Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

Final approach speeds

Tech Log The very best in practical technical discussion on the web

Final approach speeds

Old 14th Nov 2006, 16:49
  #41 (permalink)  
 
Join Date: Jan 2001
Location: home
Posts: 1,343
There seems to be two issues here. One regards the crews who are slowing slightly before 4nm to be stable at 1000' AGL. The other regards the crews who slow down miles before they should without advising ATC. The latter crews seem to be the problem. Personally in the London TMA even if I am given no speed control I will advise ATC of any significant change of speed. For the former issue I've worked out some figures on the back of a fag packet. An aircraft starting to decelerate 0.5nm early the aircraft will arrive at the runway 2 secs later will effectively be 100m further back and 20 ft higher. IMVHO this does not seem to be enough to really effect separation.
Right Way Up is offline  
Old 14th Nov 2006, 16:49
  #42 (permalink)  
 
Join Date: Jan 2001
Location: UK
Posts: 2,045
CM
Are you sure about that NoD? I flew the 319 for 5 years (perhaps including a tour with you) and 160 to 4 is achievable unless you are very light (in which case I always mentioned the Vapp to Director). It requires flap 3 and the gear down with the power up then a judicious timing of the managed speed selection at somewhere between 4.5 - 4d so that the engines go to idle and you cross 4d with the speed at 160kts but the green arrow pointing down. Granted this was tricky when the engines had to be at power at 1000ft but once that requirement was removed and idle power at 1000ft was permissible it became a doddle.
Don't know what "rules" (FCOs) you have? But I see no removal of the requirement to have Approach power set at 1000' Also, tail wagging dog again - so to comply with ATC's requirements you purposefully bung all the drag out early (F3, gear) so creating noise and wasting fuel. We now have a gear down ~1600' at 160K procedure for noise / fuel, and one should take flap when one "needs to" (approaching min speed for flap), not using Flaps as Drag
However, some other designs clearly are not so versatile, SO it is up to ATC to make accomodations
It is not the "design" that is the problem.... it is the paranoid attitude of the Airline Managers about everthing being absolutely sorted prior 1000', and having the tools to pursue you when you are not

We can all devise clever "tricks", some amounting to poor airmanship / fuel wasting / noisy, and "just crack" the 160 to 4D and 1000' stable. We are not talking about "clever pilots" on a "good day". We are talking SOPs, for all pilots, on all days. 160K to 4D and truly stable by 1000' are, IMHO, incompatible - hence the thread. One will have to give....
NigelOnDraft is offline  
Old 14th Nov 2006, 17:11
  #43 (permalink)  
 
Join Date: Aug 2003
Location: UK
Posts: 88
Without wanting to tell anyone how to suck eggs, give this a go, even in a very light ac-
On 319 160 Conf2, at 4.4nm push managed, gear down conf 3 conf Full. You will cross 4d within a couple of knots of 160, but crucially thrust idle. Fully stable at 1000agl. Variables in ambient conditions will have to be considered when pushing managed (tailwind, high temp etc). Bottom line is dont let thrust spool up within 5 nm i.e. putting gear down with speed selected 160 which has the effect as far as I'm concerned of destabilising the approach!.
I've found it best to include this in my brief, otherwise p2 gets a spasm in their left hand
lamina is offline  
Old 14th Nov 2006, 17:17
  #44 (permalink)  
 
Join Date: Dec 2004
Location: France
Posts: 6
Heavy aircraft high speeds

There are plenty of occasions before becoming established when you are able to advise of your operational requirements. Tag it onto the end of a readback.

Flying a 744 with a landing wt of 302.0 tonnes means a Vref of 158kts and a Vvat of 163 min or as much as 170kts. Makes 160 to 4nm and then slow down hard to do so we just tell the ATC bods nice and early and they are as pleased as punch at a bit of prior warning. Also I always nominate the turn off I expect to take so as to make their job a bit easier. It's a two thing you know and NO excuse for not knowing or being able to let them know. It was all talked about in the briefing so let ATC know asap.
rocketfun is offline  
Old 14th Nov 2006, 17:26
  #45 (permalink)  
 
Join Date: Apr 1999
Location: UK
Posts: 1,691
Originally Posted by NigelOnDraft View Post
CM Don't know what "rules" (FCOs) you have? But I see no removal of the requirement to have Approach power set at 1000' Also, tail wagging dog again - so to comply with ATC's requirements you purposefully bung all the drag out early (F3, gear) so creating noise and wasting fuel. We now have a gear down ~1600' at 160K procedure for noise / fuel, and one should take flap when one "needs to" (approaching min speed for flap), not using Flaps as Drag
Nige - not sure where it'll be quoted now (no longer on the fleet) but the removal of the 1000 approach power set requirement on the 'bus was made by FCN several years ago specifically in response to the inability of the A319 to achieve the 160 to 4 requirement and approach power at 1000. I believe DW may have been the author of said FCN. Maybe its slipped from common knowledge but the rules defintely changed, in no small part due to agitation from those of us who'd been flying the minibus since it arrived in BA. I don't see a problem in using a high drag approach to comply with ATCs requirements at LHR. We fly the aircraft suboptimally all the time, with controlled rate of descents instead of dirty dives near MSA, slowing down and dirtying up early only to find we're being dragged in low and slow (FRA springs to mind) and all manner of other scenarios. We do it because it's in our corporate interests to make LHR work, and if you ask the managers if they'd prefer to save a splash of fuel at the expense of reducing the landing rate at LHR I think I know what the answer will be.
Carnage Matey! is offline  
Old 14th Nov 2006, 17:47
  #46 (permalink)  

Controversial, moi?
 
Join Date: Oct 2000
Location: UK
Posts: 1,546
Why can BA not make an exception at LHR where we have a lower height at which we must be fully configured and stabilised. The reason for the slightly conservative BA numbers was/is to keep a firm grip on the avoidance of rushed or high energy approaches.

At LHR due to the clockwork precision and consistency of the controlling this is never an issue. Therefore an exception could be safely accommodated.

I notice that the 411a has to add his standard (and tedious) format comments which seem rich coming from a resident of a country where I have experienced more cockeyed, uncoordinated, impossible to achieve and sometimes downright dangerous ATC controlled approaches than possibly anywhere else in the world.
M.Mouse is offline  
Old 14th Nov 2006, 17:51
  #47 (permalink)  
 
Join Date: Jan 2001
Location: UK
Posts: 2,045
MM... oh come on BA Mgmt and commonsense in the same sentance... whatever next
NigelOnDraft is offline  
Old 14th Nov 2006, 18:46
  #48 (permalink)  
Thread Starter
 
Join Date: Mar 2002
Location: LONDON
Posts: 314
411a

I am not known for rising to the bait on these forums but, by golly, you are driving me close. You are absolutely right... That is the whole point of the thread: I cannot do my job properly (which is to safely squeeze every ounce out of Heathrow's miserley two runway infrastructure) when air-crew do not fly the instructed speeds or advise me if they are not able to.

Please note: I am not critizising aircrew for not being able to fly the speeds but rather for telling that they will and then not doing it. That action puts me outside the law and is in danger of getting me suspended when I am already operating at minimum spacing. If the SOPs are no longer up to air-crew requirements then we must change the SOPs and accept the loss in capacity.

We operate ATC at Heathrow with a pen and the Mark 1 eyeball. We have no tools to help us. Could YOU judge when to slow down to give exactly a 2.5nm gap, when the lead aircraft in any pair crosses 4DME, with a 30kt crosswind so that one is seeing a tailwind and the other a headwind at the point they turn in, when one aircraft is a slow B757 and the other a fast A319 ... WHEN THE AIR CREW WON'T FLY THE SPEED YOU GIVE THEM ANYWAY??? AND KNOWING THAT IF YOU GET IT 0.1NM TIGHT YOU ARE ANSWEREING TO SRG?



There, I 've don it, I have finally lost my rag over this.

By the way, the UK AIP is clear, there is NO tolerance on final approach speeds - they must be flown as accurately as possible.

Sorry

.4
120.4 is offline  
Old 14th Nov 2006, 19:19
  #49 (permalink)  
 
Join Date: Dec 2005
Location: USA
Posts: 563
dear 120.4


you have really started something here and I think it is a good thing.

While I have never been to England, certainly KORD must qualify as a busy airport with demanding speed control.

I was flying as copilot to a complete arse of a captain. we were told to do 160 knots to a certain point and we acknowledged same...

the captain slowed to 145 knots and boy was ATC yelling.

threats to take us off the final etc.


I asked the captain why he didn't speed up...he said: I am stable now and don't plan to change my power setting.

There are actually pilots who believe they must not touch the throttles once stable...more power, faster, yes you might have to retrim and put the nose down a bit to keep the glide slope.

Part of this is training. I had a checkout one time in a piper, I was the instructor and had another CFI getting checked out to fly a T tail turbo lance. He asked me what power setting to use on final...I told him it changes with conditions, mainly wind, but why not start with about 17inchess of MAP.

there we were on final, getting lower and lower on the GS and I asked him what he planned to do (again, this chap had a cfi commercial instrument)...HE told me that I WAS WRONG AND THAT 17 inches of MAP would not hold the glide slope ( very high winds down the runway).

I was in shock...here was someone who didn't know enough to add power...this chap is now a captain for a major airline.

DEAR 120.4...sometimes pilots are simply not familiar enough to be too precise with planes...modern airliners of course have a great amount of automation which should allow people to fly within 1 knot of assigned speed...but

is it clarification? is it something you say in your clearance? maybe say...maintain 160 knots to 3 mile final and NOT ONE KNOT LESS till then.

emphasis mine

I will take flack for this, but there are some marginal pilots out there...others are quite good but stubborn about bumping up the throttles...FUEL EFFICENY don't you know.

And some controllers just accept as fact that planes are slippery etc. well, they can all pretty much do 160 knots on final...but some pilots won't want to use more flaps etc.

I wish you luck and perhaps an all users meeting with pilots and controllers might help.

And yes, that 737 flap/rudder stuff did muck things up a bit...so put out more flaps and gear and yes you might have to add power just like my checkout student was so reluctant to do.


good luck

jon
jondc9 is offline  
Old 14th Nov 2006, 19:51
  #50 (permalink)  
 
Join Date: Dec 2003
Location: Tring, UK
Posts: 1,402
120.4: I feel your pain!

I'm going to stick my neck out and say that under normal circumstances, i.e. no tailwind, icing, etc. I can't see why any aircraft shouldn't follow the 220/180/160 regime on approach to LHR, if they use all the aerodynamic devices available to them. If they genuinely are not able (Vat>160, for instance) then they should inform ATC at the earliest opportunity.

As BOAC says, 160 to 5 isn't going to make a significant difference but 160 instead of 180 for several miles is.

If I was doing an instrument rating and didn't fly ATC instructed speeds, I would fail - simple as that. What's the problem in real life? (Quickly dons fireproof jacket )
FullWings is offline  
Old 14th Nov 2006, 20:12
  #51 (permalink)  
 
Join Date: Jan 2001
Location: Deepest darkest Inbredland....
Posts: 543
Reading this thread is very interesting. Having it based on LL is good but it can (and should) be widened to all airports where AC are given speeds to fly. At a certain airport to the north of London some operators are well known for not flying the correct speed. They are asked for what speed they are flying and the reply is usually "coming back to 160 'til 4" so you ask what is your speed now? and then you are told 180.

WHY???

You know that they have been told a speed to fly but they seem to think it is optional, when it is an instruction like any other. If you can't fly it, tell everyone, and it will be accommodated but blatantly ignoring it causes much more workload to everyone including that AC. Basically I think that MORs are going to be filed before anything changes, but as stated before that is my break used up before I return to the fray.

These speeds are for everyone's benefit so lying and not complying really isn't a good idea. Please try and comply and if not tell us.

Thank you to all the pilots who help us make this crazy system work.
terrain safe is offline  
Old 14th Nov 2006, 20:13
  #52 (permalink)  
 
Join Date: Nov 2003
Location: London
Posts: 85
120.4 and others ... sorry if I am talking out of the back of my hat, but I couldn't help noticing the coincidence of ATC experiencing problems with unexpectedly slow aircraft last night and the (moved) post about mountain waves in the London area also last night (which apparently can have the effect of slowing down aircraft TMG unexpectedly). Could the two be linked?

On the general question of pushing tin to the limits, I have to say I am uncomfortable with any NATS management culture that has allowed commercial pressure to have any place uppermost in a controller's mind whilst operating. And I am not sure I like the idea of some controllers standing up and saying enough is enough and many others not doing the same. Where is the self-regulation above individual level?

Using a mark one eyeball and a pen to run the Heathrow show in 2006 is a scarey enough thought without suggestion that hairy concepts like "ATC is expected to manage separations to optimise airline fuel savings" are in play.

I am also slightly surprised at how many pilots might still be learning how to stay in front of their type, but it's heartening to see some well-positioned gurus able to point the way
late developer is offline  
Old 14th Nov 2006, 20:47
  #53 (permalink)  
Plumbum Pendular
 
Join Date: Aug 1999
Location: Avionics Bay
Age: 50
Posts: 1,119
I am totally amazed that so many of you (pilots) can not manage 160 to 4 under normal circumstances.

It may not be so eco friendly or quiet, but if that is what ATC ask you to do then it is not rocket science to do it.

Do management really give you a hard time if you have to drop the gear a mile early? I don't think so, and if they do just say that you had to in order to comply with ATC speed requirements.

411A, your comments show that you have no understading of the current industry. The skies are WAY too crowded for the prima donna pilot who will "only fly the speed I want to fly" just through sheer obstinance.
fmgc is offline  
Old 14th Nov 2006, 21:09
  #54 (permalink)  
 
Join Date: Jun 1997
Location: 5530N
Posts: 845
yawn o friggin brawna....if you cant comply frig off else where....what a bunch of wooozies even on your 744s. If your vref is is 164...tell em at OCK...BNN ...LAM wherever...they'll accom you....there paid to....they dont guard the gates of heaven....they are normal folk and their remit is to cram....

Talk to them......they'll talk to you....piss them off ..they'll eat you...talk early to sort you.

Just like NY.


Ze Bear
Bearcat is offline  
Old 14th Nov 2006, 22:21
  #55 (permalink)  
Anotherflapoperator
Guest
 
Posts: n/a
I think the gist of 411A's comments were that he was glad he flew a type that had good healthy performance at slow speed and not one of the modern types being moaned about.

That airport North of London, hmm. I can understand the attitude of some pilots, I know the approach is operated by West Drayton, and that the controllers on duty may work other approach duties too, but giving 160 to 4 then handing over to tower who clears you to land right away tends to make a mockery compared to KK for example, (my other daily grind) where I stick rigidly to the speeds given and you can see the traffic departing and lining up long after I pass 4 miles DME.

Like 411A, my olde worlde 146 is more than able to fly 160 to 4 easily at whatever weight, but since we were assimilated by the Borg the management have also made us do this at Flap18 gear down, when we always came into LL with flap24 and gear up until 4 miles. Unstable? B00ll0cks is it.

Anyway, thanks Willie for kicking us out, we'll soon be able to fly 250 below 10K again! Yippee! Can't wait.

That fancy Mode s, good innit? 120.4, do you get anything useful like that from 146 squawks or just the basic stuff downlinked?
 
Old 14th Nov 2006, 22:23
  #56 (permalink)  
 
Join Date: Jun 1999
Location: Lost
Posts: 330
Slightly Off-topic: With tighter spacing I find intensely annoying when someone checks in on Tower with their life story just as you're passing 280' and the bloke ahead has just cleared and Tower are about to give you landing clearance. How about callsign only with Tower as well?

And get bloody Beeline to learn to talk short and sharp.

Also: When we exit why don't Tower tell us to take A or B taxiway*? At least we can keep rolling that way and clear the runway proper like.

(*- Apologies to theose perverts who turn Left off 27L)

Hmm - letter to Chirp on the way I think.
Dunhovrin is offline  
Old 14th Nov 2006, 22:38
  #57 (permalink)  
ok1
 
Join Date: Oct 2005
Location: Morgantown, WV
Posts: 22
A little more off-topic:
Just wondering if it'd help in any way to squawk Vref from the FMC on the next generation of transponders. That could give you some idea of the deceleration from 180/160 as well. Or there's already too much stuff on the labels?
ok1 is offline  
Old 14th Nov 2006, 22:39
  #58 (permalink)  
Thread Starter
 
Join Date: Mar 2002
Location: LONDON
Posts: 314
Flapo

Nothing like that off the 146 I 'm afraid, I'm pretty sure they are all elementary Mode S only. But then again quite a number of the Buses are as well.


.4
120.4 is offline  
Old 14th Nov 2006, 22:53
  #59 (permalink)  
Thread Starter
 
Join Date: Mar 2002
Location: LONDON
Posts: 314
OK1

Yes, it may well do. I don't think we would use it directly but aim to incorporate it into ATC tooling. If we had a useable final director support tool it would ideally advise ATC when to slow each aircraft to their preferred final approach speed so that it would cross 4DME at the optimum spacing for its weight.

In the case of a B773 (fast) following a B757 (slow) we would then know when to slow the former to achieve optimum runway performance with minimal risk of a go-around. I believe that 26 parameters are downlinked at the moment but I don't know if Vref is one of them. (I often ask, especailly from B757s.) Anybody else know?

Only any good of course if all air-crew deliver it.

May I take this moment to say that on the majority of occasions when you select the Mode S IAS you do see a line of 160s going down the approach, certainly within 1 or 2 kts.... but it only takes one to get suspended.

.4
120.4 is offline  
Old 14th Nov 2006, 22:55
  #60 (permalink)  
 
Join Date: Dec 1999
Location: LHR/EGLL
Age: 40
Posts: 4,311
Anotherflapoperator:

The benefit to Tower of you doing 160 to 4 even if it's quiet is that it's standard, and Tower knows you'll be coming down at 160 to 4. Thus he doesn't have to co-ordinate either 'standard' speeds or 'own' speeds for every inbound individually. It helps to know in case he gets one departure he might be able to squeeze away. Far easier to judge when he knows what speeds you'll be flying down the approach.

Dunhovrin:
Also: When we exit why don't Tower tell us to take A or B taxiway*? At least we can keep rolling that way and clear the runway proper like.
Because there is no way Arrivals could co-ordinate every single inbound with GMC. When it's going ape, even GMC doesn't know which way you'll be going until he's on the R/T to you. Yes, we try and sort it out if it's a possible go-around, or if there'll be a gridlock if you come off at one particular exit, but Arrivals just doesn't have the picture of what's going on in GMC to decide. And personally, as GMC, I'd look unkindly on someone deciding where my a/c were going for me. If you can't get in on the R/T, move fully off the runway onto A, but then stop and keep your options open. I was stitched up big time the other day by an A319 coming off short from 27R, turning left on A without talking to me, abeam a company push from stand 101. What he hadn't seen was a Cathay 747 being towed towards him. I had to get the 747 to reverse back. Lucky he was being towed!
Gonzo is offline  

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.