BNN VOR - Which Routes?

[steve1969]

Can anyone out there tell me which routes into LHR are generally put into the BNN hold?

Am I right in thinking they generally include transatlantic traffic?

[Lunar Landing]

I live on the western part of the OCK hold...and I see, and listen to on my scanner, American and United flights...so i can factually say that not ALL tranatlantic flights go to BNN. On that note, Air canada i have not heard at OCK...

Smooth skies,
Dan

[Max Angle]

Basically anything coming from the North of LHR will end up at Bovingdon. Transatlantic traffic depends a bit on which NAT tracks are in use and which one the a/c has used for it's crossing. Sometimes when things are very busy I have been sent to the OCK hold when coming from the North.

[steve1969]

Thanks for that MAx and Lunar.

Bovingdon does seem to be a very busy hold. I have often seen a/c doing 3 or 4 circuits before leaving the pattern. It doesn't surprise me that a/c are sometimes sent via OCK.

Thanks again.

[Lunar Landing]

I think that BNN is used for 27R/09L missed approaches although im not sure on that. Could someone clarify?

Smooth skies,
Dan

[Gonzo]

BNN is the hold for anything coming from Scotland, Northern Ireland and rest of the UK, and anything that has come 'Northabout' over the Atlantic, ie. Canada, W. USA etc.

The Missed Approaches don't use any of the four inbound holds, if neccessary or if radio fail, go arounds can hold over CHT (Chiltern) or EPM (Epsom) at 3000.

Gonzo.

[Lunar Landing]

Always wondered that...thanks for the clarification. Gonzo...did you recieve my email?

One other question regarding holds...when the pilot is inbound on HIS GPS route or whatever, is he aware of what hold to go to, before being informed i mean?

Smooth skies,
Dan :)

[Fright Level]

The IFR flight plan has the arrival from the airways system to the runway via the final fix on the airway and beginning of the STAR. For LHR, that is LAM, BNN, BIG and OCK depending on which airway you were on to get to the UK. The stacks can hold much more than 3 a/c, but usually a busy day might see 6-8 in the hold. Aircraft are descended in the hold, so while they appear to go round, they also go down and then feed off the bottom onto the arrival (usually by radar vectors). Not unusual to be directed to another hold if "yours" is full.

Rod

[5milesbaby]

Air Canada can be heard at OCK, just depends on the tracks being used over the Ocean. I would say that OCK is used more than BNN, as all the oceanic flights coming through the Bristol/Berryhead sectors normally go to OCK, and they are only quiet on a VERY northabout day. When tracks are hovering around 55N or further south, it must be about 50/50 or greater through OCK.

On a side note of busy stacks, try out LAM on the mid afternoon/early evening rush from Clacton sector. Stack swap city from where I watch.

Flying Togs, if you don't know, holding patterns are set things; basically from over the fix, a left or right turn 180degs (outbound turn), outbound leg, inbound turn 180degs again, inbound leg. For LHR, each leg of the race track has to be 1 min long, therefore each complete hold taking 4 mins. I've seen recently delays up to 30 mins so its possible to do 7-8 patterns, but I know lenghtier delays have happenned. Approach use these timings to plan when to bring an a/c off to commence approach, so as to get just the right number packed in. Orbits (or spins) are also used to get a 2 min hold only, to aid this timing.

-----ignore the waffle, its getting late in the bottle (hic)-----

[steve1969]

Thanks for that 5milesbaby. I wasn't aware of the timing set for each leg of the hold.

Maybe you can answer another point I'm unclear on: What's the procedure for a/c joining the hold? I've seen what appears to be a/c coming in "from the side", as it were.
A/c 1 is flying the hold pattern, commencing its turn over the fix while a/c 2 is approaching from a/c 1's 4 o'clock. They sometimes look as though they may be coming into conflict. It often looks pretty tight for space!

Grateful for your thoughts.

[eyeinthesky]

Hold axes are usually arranged where possible so that traffic on a particular route can enter the hold directly. But they must also not conflict with other holds so sometimes they have to be angled differently.

The BNN hold is aligned so that traffic on a normal route into it (which comes from Westcott radio beacon to the NW) can enter directly. This is probably what you are seeing, although sometimes traffic is routed direct to BNN and may approach at a slightly different angle.

Where there is more than one route into a hold, such as OCK, then someone won't be able to enter it directly. In the case of OCK, traffic from the South West can enter directly, but traffic from the West must fly over the beacon and then turn right back towards it to enter the hold.

This is a layman's description of the holding process. If you want a detailed explanation of the Direct, Offset and Parallel entries to holds, then let us know!!

[5milesbaby]

and never worry (too much anyway) about them being seperated. All a/c in are seperated by 1000ft, the minimum, and rules state that an a/c descending to a level previously occupied can only do so when the other is LEVEL at the lower level (ie 2000ft below). This is different from normal climbs/descends as we can re-allocate a level when another a/c has passed it by 400ft or 200ft, depending on wether the a/c left or just passed through the level.

Any a/c entering the hold will again be at different levels too, normally level at the FL and again just descended down on top of the one below.

The holding patterns can be found on the net somewhere giving all the rules for each particular hold (ie how long each leg is, some are 1 1/2 mins. also how the hold is aligned as said above) and are taken from the UK Air Pilot. I'm sure someone here can post a link.........

[Warped Factor]

5milesbaby,

and never worry (too much anyway) about them being seperated. All a/c in are seperated by 1000ft, the minimum, and rules state that an a/c descending to a level previously occupied can only do so when the other is LEVEL at the lower level (ie 2000ft below). This is different from normal climbs/descends as we can re-allocate a level when another a/c has passed it by 400ft or 200ft, depending on wether the a/c left or just passed through the level.

We use the standard separation rules for allocating levels in the holds at Heathrow.

That is a level may be used by the traffic above it after a level vacated report from the pilot who is leaving the lower level or, assuming no clutter/garbling, seeing -400ft and increasing on the Mode C of the traffic leaving the level.

We don't wait for a 2,000ft gap, unless the rules have changed in the last few days while I've been on days off.

WF.

[ 26 November 2001: Message edited by: Warped Factor ]

[5milesbaby]

Thanks WF, I thought a while back the rules had changed after several SMF and TCAS alerts caused chaos one afternoon, leaving a severely short watch due to form filling and radar replays. Obviously the LATCC chinese whispers fully operational again :p

[steve1969]

Thanks for that all of you. I am a lot clearer now on what is going on within the hold.

I've been looking at the BNN STARs (AD 2-EGLL-7-2) and I guess you mean that direct entry to the hold is on a heading of 121.

Another thing - do ATCOs clear a/c to leave the hold on a particular heading (depending on whether easteries or westerlies are in force) or to another VOR? And how long do a/c generally have left to run after leaving the hold?

[eyeinthesky]

Unless the radar is broken, they ALWAYS leave the holds around LL and KK on a radar heading. This is dependent upon the runway direction (easterly or westerly), the wind, and other traffic that the controller may have. There is in fact not much variation in the headings for a given runway direction, as the aircraft have to remain in the relevant Radar Manoeuvring Area (RMA) to provide separation against departing traffic. They will be radar vectored to intercept the ILS. During this process they will talk to two controllers: The Intermediate Director who takes them off the stack and puts them into a downwind sort of position: and the Final Director who turns them onto the ILS at the required gap from the traffic in front. Once they are fully established and at about 10 miles from touchdown they will be transferred to the tower for landing clearance.