[Tete_de_cuvee]

Once the Airbus A380’s teething problems are addressed, with its greater capacity of upto 853 passengers but realistically 525, and with engine noise being 50% quieter than a 747–400 on take-off, why doesn’t LHR allow these aircraft to operate in an extended time window?

Large quiet aircraft having access an hour earlier and an hour later to the current restrictions would aid in the short term.

[RogerVictor]

A380’s are an interesting one. Although they carry more passengers and therefore could consolidate on some routes the way the airport handles them is more important.

A B747 followed by another B747 needs 4 miles in trail for wake vortex separation. An A380 followed by a B747 needs 6 miles. 3 miles extra. That’s almost as much again. So, the idea that the A380 can release movements doesn’t work. It can very nearly cost an additional movement due to the extra space needed behind it. The situation is the same on departure. All aircraft following an A380 need an additional 1minute added to the norm.

A380’s aren’t the answer. A third runway is

[Tete_de_cuvee]

Great insight RogerVictor, much appreciated. Is vortex separation the same as the “jet wash” effect (Top Gun) ? Thanks

[RogerVictor]

I think jet wash is from the engines. Wake vortex is a result of the wings producing lift.

[RichHI1]

So my question is, which equipment produces the most effective runway use in terms of pax per minute? Is it still larger equipment or is there a sweet spot like 777,787 or 330?

[RogerVictor]

Ideally you want equipment all the same size. half going north and half going south. Technically at that point you could get 60 departures in 60 mins.

[RogerVictor]

You need equipment in the higher end of the ‘Heavy’ category. B77-300 and B747-400’s The A380 and the B747-800 are bumped up into the ‘Super’ category and that’s where you may end up losing time/distance for wake.

60 B777-300’s, equally split north and south

Perfect!

[RichHI1]

So A320,s and A380’s or 737 and 747 is not good option? If a new runway is built at LHR would it be more efficient if 1 was for Heavies and one for narrow bodies?

[MartynSinclair]

would you get better runway utilisation if both of the Heathrow runways were used for take of and landings at the same time leading to a more effective and efficient use of the runways and spacing?

[RogerVictor]

Yes – the only problem you’d have is integrating that onto the ground control. I quite like the idea of using Northolt as a ‘domestic airport’ and having a rail link between the two.

[MartynSinclair]

How difficult would it be to map out a ground movement flow?

At long last a supporter for Northolt!!!

[RichHI1]

I have often thought the same. The current administration has said people should use rail more. Whilst using Rail to California, Brazil or Japan is a non starter , building HS2 to Glasgow and Edinburgh could significantly reduce domestic air travel. Likely to be 10 – 15 years though as Birmingham is current focus and there are no longer any London to Birmingham flights (remember the Viscounts in the 1970’s?)

[RogerVictor]

I’m not a big fan of mixed mode. You have a few problems

1) The runways are too adjacent to do parallel approaches so they’d have to be staggered. You usually need a 6nm – 7nm gap in between inbounds to get a departure away. An A380 would need 10. There are problems at Heathrow with some of the runway entrances and the fact that it interferes with the ILS signal. The southern runway for instance, in bad weather, can’t have a Terminal 4 aircraft line up at the full length with anything within 15nm of touch down. Not good.

If you stagger aircraft 7nm apart on both runways you are effectively getting 3.5nm separation between them. On one runway we use 3nm separation. Where you do gain is in wake vortex. The runways are far enough apart that one landing on the northern and one on the southern can be 3nm diagonally apart and not affect each other. So an A380 could have a B737 3nm, diagonally, behind it on the other runway and not worry about vortex. Saves you 4nm if they were both on the same runway

2) If you are flying to Manchester, you fly north after departure. if you are flying to Paris, you fly south etc., KLM operate out of Terminal 4. they tend to turn north after departure. Lufthansa operate out of terminal 1 and, more or less, turn south after departure. The nearest runway for Lufthansa is 27R, the northern runway. For KLM it’s 27L, the southern runway. You can see the issue if they both get airborne at the same time. Add into that an aborted landing and you have a horrendous mess 2nm west of Heathrow.

Mixed mode can help alleviate congestion in times of disruption, for a short period. It can help reduce problems with vortex but it isn’t really a good way of operating full time. We already do a version of it when there are more aircraft wanting to land then take off.

There are many more issues with mixed mode and it’s a ‘chat over beer’ type thing rather than spouting off on here. The idea is good, the practicality is that it aviation has to have too high a margin of error for it to ever be *really* effective

Again, third runway is the answer. Just promise not to increase flights beyond a certain agreed formula

[Bucksnet]

Rich, the DVD set up common purpose.

RogerVictor, a third runway with no increase in flights would be great. 2 runways could be used for landings and it would eliminate stacking. Plus there would be no issues with increasing numbers of A380 flights and their wake vortex issues.

[transtraxman]

Bucksnet

That´s fine to get all the planes on the ground, but how do you get them off again? You would have to reverse the policy and have two runways for take offs and one for landings.

[Author]

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