EGLL Dover Departures

[Thunderbug]

Spent the last few days doing Dover departures out of Heathrow. Each departure was subject to Start-up delays as well as long times spent on taxiways awaiting departure.

The controller mentioned 3 minute spacing and at one point it was raised to 4 minute spacing.

What are the issues here? Why does this departure seem more prone to disruption than others.

Just curious..........


T'bug

[thinkofdolphins]

MDI's sounds a likely cause. A frequently used ATFM tool to avoid a regulation and the associated NATS attributable delays. Dover sector is a narrow piece of airspace being fed by not just LL deps but GW,SS,KK,LC etc. plus traffic inbound to Brussels TMA dropping through London TMA climbers. MDI's and ADI's are not overly popular with tower controllers as it increases their (already busy) workload and as you experienced, extra time fo a/c sitting on the ground.
But as I wasn't there this is just an educated guess to aid your query

[Vlad the Impaler]

From my dim and distant memory of such things Dover's on Westerlies have a standard 3 min between them due to the raking left turn after departure. There are so many interpretations of this turn that 2 minutes can sometimes put consecutive Dovers embarrasingly close together if the second one is a bit quicker and a bit tighter in the turn. The classic used to be an A340 followed by a 747. The A340 gets airborne and used to be told "no atc speed restriction" at which point they would gleefully come back to 210kts and be eaten alive by the Jumbo 2 minutes (that is a tower 2 minutes which in my experience is somewhere between 61 and 80 seconds) behind. Anything longer than 3 minutes is indeed to due flow regulation which could be due to a number of things. The most likely cause is simply too much traffic forecast in the DVR sector at the same time but it could be due to Weather or there is also an enormous danger area owned by the belgians (they use it for exercises in their attack gliders) I think which can have some severe restrictions on the use of the old greenway.

[expediteoff]

Hey Thunderbug.
The word I hear round my way is that those 3/4 minute MDI's (Minimum Departure Intervals) are gonna have a bit less of the "Minimum" part applied, thanks to the encouraging forthcoming conditions about to be provided by the employer.

So I'd get used to sitting on stand a bit longer and eating biscuits!

[anotherthing]

The classic used to be an A340 followed by a 747. The A340 gets airborne and used to be told "no atc speed restriction" at which point they would gleefully come back to 210kts and be eaten alive by the Jumbo 2 minutes

Not quite correct Vlad. The A340 would get airborne and fly at 210/220Kts as was their right (the no speed restriction is a removal of the 'not above 250kts below FL100').

It was the subsequent taking off of the speed restriction on the aircraft behind (76/74 etc) that caused the problems!

It also didn't help that the bus drivers didn't inform the ATCO of the fact they would not be climbing at 250Kts, this was remedied when controllers were quickly brought up to speed with the facts of the A340 climb characteristics (basically, crap)

[BravoMike]

Hi,

Can be a lot...

If you PM or post the CALLSIGN i'll see what I can find (+ day and approx hour)
Could be restrictions into MAASTRICHT AIRSPACE or EBBU WEST(KOKSY sector)...
Let me know and I'll try to find out ...

grtz

[beaver liquor]

DVR deps from the TMA airfields funnel through a narrow piece of airspace, made worse a lot recently by CB156 French military use of airspace that infringes the airway.

Sensible tactical use of an MDI can avoid the need for a flow regulation by delaying a small number of departures, rather than giving everyone flying into the sector a CFMU slot delay. Less overall delay is a good thing, no?

Edited due to reply appearing grumpier than intended. Apologies.

[ImnotanERIC]

thats a bit of a !!!!ty response to his comment. i don't see where he wrote something you might take offence to?
you are not an ojti that cries are you?

[Thunderbug]

Thanks for the replies - although Expediteoff's response was a bit too subtle for me, but doesn't sound good....!

For info: Ops were Easterly throughout the period (don't know if that makes a different). As for MDIs being better than slots - Not sure. It was 53 mins from calling ready to getting airborne. At least with a slot there is a chance of an improvement.

T'Bug

[anotherthing]

Thunderbug

...response was a bit too subtle for me, but doesn't sound good....!

We are currently fighting the big possibility of a major change in our pension benefits - and there are also rumours that the management want a pay freeze for Jan 2009 - Jan 2010 as well...

[Thunderbug]

Anotherthing

Yep I was right - It doesn't sound good.......