BA cancellations due Dennis.
 

So, just why are BA cancelling short haul haul flights, tomorrow, including those of my family when the forecast shows winds , vis and cloud base WELL within limits of the current types of aircraft, and yes, I have just checked the LHR TAF.

Yes fog and low vis procedures I can understand but wind and rain, come on !!

...... and the GVA TAFMETAR til midnight tomorrow shows it wide open ! !

EGLL
From: 15/02/2020 00:01 UTC
To: 15/02/2020 23:59 UTCDUE TO STRONG WINDS AERODROME IS OPERATING UNDER DEMAND REDUCTION
PROCESS BETWEEN 1500 AND 2200 REFER TO THE AIP. PARTICIPATING
AIRLINE OPERATORS ARE REQUIRED TO REDUCE THEIR SCHEDULES BY 10
PERCENT.

So, why the reduction because of winds within X wind limits, I understand. Increased separation due cat 3s etc
Never seen anything like it in all my years of flying.

This is the TAF for Heathrow

TAF: EGLL 141703Z 1418/1524 21012KT 9999 -RA BKN012 TEMPO 1418/1508 6000RA BKN008 PROB30 TEMPO 1418/1419 21015G25KT PROB30 TEMPO 1422/1505 4000 DZ BKN004 TEMPO 1505/1508 20015G25KT BECMG 1508/1510 20019G30KT BECMG 1510/1512 BKN018 TEMPO 1512/1524 8000 RA PROB40 TEMPO 1512/1524 4000 +RA BKN012 BECMG 1514/1517 20028G42KT

The bold bit is likely the reason.

Shorthaul aircraft (320s...) crosswind landing limit is 38kts. That gives a crosswind component of 39kts. Out of limits for them. 747 has a wet crosswind limit of 25kts for landing I believe (?). That’s them out. If the forecast is correct then 100%, the wind will exceed limits at points during that forecast validity.

They wouldn’t cancel flights for the sake of it but to run a full programme with that forecast? Not a chance with how busy Heathrow is.

Mostly spacing on final due windspeed variations and more difficult to maintain an assigned speed / expected go-arounds and revectoring into a gap etc etc

With LHR being close to capacity it makes sense to pro-actively cancel flights, indeed the airport authorities encourage them to do so.

Greater spacing, greater numbers of go-arounds, extensive holding and possible diverts all conspire to make operating a full schedule very difficult.

Pro-actively cancelling flights, however understandably frustrating that can be, is the right thing to do. It gives everyone (including the airline) the chance to make alternative arrangements to try and get people to where they need/want to be.

As the NOTAM says, they are not encouraged to, they are required to do so. No idea what LHR have pegged their flow rate at for tomorrow but the issuing of the NOTAM clearly means it is below normal. Unfortunately for BA, being by far the biggest operator at LHR, a 10% reduction means quite a lot of cancelled flights.

Really? Were you paying attention?
Have you thought about the increased go around rate or difficulties with time based separation?

LHR uses time based separation, so ac spacing is physically closer.

Airspeed v ground speed.

In still wind, put aircraft 3 miles (or minimum vortex spacing) apart on the ILS at 160kts airspeed and you’ll land 40-42 per hour.

In a 60kts headwind ground speed drops to 100kts so landing rate falls to 30-34 per hour.

As others have said, Heathrow applies Time Based Separation to help reduce the distance between vortex pairs but there are still absolute minimum distances applied, 2.5 miles between non vortex pairs for example, so TBS helps reduce the wind effect but it’s not a panacea.

Now think about the way Heathrow is scheduled at 42 per hour, every hour. When the landing rate drops to 32 per hour in strong winds the ‘extra’ 10 per hour have to be taken out of the system. Cancelling long haul is not an option so short haul gets disproportionately affected.

I’d rather my flight was cancelled the day before so I could make better arrangements rather than travel to the airport and cross my fingers it operates.


(The figures above are not intended to be absolutely accurate but estimated to prove a point)

I recall reading that time-based separation recovers about half of the landings that would otherwise be lost in high winds in a distance-based separation scenario.

Thanks for the explanation of the LHR time based separation. That said, having operated a heavy across many parts of the world this is the first time in my long career I have seen this, due to winds, one lives and learns.

That said too, looking at the TAF with strong x winds forecast at prob. 40 % tempo, I would have expected to be able to land but would be carrying extra fuel to keep ALL options open.

...and yes, HARRIS, I WAS paying very close attention.

Retired..

As others have said it's not a handling/aircraft limitations issue

Just to add to all the previous comments "LHR" have demanded flow rate restrictions which are becoming more restrictive as the day goes through. Currently (AM) the allowed rate is already down to 38 an hour and by late PM it's down to 30.

It's been a feature of LHR ops for a long time now and whilst as DR UK has said Time Based Separation has helped it's not a complete solution. The BA shorthaul flying programme, being mainly LHR based, takes a major clobbering when these restrictions are put in place.

With the caveat that I don't have first hand experience of EGLL ops... I do know they are usually running at pretty well max capacity. Look back to last weekend and storm Ciara....regardless of increased spacing, how many aircraft went around off their first approach due windshear/turbulence? If 25% of inbounds made two approaches (or even more), then instead of (say) 40 arrivals per hour, you suddenly have demand of 50 per hour for the same number of aircraft. I can see how you'd very rapidly run out of capacity, then of course there are all the ones which may have had to divert elsewhere and eventually find their way back to base. I suspect that by proactively cancelling quite a few in advance, an airline can recover back to normal ops much quicker (rather than having to bus passengers around the UK / position empty aircraft back home etc) and presumably the overall disruption to the airline and its passengers will be lessened.

This holds true for any airport and any airline, obviously the quieter the operation, the more natural slack there is in the system.

At one stage 'Key Flights' were introduced . Master planning had identified which flts should be flown in disruptive times , thus enabling the operation to recover to normal in minimum time . Others could then be cancelled tactically or strategically . The Key flights were easily spotted on crew room a/c allocation , planning screens , etc .
Tactical canx , more costly , more disruptive .
Strategic canx , difficult commercial decision ; but once made less costly , less disruptive , and quicker to get back to a normal programme .

rgds condor .

With short haul, they also have the option to combine two rotations onto one, larger aircraft. I had that once when the southerly runway was closed for a landing incident. We were late but we all got to destination.

Its windy its going to cause disruption to their schedule, so they cancel ahead of the game in a way to minimize the cost to their business and reduce overall disruption.

No they don’t. The largest operators are required by Heathrow to reduce their flights. Read the NOTAMS!

:ok:
It appears Tom's post from late last night got missed/ignored..

​​​​​​Q) EGTT/QFALT/IV/NBO /A /000/999/5129N00028W
A) EGLL
B) 20/02/15 00:01 C) 20/02/15 23:59
E) DUE TO STRONG WINDS AERODROME IS OPERATING UNDER DEMAND REDUCTION PROCESS BETWEEN 1500 AND 2200 REFER TO THE AIP. PARTICIPATING AIRLINE OPERATORS ARE REQUIRED TO REDUCE THEIR SCHEDULES BY 10 PERCENT.

Also from Eurocontrol an update at 1815 UTC

Aerodromes:

EGLL (Heathrow)
Arrivals regulated due to weather - strong winds.
Moderate to high delays.

And they claim exceptional weather so no compensation.

Because windy days are exceptional, right?