LHR mixed mode trial
 

The trial period for using LHR's 2 runways in mixed mode is ending soon, with the next period covering the Olympics. My observation is that it has very rarely been used during the trial period. Does anyone in the ATC world want to comment on whether useful experience of mixed mode has been gained? Thanks.

Perhaps a call to Gatwick might help?;)

SGC

The current trial, called operational freedoms, is not mixed mode.

The current trial involves interleaved landings and takeoffs on the same runway, which is the generally accepted definition of mixed mode, albeit in this case only involving one runway at a time (while the other operates in segregated mode) and only for limited periods.

What the trial isn't is parallel mixed mode (sometimes confusingly abbreviated to simply mixed mode), which is the term used to describe simultaneous use of mixed mode on two or more parallel runways or, in ICAO-speak, "mixed parallel operations".

Ok, so using your definition we've always been doing mixed mode.

I was trying to make the point that the trial is not for the commonly held definition of mixed mode. It merely changed some of the time-based triggers which allow us to use the promulgated departure runway for arrivals, using our current procedures.

Okaaaaaayyy.
Let's try that one again.
Can any LHR ATCer say how the trial that is just ending has gone?

A quick flick through the published results up to mid-Feb at www.heathrowtrial.com would suggest around 3,500 landings on the departure runway since the start of the trial, of which 1500 or so were during the 0600-0700 period and so fall outside the scope of the trial provisions.

The trial also includes departures from the arrivals runway, of which there appear to have been around 50.

Excellent data there - many thanks. Interesting that noise complaints are higher, despite the relatively low number of affecting flights.

First such trials - then known as parallel landing trials were in the 60s (I wrote a magazine article about the procedures). It was a no-go because of the unequal offering of traffic from north and south and the dreadful ground control problems. Staffing requirements were very high too so how they would do it now with much less staff I don't know! Maybe all the problems have been resolved.... but I'd still like a grandstand seat of GMC when it happens.

You'd need to get up early :O

Here's what you'd have seen before breakfast today:

AA100 06:03 27R
BA112 06:05 27L
VS004 06:06 27R
BA124 06:07 27L
BA078 06:08 27R
BA206 06:09 27L
SA234 06:11 27R
BA216 06:12 27L
CX255 06:14 27R
VS602 06:15 27L
BA106 06:16 27R
BA058 06:17 27L
AA174 06:19 27R
GF007 06:20 27L
VS012 06:21 27R
CO110 06:23 27L
BA072 06:24 27R
BA174 06:25 27L
DL270 06:27 27R
DL003 06:29 27L
VS022 06:30 27R

Not to mention half a dozen departures squeezed in between those arrivals. Sheer poetry.

/pedant mode on

DaveReid, the figure of 3500 you quote, is that all aircraft that landed on the departure runway on westerlies after 0700? If so, then lots, if not the majority, of them would have come under the usual TEAM criteria, so are not part of the Ops Freedoms trial.

Also, the practice you describe of landing on both runways before 0700 is not part of the trial. We've always done that, I'm sure HD can remember it!

Sorry to be a pedant, but there is a great deal of misinformation about Operational Freedoms and what is happening at LHR.

/pedant mode off

No argument there - in fact I said as much in my original post:

<<Here's what you'd have seen before breakfast today:>>

Did it for most of my life, Dave!

Sorry, Gonzo, I've just realised I didn't answer the first part of your question.

As far as I can deduce from the published stats, the 3500 figure is the total number of landings which were either out-of-alternation (on westerlies) or on 09R (on easterlies). That includes the 1500 "traditional" 0600-0700 TEAM landings which would have happened even without the trial.

I'm pretty sure that everything that landed on the departure runway after 0700 is accounted for in the balance of 2000.

Post-0700 landings are identified in the stats as TEAM (on easterlies) or TEAM* (on westerlies), with the asterisk indicating that those were a use of Operational Freedoms.

What I don't fully understand is why OFs appear not to be applied when on easterlies. It seems a bit odd that a 10-minute delay is enough to trigger their use on westerlies, but on easterlies ATC presumably have to sit on their hands until the delay has built up to 20 minutes before deploying TEAM under the pre-trial criteria.

Those figures look like 84 movements per hour.

What's the max. you can shift?

On the beach

Hourly record 100, daily record 1386, achived on July 18 2011.

At least that's what I was told when I was there :)

It will be interesting to get the commentary in the report as to what periods in the four months were subject to the 20 minute delay that can trigger normal TEAM and what periods were subject to the 10 minute delay to trigger trial TEAM*.

Of course the delay periods include delays at the originating airport (as well as en-route delays and stack-holding delays) and the trial can be triggered merely by anticipating that the delay time will be reached unless the freedom measures are implemented !

Goodness knows how ATC manage to keep track of this - perhaps someone continually tracks these times and hoists a flag / blows a whistle when the trial can start and lowers it for the "all clear".

DaveReid, on easterlies we can land on either runway, regardless of delay.

OK, now I'm completely confused.

Do you mean during the trial, or before it, or both ?

I ask because, according to the DfT:

"When severe inbound congestion occurs, or is expected to occur, involving airborne holding delays of 30 minutes or more, with at least 20 minutes delay in the inner stacks, it is NATS' practice to land additional aircraft on the assigned departure runway if it considers the landing rate can be increased (e.g. local weather conditions permitting). The procedure is known as Tactically Enhanced Arrival Measures (TEAM)."

which would suggest that delay has always been a criterion, with no distinction made between easterlies and westerlies.

If, on the other hand, there aren't actually any triggers that apply on easterlies, then landing on 09R isn't a tactical measure, it's just SOP - but then why are 09R landings being identified as TEAM in the stats ?

Answers on a postcard, please.

Operations on parallel runways are dependent or independent in either mixed or segregated mode. This is covered by the SOIR rules ICAO Doc 9643.

Heathrow was built before these rules were developed and the two runways are so far apart that under SOIR they can be counted as independent in all modes of operation.

Therefore, leaving the Cranford Agreement to one side, ATC could treat each runway as if it was a separate airport. Clearly issues about landing runway and final terminal destination revolve around which hold arrivals are picked from and hence how to control traffic on the northern runway heading for T4 and vice versa.

Nevertheless. If Gatwick single runway ops can deliver over 50 per hour on one runway that kinda points at 100/hr at LHR. Or am I missing something?

SGC