Transit London/City CTR (again)

[drauk]

flower, I realise that it isn't simple and that a TA from a TCAS could cause some chaos, but I'm not talking about a situation where I'd make that climb just for fun. I realise that they are different controllers too. But, and perhaps AlanM could comment on this, is the entire system really that tight - if so surely they'd be fairly regular problems with inexperienced pilots climbing a few hundred feet in to CAS? Or a dicky altimeter? The wrong QNH? The way you describe it does make it sound as though as soon as you go over 2500 you get hit, directly and without question. Do you see what I mean? I mean, I realise we'd be talking about reduced separation, avoidance moves, delays and god knows what else, but isn't that better than crashing your plane in to a bus stop full of people. All of which makes me think that perhaps the whole transit idea is a bad one. Back to square one!

I'd really like to hear some other opinions on this particular aspect of it.

[flower]

Unfortunately level busts happen throughout the country every week , we get a list of them through the weekly reports , aircraft have to be broken off and repositioned , which at a small unit causes no end of problems but at units such as Heathrow Gatwick etc can cause considerable difficulities.

If you are displaying mode C you should, if wearing an allocated code have been verified, thus we will know if C is working within parameters. If the altitude displayed is within 200ft of that stated it is verified thus you could have in theory just 600ft between aircraft using a 1000ft seperation.

Climb say an extra 500ft , see what im saying.!!!

I believe remembering from my EGLL days that in the area you are talking about that aircraft into EGLL drop not below 4000ft , that could well have changed, so the likelyhood of you hitting something climbing to 3000ft would be low however at certain times (and I said this is going back a few years ) Thames would tell EGLL that they could have 3000ft if they had no traffic to affect.

[Warped Factor]

Barney,

The "standard route" on the western side of the London Zone is via Burnham NDB and Ascot.

Useable irrespective of the runways in use at Heathrow. Not above 1,000ft between Burnham and Ascot to separate from Heathrow traffic, should be able to be a bit higher outside that area.

drauk,

Depending exactly where you choose to pull up you may indeed find yourself reasonably close to something larger. I would suggest you only consider this option if it is good VMC and, during the stress of the moment, you are still able to clear visually the area you are climbing into and whilst up there (albeit probably only briefly) are able to continue looking outside because the larger traffic could be coming at you from any direction and at a significantly higher speed.

I wouldn't say don't do it, I would just say think about it carefully.

Heathrow to a certain extent, and probably Thames more so, don't have a massive chunk of airspace to play with their traffic at the lower levels. One unknown aircraft coming into this airspace can, will and does cause significant disruption.

WF.

[WHBM]

I live about 1nm north of the City tower and notice occasional SE traffic, maybe one or two a weekend, generally due N-S and overflying the tower. However there isn't the frequency there was some years ago.

Lea Valley may be an option north of the Thames but there is no equivalent to continue along south of the river. And if you are going to turn along the Thames you might as well have followed the M25.

From Stapleford I do occasional trips down towards Surrey but always have gone via Dartford Bridge and past Biggin. Anyone feel I'm over-cautious? I don't.

As an aside the BBMF Spits come over from time to time in the summer. Are they exempt from the "Land Clear" rule?

And as another aside about landing clear, when flying over entirely wooded country in Florida my instructor said "Engine failure, put it down on a straight road with no telephone poles. If there isn't one, go for a lake!".

[Fuji Abound]

I have flown this route a number of times. My perception is their are good opportunities to land in the Lea valley area including the reservoirs, but few opportunities south of LCY for a short distance.

I think being realistic whilst their are some green "fields" even at 2400 feet how confident can we be that we could select a suitable field (perhaps at some distance) which on closer examination would be free of people or hazards. If it proves not to be the case other options are likely to be poor.

That said on how many occasions have we found ourselves taking off with few if any options to ensure a safe outcome and for that matter on how many occasions are we below the glide slope on the approach with the result that an engine failure could result in a similiar situation.

It seems to me these factors are all part of the overall risk assessment and it may well be flying the "Lea valley" is pushing the risk to far for some.

On the other hand commercial IFR operation of singles (albeit with turbines) is nearly with us. Now tell me if the aircraft was unlucky enough to have a turbine failure in IMC with a base of say 500 feet whether the pilot(s) would have considered in their overall risk assessment whether or not they could break cloud cover throughout their route and land clear or indeed what chance the controllers would have of vectoring them away from a built up area - and for that matter what about non commercial IFR operations in light singles. How would the CAA react if the outcome was less than ideal and do the "rules" change because we cant see what is below or does the "risk" become any more or any less acceptable?

[AlanM]

Well lots of points there!

Flower, drauk.

The inbound descent profile for westerlies at EGLL is as follows:

Descent from 4000 to 3000 at 13 miles from touchdown 27L/R
Descent from 3000 to 2500 at 11 miles from touchdown 27L/R

Yes, when City airport is closed we normally give Heathrow 3000' if we can. So a climb into the LTMA could get very close to the LHR traffic. As I keep saying, it is all about opinions and, if it goes wrong justification for your actions. If you could get in the RT and tell us what was happening we would then have to phone TC Heathrow and advise them. It wouldn't be instant traffic information and avoiding advice!

The route between Ascot racecourse and BUR NDB is not above 1000 feet SVFR. We will, subject traffic, give you a stepped climb as soon as we can. Especially over the built up areas of Slough/Bracknell.

We operate IFR airways traffic down to 3000' in the Thames RMA - which is DET-BIG-LCY-East to the 2.4/3.4 boundary of the LTMA- DET. We have no choice but to descend to this level. So we are normally just 600 feet above non talking 7000 squawks. Yes, the airspace really is that tight. We get constant TCAS queries from overseas aircraft.....and constant CAS infringers. Daily I see traffic at 2600/2700 feet when the base is 2500' even if only for a few sweeps due to a thermal/lack of ability whatever! The old "inside CAS v outside CAS = seperated" notion is tricky to get your head around!!

People have said here that ATCO's making up there own rules is not the way forward. I agree. However, I still feel I have the right to refuse to issue such a clearance.

Most approach controllers dont allow there IFR/VFR traffic to be at the same level - even though it could be done in Class D with traffic info. Most try to build in a bit of speration. You don't have to - but you do because you feel it is safer. You use your discretion.

Finally then, does anyone ACTUALLY believe that flying between VAUXHALL and LONDON BRIDGES, in a single NOT ABOVE 2000 feet is acceptable??? (MATS pt 2 declared max level - even thought he zone is up to 2500 feet!!)

[FlyingForFun]

Drauk,

You could always try flying level for however long it takes to bleed your speed down to Vg. I doubt that would make very much, if any, difference to the total glide distance compared to the zoom-climb to loose speed, but it will keep you out of the way of airliners, which has to be a good thing.

FFF
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[drauk]

That's a good point FFF. Next time I can I'll do some experiments to see what amount of difference we're talking about. I could also use the other information gleaned here to elect to climb but only up to a max of say 2800' and then stay level. I presumably wouldn't normally have the presence of mind to be so accurate in the event of a serious failure, but after all this discussion and with the mind so keyed up for those few minutes of the flight I reckon I could manage it. Thanks!

[drauk]

Looks like you might be right FFF...

You're at 2000', cruising at 130 but with a best glide of 70. The zoom climb buys you approx. 400', which you get in about 0.2nm. So you're now at 2400', about 0.2nm from where you started and you glide at 70 at a VS of 600'/min. You end up 4.8 miles away. If on the other hand you just slowly raise the nose, pegging the VSI at 0 until the ASI reads 70, you get the best part of 1nm. So now you're gliding at 2000' 1nm from where you started, which you continue to do for about 3.8 miles, thus giving you a total distance of 4.8 miles.

Is this where a glider pilot starts talking about total energy? I suppose with the zoom climb you get to the best glide speed more quickly, but with all the other inaccuracies involved it isn't going to make any difference.

So if the engine were to suddenly quit it looks like you (I) needn't climb and scare anyone above. If the engine sounded like it was about to quit I suppose one could then set 7700, send a mayday and ask for an exceptional climb.

[AlanM]

drauk, mate.

Please don't climb and say I said it was OK!! If there is an aircraft above at 3000, he will probably get a TCAS climb and there may be traffic descending on top of him!

Your calculation shows that there is no need for a climb really. Surely the last thing you should do when you lose your only engine is climb - and risk stalling in all the excitement.

Be safe - there's an urban jungle out there!!!

[drauk]

I'd never have said you said it was okay, but I've taken that bit out just in case!

Thanks.

[sickBocks]

Correct me if I'm wrong but didn't one of the recent GASILs say that the Lea Valley isn't adequate to be considered for 'glide clear' and all that. Answers on a postcard...

sB

[AlanM]

Yes - it is on age 19 of GASIL 2002/03

It didn't say you couldn't fly down the Lea Valley, just that you must be able to alight clear. The full text:

Single Engined aircraft have been seen flying over the built up area of greater London, in the area of the London City Control Zone. While the map shows area which appear to have no major buildings (for example along the river Lee, to the west of the aerodrome), this is still regarded by the courts as being a 'congested area of a town, city or settlement' for the purposes of Rule 5 of the Rules of the Air Regulations 1996. Pilots have been prosecuted and penalised for flying over that area at a height below which would allow the aircraft to alight clear of the area and without danger to persons or property on the surface, in the event of a failure of a power unit, as required by Rule 5(1)(a)(i).

An air traffic controller may give a pilot clearance to fly on a special VFR flight through the control zone. Such a clearance entitles a pilot to disregard Rule 5(1)(a)(ii) (so that he may be below 1500 feet where so instructed by ATC) but not Rule 5(1)(a)(i) (the alight clear requirement). It remians the pilot's responsibility to be able to comply at all times with Rule 5(1)(a)(i) regardless of whether or not he has been issued with a special VFR clearance.

GASIL 03 of 2002 - September 02

Doesn't guide you on whether or not 2400' is high enough to escape!

[drauk]

From 2400' in the average light single you cannot glide clear of the built up area if the Lea Valley, as quoted, "is still regarded as being a congested area of a town, city or settlement". Presumably the same rule would apply to the river. The text quotes Rule 5 as being the need to "alight clear of the area" (not just pick a little spot to land within it) which would rather suggest that the debate is over - you can't do it according to that leaflet. Not quite sure why the leaflet wouldn't go as far as to explicitly say that. Perhaps because if you happened to be in a motor glider you could make it? Any other ideas?

[AlanM]

Case closed matey!?

No more thoughts really - never flown it. Always gone around in the PA28!

For what it's worth, the other ATCO's I work with go around via the QE2.

[Barney_Gumble]

Excellent, this is what PPRuNe is all about. Good debate, fact based and good conclusions.....Barney gonna fly around QE2 bridge from now on. I think I just put a drop more water in my bucket of experience, without losing any from my bucket of luck.

Thanks chaps

[Barney_Gumble]

Apologies for replying directly after my last reply. Bad form so I am told!

BUT

I just re-read the paragraphs from GASIL above and they talk about flying through the LCY and up the Lee River in the context of SVFR stating that under SVFR, as we know, Rule 5(1)(a)(ii) maybe disregarded but not Rule 5(1)(a)(i).

I wonder if this statement and indeed this paragraph was written in response to examples of pilots flying under SVFR in this area at below 1500 feet and assuming they are ok in Law because of the Rule 5 modification when flying under SVFR i.e. they forgot that there is no change to the land clear requirement even under SVFR

Now flying thru the LCY in a SEP at <1500ft is definately

but maybe 2400ft is slightly more even

Just a thought.....doesn't change the general sense of the thread above though.

[FlyingForFun]

And to follow on from Barney's observations:

The GASIL article talks about SVFR through LCY. How often does this happen (question for AlanM maybe?) I thought most transits through that zone were VFR. SVFR, I thought, was mainly used to get through the LHR zone (where VFR is not allowed, because it's Class A).

So how (if at all) are the comments in that article different from what would be expected on a VFR clearance?

FFF
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[Barney_Gumble]

The only difference I can see (apart from >10km vis required) would be that the pilots that the article is specifically aimed at (if indeed it is) maybe are using SVFR in order to fly <1500 ft over the area thinking, in this case incorrectly, that they are safe from the ANO.

It would be interesting to know how many times SVFR clearences are given through LCY.

AlanM......are you out there?

[bookworm]

The only difference I can see (apart from >10km vis required) would be that the pilots that the article is specifically aimed at (if indeed it is) maybe are using SVFR in order to fly <1500 ft over the area thinking, in this case incorrectly, that they are safe from the ANO.

Don't forget, Barney, that the 1500 ft rule also applies to twins under VFR.

It would be interesting to know how many times SVFR clearences are given through LCY.

I have previously asked for and been given a SVFR clearance spefically to allow me to fly below a 1700 ft cloud base over the City of London. The conditions were VMC, but SVFR was necessary because of the 1500 ft rule. Thames was, as always in my experience, very helpful in accommodating my request.