture.

24th Sep 2005, 13:03
will, i'm a 767 driver.....I've only been to WSSS a half a dozen or so times in the last eight years! :} (Last time I flew in there was January this year and we had a win! High speed approach (as much as QF SOPs allow and direct tracking.....no one else in the sky though! :ok: )

Seriously though, I've copped it often enough to know when something is amiss. By the way, I think you'll find a bunch of 744 drivers would attest to the same thing and they fly in there a lot more often than I do!

24th Sep 2005, 21:19
Have to agree with Keg on WSSS.

The problem there has got worse since GOD decided to rub Lee Kwan Kew's nose in it by starting up the endless money pit otherwise known as JQ asia.

Perth is a disgrace. STARS that dont join up to air routes. Ambivilent (at best) controlling, rubbish CTA steps and ATCO's clearing you for visual approaches in IMC or outside the criteria (esp at night).

I understand that one of the reasons that international carriers such as EK always arrive there carrying an altn is due to the fact that the controlling is so bad that they consider a go-around is probably going to happen one out of three approaches or so.

Uncommon Sense
24th Sep 2005, 23:58
Caligula - yes I think you are right. I am sure there is a section in the EK Ops Supp that says when flying to PH ensure ALTN carried due "Caligula reckons the controlling is shit at PH".

Where would the ALTN for PH be by the way when traveling from the sandpit? And why would you carry an ALTN instead of just fuel for another approach?

If you want an understanding of the myriad of STARS around PH , look no further than the RAAF. I have never worked there but believe this is the main problem.

That and NAP.

NAP is the main reason that the quite sensible suggestion by ferris is spot on. STAR linked IAL that have no legs are a crock when traffic levels get above anything sedate. All flexibility goes out the window when all the APP controller has left is speed control - and speed control is getting to be impractical with all the accountant descents - unless everyone wants to do 210K from 30NM. Having a downwind and base turn determined by the APP controller gives the most efficient runway utilisation EVERY TIME. It's just that the NIMBYS preclude it - abley assisted by our spineless politicians.

Look at just about any busy aerodrome in the US and they run downwind legs or long finals with the APP person slotting them in - and it works. Because it is easy, and simple. Try doing the same amount fo traffic with all different intersecting angle tracks to a common point on a 6-10nm final, with different aircraft types (JET / PISTON) and it quickly becomes inefficient - but that it what we have allowed to develop in Australia.

Rant Over.

25th Sep 2005, 09:02
Once again the poor but honest Flow is, rightly or wrongly, being maligned.
Flow control in CS is a bit of a black art, given the terrain, runway and taxiway restrictions, mix of traffic and often arcane company requirements.
For anyone, apart from the person who flowed the sequence in question, to try and explain it is probably futile.
For the benefit of those who may not have seen them posted before, here are general rules of Flow as it applies in Cairns and everywhere else.

Rules for successful flow control

1. Donít trust pilots
2. Donít trust sector controllers
3. Donít trust tower controllers
4. Donít trust anyone else
5. Develop a thick skin
6. Never back a Twin Otter to beat anything, even another Twin Otter
7. Never worry about departures, they are the tower's problem
8. Pray that the management pilots have good FOs
9. Computer Derived Threshold Times will be accurate only if the captain throws the computer out the storm window as he overflies the threshold in the go-round after being too intimate with the aircraft in front
10. All pilots think that they should be Number 1
11. Cardboard Bandeirantes can be used to hide unexplained gaps in the sequence
12. Unless they build more runways the maximum number of aircraft that can land at an airport in a given time will remain the same, despite the wetdreams of airline schedulers
13. Have faith in your own ability, no-one else does
14. Same money, right or wrong
15. If you believe the tower controller who says that the runway works will be finished prior to the start of the next sequence, you deserve all you get
16. Your are only as good as your last sequence
17. If your last sequence was not good, see above
18. Keep slipping the odd joke to the approach controllers, it keeps their mind off what is coming up
19. One day you will get a trainee who merely triples your workload
20. Never sit in approach and work your own sequence
21. Always keep a false nose or wig in the car, an angry mob waiting outside the carpark is not a pretty sight
22. The flow is never wrong, The flow is merely acting on information that may now be superseded.


26th Sep 2005, 00:37
Yes, I will admit it, I am sorry, I have biases.

A 330kt on descent bias, just ask me for 330kt below 10,000ft and I'll do my best to get it for ya,


HKG Phooey
27th Sep 2005, 08:00
In Europe you get duped everywhere you go! The local carriers get an insane amout of "favarouble" controling. When you return to the uk the forigin carriers get pref treatment so the UK guys don't look like they are helping the uk folks out....

Result.... Stiffed everywhere you go....


27th Sep 2005, 08:32
The local carriers get an insane amout of "favarouble" controling.

I suppose the local carriers treat their local controllers favourably as pax too?

Nothing can be as beneficial as foc club memberships, annual flights, etc. :rolleyes:

1st Oct 2005, 07:07
You are unfortunately, on at least one point, correct, Illadvised.
In the good old days the shiny jet with 150 odd pax got priority over the small charter A/c.
Now all you get is to pay a truckload more in airspace charges than the smaller brother and receive crap controlling into the bargain.
I don't expect anything other than for you to come up with excuses, and I am not going to waste valuable web space going into the 100s of examples of great controlling I had into perth over 10 years.

Quote: " lose at least 5 minutes " .....exactly my point, 5 minutes at 7 miles a min is 35nm, and thats about how good you guys are, 3 A/C inside 30 nm.
You give us 4 speed reductions starting at 160nm and the last at about 30nm, totalling 160IAS, and you think thats normal ???????

Now that I fly into Airports where 3 A/C in VMC is not considered a busy demanding task, my blood pressure is alot better.

To quote an anon yank departing PH :
" you know, you guys are the second best controllers in the world "
" Really?, who are the best "
" ...............everyone else "

PPRuNe Radar
1st Oct 2005, 10:17
In Europe you get duped everywhere you go! The local carriers get an insane amout of "favarouble" controling. When you return to the uk the forigin carriers get pref treatment so the UK guys don't look like they are helping the uk folks out....

HKG, simply not true about the UK. You think we have time to sit and work out an order of preference based on the carriers nationality ?? Our modus operandii is to get everyone out of our airspace and become someone elses problem as quickly and easily as possible. :ok: Not get involved in silly power games. We take the cards we are dealt and then get on with it.

To keep the Dunnunda stuff on track, I've copied the European/UK slant as a new topic which can be debated in the ATC Forum.

ATC Bias UK/Europe (http://www.pprune.org/forums/showthread.php?s=&threadid=192342)

3rd Oct 2005, 08:38
I've heard this story a few times (so it must be true!!).

Back in the 80's when we had a true 2 airline policy (TAA and Ansett), Sydney Manager gets the local reps from each airline into his office, says to each rep, he's the pile of complaints of favourtism, here's your half and he's the other half.

My guess that is breaks even in the long run unless we are talking about Compass Mark 1!!

3rd Oct 2005, 09:55
Keg and I have had the discussion about Singapore ATC before, yet I doubt if Keg has even yet done as I suggested and visited SIN ATC at work to see for himself that, if anything, they would prefer to disadvantage an SQ aircraft than a visitor. By Kegs own admission he only goes to SIN very rarely. Willadvise makes the very good point that at Changi you can expect a whole lot more SQ than anything else, I got very irate once about being, as I thought, 'stuffed' by another SQ that I thought was both behind and above me, turned out the callsign was only different by virtue of the same digits in a different order e.g. '826' and '862', very pleased my sharp eared FO spotted it in time that the 'traffic' was, in fact, ahead and below.

Keg, I wouldn't bother asking those QF captains if I were you! When I was there many of them had taken their 'super' and gone to SIA, no complaints at all about SIN ATC, had visited the operation and fully understood the workings, found it to be totally fair and, if anything, biased against SQ and I would urge all of you who visit Singapore to take the time to visit ATC, they would welcome you and be pleased to show you how it all works, they are a very professional bunch, much better than my experience of Sydney, for example.

Finally, Keg, you can reasonably expect a .86 747 to be put ahead of a .80 767, or even if you are in a 747, when ATC are trying to put you on the runway nearest to your terminal and SQ on the runway nearest to theirs.

Howard Hughes
3rd Oct 2005, 10:55
Nice work separator:ok:

By the way, I should be number1!! ;)

Cheers, HH.


3rd Oct 2005, 12:21
G'day Blue,

I did ask once. They were unable to accommodate me that day. The other day they suggested I wasn't in SIN so no good. Given that I don't go to SIN all that often, wouldn't you think that it would make the perception of bias even more apparent? It seems to happen almost every time I go there! :E I will ask again when I resume longer slips in SIN though.

I will admit to not being as up to speed on SIN ops as some of my 744 bretheren (although I'm looking forward to that changing next year) however if I'm complaining, please give me credit for 1. working out that the call sign of the aircraft behind me is now being vectored in front of me and 2. that he is being vectored for the same runway as me. If I was including the times I'd been vectored or slowed down for an SQ (or other carrier) on the other runway then I'd be bitching about a few dozen more occasions than 'half a dozen'! :* :suspect:

3rd Oct 2005, 12:34
Funny people pilots...they get paid by the minute, but want to go everywhere as fast as they can.

Question for any ATCers at Sydney. When doing the RIC1 departure, is it the distance to RIC or the altitude that allows a turn to the east (crawley for example), disregarding traffic of course?

Also, with these PLTs being passed now, is it better to be a bit early, or on time? Do the arriving aircraft seem to be following the PLT given? If we are aiming to make the PLT, and the TAS has been reduced/increased, does the ADS report you get update this, or do we need to keep you updated, or is the PLT enough?



Silly Sosij
3rd Oct 2005, 12:57
Can only help with your first question, Don, after asking the same one myself, and the answer is both. Out to 12DME SY (from memory) for "noise abatement", but beyond that the crucial thing is height as you generally have to be above ten thousand to cross back over the inbound tracks.

On a related topic, that visit helped me understand a whole lot about YSSY ops. Relaxed but on the whole, I would have said pretty professional. What did they do to you, BlueEagle?

SM4 Pirate
3rd Oct 2005, 13:56

Sosij is absolutely right re the SID.

On the PLTs, let us know verbally if you change speed by m.01 or more (I think I read that somewhere).

On the first day someone changed by M.07 without advising us. This lead to a BOS or near BOS as aircraft behind tried to catch up due to normal speed... imagine that.

The PLTs seem to work most days, but I have seen two days that were horrible.

Further on the Bias, I was 'growled at' by a 767 driver because I gave them 250K today and the following VB Max;
he "why are we being made number two to VB?"
me "You're not, you'll win"
he "we've just been slowed and VB has max?"
me "You are sixty miles ahead, he can't catch you, but you can catch the preceding slowed 737".

Big picture people, it's very important.

3rd Oct 2005, 14:00
Thanks for that fellas.


Going Boeing
3rd Oct 2005, 15:15
This has been a very informative thread and I thank the ATCO's for all their input.

I appreciate that the majority of ATCO's throughout the world are too busy doing their job for BIAS to even be considered however, I have just done an arrival into SIN whereby two SQ aircraft that were behind us (one was 35NM behind) were vectored into the sequence ahead of us - the only excuse that I can imagine Singapore ATC using as a defence would be that they (SQ) were vectored for landing on the "departure" runway and therefore did not affect the flow of the arriving aircraft. In theory that might have substance but as SIN does not have systems and procedures (that SYD has) in respect of close parallel runway operations then the aircraft on the arrivals runway have to be slowed down to achieve the required approach separation. We did two 180 degree heading changes on long final to achieve the required separation costing us 6 minutes - the worst that I have experienced into SIN was in excess of 30mins which might be acceptable at airports which have large volumes of movements but Changi isn't one of them. I have also experienced being at the holding point on the "departure" runway and having to wait in excess of 10 minutes for SQ aircraft to land (SIN ATC won't give a departure clearance if an arriving aircraft is 2000' or below). If they are not going to use the runways such as 20C for departure and 20R for arrivals then why nominate them as such on the ATIS and in their documented procedures? Compared to the rest of the world their procedures are very conservative and thus makes it easy to for them to look after the government owned carrier.

Earlier this year, I was taxiing in MEL for SIN and the SQ flight was immediately ahead in the taxy sequence for Rwy 16 (duty departure Rwy 27 but because of our weight Rwy 16 was operationally required.) I suspected that the SQ flight would not be "ready" at the holding point so we advised ATC that we could accept a "C" intersection departure. ATC then enquired of SQ whether they would be ready at the holding point Rwy 16. They replied in the affirmative. ATC then cleared them to "line up" and, after a domestic flight departed off Rwy 27, they were cleared for takeoff. Their response was that they were not ready and needed 1 more minute. We had of course followed them to the holding point so the option of the "C" intersection departure was no longer available to us and we had to just wait while SQ took 5 minutes on the runway to be "ready". I was impressed with how polite the ATC personel remained because I know that if the situation was reversed in SIN then ATC would have ordered us to taxy off the runway and then take over an hour to "negotiate" a new ATC clearance.

I understand that we as pilots don't have all the information that ATC has in the arrival sequence but when you have been flying for 12 hours from Europe and know the relative position and altitude of all conflicting traffic on the same and parallel air routes then you know when you are being "shafted". TCAS also gives us further insight as to what is happening during approach sequencing.

I'm not encouraging AUS ATC to do anything to "balance" this problem but simply be aware that this manipulation is going on. GB

3rd Oct 2005, 16:29
common sense/ITCZ......sort of wonder whether you 2 fly and work in the "real" aviation world....I am not familiar with this situation...but let me give you a couple to ponder......KPHX and Southwest Airlines....Pittsburgh KPIT and USAirways.....MMEX,Mexico city and Air Mexicana,KDEN Denver and United Airlines....Minneapolis KMSP and Northwest Airlines...to name a few...Dont tell me there isnt a bias!!! you are wrong,this in most instances is not intentional but still a bias...whats in it for them you ask...how obvious can it be??? These airlines ,at these airports,mostly base airports,pay landing fees etc etc....shorter landing sequences mean shorter fuel burns, da da da da daaaaaaaa......Nobody in their right bloody mind would openly admit to a preferential landing sequence,unless of course an emergency.....I have an ATC mate who will tells me in strict confidence that bias does occur,if you dont believe they do ...you are fools.....My advice to those who get delayed vectors,put out of sequence...GET OVER IT,be the professional you are...or declare the Emergency...you will be on time....possibly even early ;)

5th Oct 2005, 00:59
In response to the gripe about Flow control into Perth, it is simple math: a single runway anywhere other than a GAAP type operation has a landing capacity of around 27 per hour in VMC. If 40 aircraft have ETAs within an hour there are only three basic methods of sequencing, speed control, adjustment of track miles and holding. Often a combination of the three.

Speed adjustments are used to avoid holding and to maintain the minimum required separation standard or wake turbulence standard. Harsh speed reductions close in are usually caused by the aircraft you are following reducing to 120kts at ten to touch. One of our biggest problems is the lack of any standard profile (with the exception of Virgin who seem to fly pretty standard descents). It is not uncommon to have two aircraft same type from the same company on the same track fly vastly different profiles. When the first reduces to 120kts at ten to touch and the second is doing 240kts at the same point and they have been sequenced for the minimum two minutes over the fence, the second is either going to have to reduce rapidly, go round or receive a savage vector. Often when this circumstance occurs the leading aircraft has been requested to make a high speed descent and has not indicated his inability or unwillingness to comply.
I realise it must be frustrating not to be number one and be able to fly whatever profile you feel like on any given day, but the reality is there are more aircraft trying to land than the capacity of the runway. There is nothing in it for ATC to stuff you around, we prefer to get rid of you (in the nicest possible way) as soon as possible and move on to the next problem.
I would encourage any pilots to organise a visit to the TCU and take in the big picture. :ok:

5th Oct 2005, 06:04
rphg_1au....a good post,MyQuestion relates to In-Trail spacing.Is this a 3mile,5mile or 15 mile separation?.This obviously depends on the time of day.Surely below FL100 @250KTS and then a reduction to 170kts at the OM,(for those A/C that can) all aircraft flying that profile would stay in an orderly sequence.Is it not ATC,s job/priorty to make sure that on a first come first serve basis all are treated with the same priority?.I fly into many international airports during peak hours,the controllers dont take any s**t and it is just about always the inabilty of a pilot to maintain a profile thats gets them a re-sequence or a vector.I still maintain in a previous post that there is(on occassion) controller bias.You say"visit your local centre"well I have,and for the most there is no bias,but controllers will tell you the "trouble airlines"we all know they exist and we all know who they are.Radio "attitude"will get your arse in the slinger(guilty as charged)ATC knows this,and they will make you pay,is this bias?bloody oath!!whats in it for them?..a bloody good laugh at the local pisser.I congratulate you on your professional demeaner,but like snowflakes,no two controllers are the same......taunga wakarererangi

5th Oct 2005, 07:54
pakeha-boy The basic rule is two Jets with 12nm spacing at 30 to touch and flying similar profiles will close to 4nm over the fence without any further speed control. If the first slows early and stops like an A330 and the second flies a normal or faster than normal speed, ATC will have to intervene to allow time for the first to vacate the runway (no high speed taxiways in Perth) and the second to land. We also need to get the odd departure away. With Turbo Props 8nm at 30 to touch is the rule of thumb.

We rely on co operation from aircrew to make the whole thing work. Sometimes you're the statue sometimes you're the pigeon, we don't always get it right. :ok:

5th Oct 2005, 15:01
Thanks for the info.Its seems in this particular situation,local runway constraints are the problem.The ability to have several high speed turn-offs,on one runway(in my experience)has made all the difference.I like your analogy,been there,done that.......toparere

6th Oct 2005, 21:21
Also, with these PLTs being passed now, is it better to be a bit early, or on time? Do the arriving aircraft seem to be following the PLT given? If we are aiming to make the PLT, and the TAS has been reduced/increased, does the ADS report you get update this, or do we need to keep you updated, or is the PLT enough? Don, Sydney NOTAM C2059/05 explains (mostly).
The PLT in not a guarantee, The PLT is not an ATC Instruction, Any ATC issued speed overrides the PLT, Pilot must advise ATC when they vary +/- M.01 or 10KT IAS when adjusting because of a PLT.

I have been back for only 5 days from a 2 year hiatus, but the troops think the PLTs have helped, although not every morning has been totally successful (what is?).

7th Oct 2005, 09:53
I'm hearin' ya rphg, it is bluddy embarrasing being associated with some of the Nana types out there ( probably drive to work in the right lane 20ks under the limit and wonder why everyone is giving them the bird ! ), especially when they cant even stick to the ops manual profile which is conservative anyway.

But what is thet answer ? it is so damn frustrating being penalised due to someone elses incompetance.
Its not just jets either, any T/Prop driver will tell you there is no difference between the speed of a jet and them inside 50 miles.........that is of course unless you are stuck behind them.

Maybe we need to do what some busier airports do, maintain a certain speed or get re-sequenced, that might sort them out.

rphg, I would like some of the ATC guys to sit up the front and see how easy it is for us when we get a runway change, and multiple speed changes inside 30 miles ( in IMC )