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120.4 13th Nov 2006 22:14

Final approach speeds
 
Without wishing to start a bun fight...

Twice in the last two days I have been forced to reposition traffic already established on the final approach, because the traffic ahead has slowed below its assigned speed.

In both cases the lead aircraft was heavy and if a heavy slows down before instructed it will nearly always lead to a loss of votex separation behind it, which we are legally required to resolve. I recently saw a video of an incident where the poor guy lost separation between two aircraft on base leg because he was trying to sort out a loss of vortex spacing on final, caused by traffic slowing down. The Final Director's r/t is often saturated and we don't have time to be doing this!

I like to think that we are sympathetic to your energy management needs and thankfully, it is quite common now for traffic to advise us early of a specific speed requirement. As a general rule we know that B757s are slow inside 4 and that B773s & MD11s are quick; we know that the A319 is slippery and difficult to slow down but if you cannot deliver the assigned speed you have got to tell us.

Heathrow is operating at the limit and this is all the more reason why you must obey the speeds; capacity depends on it.

Finally, for those who are not yet aware, we now get a mode S readout of your Indicated and Ground speeds. If you cheat, we know it is you and not the other guy. I am sorry to be moaning here but I have had enough of it. Tonight I went into paper work over it and from now on, he who slows down goes-around.:{

Please!

.4

Waldo Pepper 13th Nov 2006 22:51

160 to 4 is always manageable at LHR, when you generally get a long final...180 to 4 can be a problem, but have only been asked for that in Germany.

Just as an aside, my company is pushing for CONF 3 landings on the 320 and 321 as a fuel saving measure...can make for some fast ol' approach speeds with heavy aircraft...I generally advise ATC if it's getting close to 150kts. Limits the potential for embarrassment..;)

matzpenetration 13th Nov 2006 23:01

As a bus operator at LHR you have my sympathy if a/c cannot maintain assigned speed. If certain airlines are frequent culprits just send a letter to the fleet manager highlighting your concerns and the problems this can cause. Most fleets have regular newsletters and bulletins etc... So hopefully the pilots will get a gentle reminder in one of their communications.

Incidentally, as an aside we often struggle to reduce from 180 - 160 in the 319 and are reluctant to increase drag by using gear or spoilers b/c of noise. If this has happened do you have any issues with us dialling in 150kt when the gear comes down (usually at the 6nm mark) as the a/c is still reluctant to slow but it keeps the thrust at idle for longer and lowers the noise footprint? I only suggest this if we can see that we have started to catch the guy in front by struggling to slow down in the early stages of the approach.

NigelOnDraft 14th Nov 2006 05:18

.4 - Problem is our SOPs are already designed around "breaking" your 160 to 14 (1410'?). Gear now goes down latest at 1680', and that will govern when you slow from 160K. Add any "comfort factor" in (as some do) and we are defeating your aim.

Why? The airlines are getting more and more sophisticated software in the QARs, tighter SOPs, and we got more b*llockings in fleet magazines and by phone by not adhering e.g. to stable by 1080' - this needs you to slow to Final Speed, and have the power up - which as you say, can be v difficult in a 319 (since there is so much speed to lose).

A letter to the BA office might help, since there are all sorts of rumours about what is acceptable to comply with "160 to 4" e.g. "there's a 10K tolerance" etc. I am not that happy disregarding an instruction on every occasion, so some clarity / agreement would be welcome!

jondc9 14th Nov 2006 07:08

I know the aviation world is international and as such things are different, when they should be the same.

In the US, Vref+ additive inside the outer marker/FAF is quite normal, especially when IMC.


while I have seen greater speeds, isn't that about standard for you guys. interesting to see that you use a mileage instead of faf.


and the all mighty dollar/pound again with different configurations to save fuel...the marker of landing safety is slow landing speed...oh well.

Mushroom_2 14th Nov 2006 07:10

I hope Air France read this and take note.
Also, why do one airline (BA) have a problem with 160 to 4 and another (bmi) don't?

BOAC 14th Nov 2006 07:34

NOD -

Gear now goes down latest at 1680', and that will govern when you slow from 160K.
- not sure why that affects? Is this some AB thing or a new SOP? At LGW with the 737 I used to take F15 at around 5 miles (obviously with the gear down) and hold the 160 till around 4.2 when drag was available (with slightly early landing flap) to achieve the 'company' SOP. The best I had was a while ago at BRU when they NOTAM'd '160kts to the OM - if you cannot do it you will not land at BRU' - I think that was about 3 miles - and the good old wunderkind BA flt managers did nothing until I said I would be regularly be diverting to the alternate OR breaching SOPs. Then they woke up. :)

As said above, 160 to 4 is not really a problem.

30W 14th Nov 2006 07:55

NOD,

Endorsing BOAC's comments - just because you put the 'Gear Down' doesn't mean you MUST slow below 160kt! Configure as required before 4d except for final landing flap, but MAINTAIN 160kt to 4d. At 4d reduce and complete landing config. With the gear already down, speed will reduce perfectly well to complete a stabilised approach.

120.4

Was it the same Heavy type on both occasions? It may assist by naming the type as contributors may know of something specific to it that may enlighten the reasons for your experience. I don't operate into LL, but agree with an earlier poster. Please send around the offender, not the follower.......


30W

luc 14th Nov 2006 09:41

air france
 
Dear Mushroom 2, I don't know about AF but i am reading it and I happen to fly for AF. What is your problem with AF and final approah speed at LHR???Happy flights.

Roffa 14th Nov 2006 09:41


Originally Posted by NigelOnDraft (Post 2961801)
A letter to the BA office might help, since there are all sorts of rumours about what is acceptable to comply with "160 to 4" e.g. "there's a 10K tolerance" etc. I am not that happy disregarding an instruction on every occasion, so some clarity / agreement would be welcome!

I think the AIP says someing like "must be flown as accurately as possible", there's certainly no 10 knot tolerance as far as we're concerned.

Just as an aside they've changed the rules for 2.5nm spacing and we're now going to be able to do it much more often than we have in the past. There's no tolerance though and in theory if we get to 2.49nm on the approach we've lost separation and should be suspended and investigated.

So, if you chaps and chappesses keep fiddling with the speeds yourselves and separation gets lost on final, don't be surprised if delays build up quickly because there'll be nobody left available to work...we'll all have been withdrawn/suspended!

120.4 14th Nov 2006 09:58

A sincere thanks for responding positively.

The two aircraft involved were both B744, one UK based, the other Far Eastern. The UK based one was indicating 145kts at 6nm from touchdown having been given 160kts to 4. The other was indicating 160kts at 9nm having been given 180kts. (As a rule I always slow from 180kts to 160 kts at 8nm [7nm for medium types] unless there is a very strong headwind, as there was last night.)

Later last night, a B757 who had advised me he would be 122kts inside 4nm was still indicating 190kts at 6nm having been given 180kts shortly after leaving BNN; that is some 20nm after being given the speed instruction! Believing he was going to be slow, I had tucked him up slightly tight behind the preceeding and was then embarrassed to find him 2.5nm behind at +30kts! It reduced to 2nm which is the bare minimum before I am unpplugged by the GS.

The issue here is not the particular speed you need to fly, it is that we must know if you are having difficulty complying promptly. The alternative is that we add .5nm to every gap to protect ourselves and then you will spend much more time going around in circles, burning expensive fuel.

MATZP:
I have only recently become aware of how slippery the 319 is; I now look out for them as a matter of course and give 160kts a little earlier. I also tend to give the B757s 160kts to 5nm and make a spacing allowance for the difference. Would that assist the 319s too?

.4

BOAC 14th Nov 2006 10:08

120.4 - there have been several threads on this topic, including speeds off the hold - 'Search' is a bit slow today so I cannot link to them. However, one of the suggestions was to 'rejig' the ATC parameters and make it '170 to 5' which it was felt would help some of the operators as SOPs tightened up.

sidtheesexist 14th Nov 2006 10:10

The converse is also a problem surely - i.e. AC slowing down TOO late with the result that preceding landing traffic is then put under pressure to expedite it's runway vacation despite having adhered to the speed constraints! I've experienced this on a number of occasions and it strikes me as tho' certain operators seem to figure more prominently in such events.....

Callo 14th Nov 2006 10:16

Speed control
 
120.4 I think I may have been on finals when this incident happened. The heavy had slowed early and the A/C behind was a 319 which as you said can be difficult to slow down. I overhead you tell them they were doing 180kts to which they replied "we're trying" . As the heavy was mainly at fault why did the tower controller make a smart comment upon landing and roll out to A-10 (A/C behind still 700' agl) "are you having speed control problems" to the 319? Controllers concern is always appreciated but this appeared to be somewhat of a smarmy comment.

Of course runway occupancy should be kept minimal but good SA is also paramount to operations. There isn't always a need to vacate at A9 or earlier so why imply the AC should have vacated earlier. 700' agl leaves plenty of time. By rolling to A10 brake wear is reduced and passenger discomfort is kept to minimum. I hope I have got the wrong end of the stick as Heathrow controllers are always professional and don't resort to being facetious or condescending. If the controller was annoyed then he should have said so. Aside from this keep up the good work.:D

120.4 14th Nov 2006 10:24

Thanks BOAC

I do remember something about that a number of years ago but it seemed to die a death. As I remember, it was principally aimed at reducing the effect of strong wind conditions on the landing rate. It seems to me the touble might then be that the types that are typically slow once de-restricted may then be slower for longer and as the traffic behind would then be 170kts for longer it may lead to greater catch-up.

I don't feel qualified to give an opinion really but if you feel that it is worth looking at then can it be raised through some mechanism and let's trial it? I know a gentleman (CM) who has done a lot of work with NATS' staff on the mathematics of final approach spacing and speeds.

As Porco has correctly pointed out, with the rule changes for 2.5nm spacing, we cannot leave speed fluctuations unchallenged as they will quickly drop us in the doodoo. And I promise you, the first time somebody does it to me will be the last time; I will flat refuse to do anything less than 3nm.

.4

Bearcat 14th Nov 2006 10:31


Originally Posted by matzpenetration (Post 2961577)
Incidentally, as an aside we often struggle to reduce from 180 - 160 in the 319 and are reluctant to increase drag by using gear or spoilers b/c of noise.


which is more important?....using speed brake to slow for 180 to 160 with insignif noise consequences....or do nothing and grimice and watch the speed painstakingly slow to 160....by that time your at 4 miles......(sometimes even the gear is used if I am high on the CDA) Think about it.

when LHR say slow to 220, 180, 160 what ever.....i proactively do it cause I am keeping my space in the sequence and looking after no.1

120.4 14th Nov 2006 10:35

Hi Callo

I'm not sure if it was the same incident. The Tower ATCO involved with the UK based B744 is known for his willingness to speak his mind and I do understand his frustration. If we present less than vortex minimums to the Tower ATCO then we are effectly handing him an illegal situation and he is quite within his rights to send the unseparated (cos that's what it is) traffic around.

I'm sure most try to be professional about it but it can be very difficult to hold your tongue. I confess that in the case of the Far Eastern gentleman, I said to him, "Capacity at Heathrow depends on you flying the speeds, Call tower 118.7". I felt a bit bad afterwards, but I hope he understood my point. Anyhow, his ops. section is about to get a letter from NATS about it and I am sure he will understand then!

.4

IcePack 14th Nov 2006 10:46

Bit of tail waging the dog here.
Not all pilots are of the same caliber.
If a pilot feels safer slowing down as per company SOP's then so be it flight safety is paramount.
Only excuse to not telling ATC is because you can't get a word in edgways.:)

Gary Lager 14th Nov 2006 10:49


Originally Posted by matzpenetration (Post 2961577)
if we can see that we have started to catch the guy in front

Too many people flying around think the TCAS TFC display gives them the necessary information and/or authority to disregard ATC instructions.

Not suggesting you do, matz, but you did sort of bring it to mind. I get very unhappy when chaps I fly with say things like "ooh look we're getting a bit close to the guy in front I'll just slow down a bit", without asking/telling ATC. Admittedly, none have had experience in the LTMA yet but I think this influence of the TFC display has a negative impact on the ATC/pilot 'team' aspect of ops.

I'm sorry it's hassle for you guys in ATC, but please do file that paperwork if you have a problem. In most progressive companies, criticism of this type will be acted on constructively. You may think you're doing us a favour by keeping offically quiet, but that's probably only at the expense of the next group of guys to experience the same problem - maybe with a less successful outcome.

It also avoids the 'no-ones complained so it must be OK' excuse beloved of airline/NATS management.

Callo 14th Nov 2006 10:57

120.4 as I said I think you guys do a great job in what is easily one of the most challenging airports in the world. I also understand how frustrating it can be when people only half heartedly comply with instructions.

I don't blame the controller at all for venting his anger but I wonder if it was a case of mistaken identity. Who had caused the problem? Also why not just say "do you understand the effect you have by not complying" etc instead of smart, condescending messages. We're a simple bunch who don't like mixed messages. Its just a minor point in what is otherwise a top class operation. (controllers not Heathrow)


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