Are 700 more planes a day expected to fly because of the Heathrow expansion?

Question

Some people are protesting a proposed expansion of London Heathrow. I saw some protestors of the Heathrow expansion with signs that read "Stop 700 more planes a day".

Greenpeace tells me "A third runway would mean 700 extra planes a day using Heathrow."

Are 700 more planes a day expected to fly because of the Heathrow expansion, as the signs imply?

I'm not sure that random protestors writing something on a sign makes it a notable claim. — RedSonja, May 02 '19 at 10:33
@RedSonja That doesn't mean you shouldn't ask the question... as OP is doing. — Cloud, May 02 '19 at 10:38
@Cloud It kinda does mean you shouldn't ask the question _on Skeptics SE_ though. The site tries to limit the questions to notable claims, so that it isn't just filled with "Someone told me that... is it true?" questions about anything that can come to someone's mind. https://skeptics.meta.stackexchange.com/questions/864/faq-must-all-questions-be-notable Now determining if this claim was notable or not is a different thing entirely. — JMac, May 02 '19 at 10:55
@J.D Much more so than just some signs held by protesters. I think it does a fine job showing the claim is notable now. You may have even been able to argue the first claim was notable anyways though, based on the article you had linked with it. Even harder to say it's not notable now though, which is a good step. — JMac, May 02 '19 at 13:56
If a sign by random protestors is notable then I will ask about "god hates fags". Well, no, but I could. — RedSonja, May 03 '19 at 06:52
Regarding the image: A journalist thought that the scene being depicted in the image was worth being noted - otherwise, it would not have been taken a picture of or published in an online article in the first place. It provides visual evidence of the claims being made by protesters as captioned in the article. — oldmud0, May 03 '19 at 16:29

score 58 · Answer 1 · edited Jun 17 '20 at 09:41

Heathrow Airport has a "dedicated website" for the planned creation of an additional runway. From the dedicated website (emphasis added):

Heathrow Today

98% capacity – Flight movements at Heathrow are capped at 480,000/year

473,000 flight movements a year (2016) – an average of 1,300 a day

Heathrow Expansion:

740,000 flight movements capacity

Assuming the capacity in the expanded airport is still per year (as is explicitly stated on another Heathrow Airport website), there would be the capacity for an additional 260,000 flights per year. That is equivalent to ~712 flights per day offered by the additional capacity.

OAG, "an air travel intelligence company," predicts a total of 140,556 air traffic movements (ATMs). Their report is pretty comprehensive and includes long-haul, short-haul, etc. A single departure (and arrival) counts as one ATM. Thus, the increase of 140,556 ATMs is equivalent to 385 additional flights per day. Equivalently, 54.1% of the additional capacity is expected to be used, and not 100%.

To summarize:

Are 700 more planes a day expected to fly because of the Heathrow expansion, as the signs imply?

Maybe. In the short term, probably not. In the long term, probably yes. The expansion will increase the airport capacity by 712 flights per day. This is not a guarantee that 712 extra flights will occur a day. In fact, an airline analysis company predicts just 385 additional flights per day two years after the expansion. This figure is nowhere near 700.

To put the numbers into context, 2016 saw an average of ~1296 flights a day.

Assuming that (1) the 2016 number is accurate 2 years after the expansion and (2) the prediction (385 flights/day) mentioned above is accurate, two years after the expansion 22.9% of all flights will be from this new runway. The percent increase in flights will be 29.7%.

Assuming that in an unspecified number of years, (1) the 2016 number is still accurate for the first two runways and (2) there will be an additional 700 flights a day from the third runway, 35.1% of all flights will be from the new runway. The percent increase in flights will be 54.0%.

Additional comments for the interested reader:

The OAG report cited earlier specifically states (emphasis added):

In our cautious assessment of the opportunities, we project that over half of the new capacity could be used within two years from opening, if not faster allowing for existing carrier expansion.

What this means is that the projections are for two years after the expansion opens. Of course, the long-term environmental impacts of any airport expansion (which is probably what the protesters pictured in the question are interested in) last much longer than two years. Over the long term, it is indeed possible that the airport will be back at a full (or close to full) capacity. When the airport is at 98.3% capacity, there will be an increase of 700 flights, relative to now.

In 2014, the London Mayor's office wrote, in response to a study by York Aviation and Oxford Economics (emphasis added):

The analysis highlights how a third runway at Heathrow would fail to reverse the decline in regional connectivity and predicts that even with a third runway the number of domestic routes would be reduced by the loss of the existing Leeds/Bradford route. A third runway would fill up very quickly due to suppressed demand at Heathrow, which already runs at 99 per cent of its capacity. Pressure on airlines to use slots for the most profitable routes would then mean domestic services would be crowded out again, which would prohibit new routes being set up and mean that established services to cities like Manchester, Edinburgh, Glasgow and Newcastle would not be immune to a further loss of frequency.

More recently, a Wired article article published 9 June 2018 wrote:

But Warnock-Smith¹ warns that Heathrow will eventually fill up again unless air travel is redistributed to make use of spare capacity at other UK airports. “Otherwise in 25 years, we will be having the same debates about a fourth runway at Heathrow,” he adds.

And from a Gov.UK blog about the filling of other London airports by 2030:

However, our airports are filling up. Heathrow has been running at full capacity for years. Evidence shows that the other London airports will be full by 2030. The need for increased capacity is ever-growing, and a policy was needed, especially in light of the UK’s decision to leave the European Union.

The Gov.UK post supports the previously cited two articles, as without excess capacity in London's other airports, they will have to turn to the now expanded and partly empty London Heathrow. The fact that London's airports are filling up and are predicted to be full by 2030 is also corroborated here (UK Department of Transport), here (London Assembly Transport Committee), and here (Greater London Authority).

Thus, there isn't doubt that, in the long term, the third runway can and will fill up. In this sense (that the runway expansion will "create" 700 more flights a day), the protesters are right to worry and their sign is accurate.

¹Associate head of the School for Aviation and Security at Buckinghamshire New University

The report you linked seems to be projecting around 10 years into the future. So what it's actually saying is "10 years from now, we expect around 385 additional flights per day". The report also notes that "This clearly leaves plenty of space for existing carrier development and expansion", suggesting that there will be yet more flights beyond the timeframe of their projection. The protesters' signs didn't specify a timeframe but if, 15 years from now, 700 flights are taking off per day, then both the report and the protestors will be correct. — ymbirtt, May 02 '19 at 07:56
Having read a bit more, "In our cautious assessment of the opportunities, we project that over half of the new capacity could be used within two years from opening, if not faster". I think it's reasonable to think that the protesters are worried about a timeframe somewhat longer than 2 years beyond the construction time. — ymbirtt, May 02 '19 at 07:58
@ymbirtt Thank you for your detailed and well thought out comments. What do you think about the edit? — Barry Harrison, May 02 '19 at 08:10
I generally agree with it. Of course, my preconceived position going into this was "Heathrow is going to use up every last inch of capacity they can", so of course I'm going to be happy that this now reflects that, but I like the sources you've cited. — ymbirtt, May 02 '19 at 12:10
Depending which way the Brexit chips fall, the future state can look different as well. — Stian, May 02 '19 at 12:26
@StianYttervik Your comments are insightful, could I ask what effects you specifically predict? (I'm curious.) Would it be reduced commerce and flights? — Barry Harrison, May 02 '19 at 13:35
Another point is that not all of these new flights to Heathrow mean new plants in the sky; some of them could just be flights that are landing at Heathrow instead of another London airport. — Gavin S. Yancey, May 02 '19 at 14:35
Going by your capacity numbers, there is an average of 1289 flights a day already. It may be worth stating as much, to put the numbers into context. - the 2 year increase is +~25% and full capacity would be +~50% — Baldrickk, May 02 '19 at 14:58
@g.rocket Yes, that is valid. Current studies are predicting that those other airports will be full by 2030. Any expansion at London Heathrow will change those predictions, though. — Barry Harrison, May 02 '19 at 17:48
Accurate signs? Then we need to know whether 700 more flights a day will "wreck the UK climate target". — Mazura, May 02 '19 at 21:21
@Mazura Fair point, and bad wording on my part. My apologies. I feel like your followup is beyond the scope of the question. However, I don't like seeing "beyond the scope of..." as an answer. So, I'll edit the answer to more accurately reflect the conclusion, look into this interesting topic, and edit the answer again to incorporate any new info. — Barry Harrison, May 02 '19 at 21:29
That's what the signs say and that's what the OP should've asked. What airport in a major city *doesn't* operate at capacity? — Mazura, May 02 '19 at 21:35
@Mazura I wouldn't feel comfortable changing the meaning of the OP's question...Would you? — Barry Harrison, May 02 '19 at 21:55
Yes, that's what SE is all about: molding a question into that which can be answered. If it cannot be, it should be frame challenged. — Mazura, May 02 '19 at 22:39
@Mazura If you would like to edit, you can do so. I wouldn't. — Barry Harrison, May 02 '19 at 23:51
Oh I misread, you *don't* like frame challenges; that's the part I thought you were going to add. But you got rid of the part about the signs, +1. — Mazura, May 03 '19 at 01:42
@Mazura No worries, now I think we both misread... Yes, I was going to add to the answer. I haven't found convincing sources yet though, so I am still looking. What i meant is: Whether or not the OP's question is good, I'm not going to go out of my way to edit somebody else's question. That's all I meant. — Barry Harrison, May 03 '19 at 05:09

score 8 · Answer 2 · answered May 01 '19 at 23:50

8

Yes, assuming that the airport continues to run at 98% capacity or higher.

According to Heathrowexpansion.com (a site apparently also owned by the airport), the expansion would have a "740,000 flight movements capacity" (per year for three runways) while currently the capacity is 480,000/year. This makes the math to figure out the new cap (740,000-480,000)/365 which is about 712 flights per day more than the previous cap. If they run at 98% capacity that makes it 698 flights per day extra.

answered May 01 '19 at 23:50

Laurel

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But that's a big assumption to make when you've increased capacity by 50%. – Bob May 02 '19 at 02:25
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@Bob: Unused capacity is a bad thing, from a capitalist standpoint. If they don't intend to ever *use* that capacity, the expansion would be oversized. Economics wise, you want to run as close to 100% capacity as possible... – DevSolar May 02 '19 at 07:24
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@DevSolar: You can’t add half a runway. Economics wise, you want more capacity, and enough to minimise the chances that you need another extension some years later. – gnasher729 May 02 '19 at 09:58
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@gnasher729 When you can't add half a runway, you either add none and increase the airport fee to reduce the demand so you don't need it, or you add one and reduce the fee accordingly. – Dmitry Grigoryev May 02 '19 at 10:57
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@DmitryGrigoryev Increasing the airport fee may not be possible for all airports, for example, in the UK, airport prices at LGW, LHR, and STN are subject to price caps. – Andrew Morton May 02 '19 at 13:38
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@DevSolar That simply isn't true. Only fools would redesign a system to continue to work at 98% capacity. Any textbook on queuing theory will demonstrate that once you exceed about 80%, bad things start to happen. Capitalists want to maximise the profit a system generates, which is *not* the same as minimizing its cost to the exclusion of everything else. – alephzero May 02 '19 at 14:02
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@alephzero: You'd be amazed at what people are willing to do to maximize short-term profits. ;-) But OK, 80% then ("...as close to 100% *as possible*..."). Until they exceed that and start planning the next expansion. ;-) – DevSolar May 02 '19 at 14:08
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@alephzero You're thinking as an engineer/programmer/mathematician, not as an faceless corporation ruled by the needs of the bottom line. Stupid decisions from a practical viewpoint happen all the time 'cause someone wanted to maximize profits using the shorter, easier path instead of the correct one. Investors wouldn't like unused capacity, for example, and it would be a hard sell for them. – T. Sar May 02 '19 at 19:48
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@Bob, in the case of London Heathrow, it's not a big assumption. It's a small one. It's been operating at capacity for years now, and there's plenty of pent-up demand. – Mark May 02 '19 at 20:28
@gnasher729 yes you can, you can add a short runway that is only fit for 20% of your traffic, at that point you'd have 2-1/2 runways. – Harper - Reinstate Monica May 02 '19 at 22:41
@Harper: You can, but does it scale? *If* the hassle of adding a short runway is (wild guess) 70% of adding a normal runway, it wouldn't make sense to do this for 20% of traffic - for that guess, I'm assuming that the paperwork will be comparable for building any sort of commercial runway at all. – Piskvor left the building May 03 '19 at 07:02
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Heathrow actually does use 98% of its capacity, though. If you read a textbook on queueing theory and conclude that terrible things are happening over the skies of Heathrow, then you misapplied the theory. Sure, planes can't be sure of their landing slot when they depart for Heathrow, and have to wait to land, and sometimes get diverted, and sometimes planes sit on the tarmac. None of which is especially ideal, but the the people involved (including passengers) don't want to pay 25% extra to have only 80% utilization to reduce those uncertainties. If you don't like it fly to Southend instead. – Steve Jessop May 03 '19 at 09:01
@DevSolar 'the expansion would be oversized. ' That's only true when an expansion is multi-unit; however building half a runaway is not really feasable... – May 03 '19 at 12:29
@Piskvor The limitIng factor in such a densely populated place as LHR is land acquisition. – Harper - Reinstate Monica May 03 '19 at 14:01
@alephzero any reasonable expansion will (in a reasonably short time, a few years at most) make it work (almost) at capacity. The reason is that everyone involved stands to make money from actually filling slots. Given that Heathrow is so well-trafficked, many airlines that don't fly there will want to chip in get piece of the action. That means many new routes, e.g. West-Europe-regional to international, open up. Notice how [all top 50 airports grew in 2018](https://en.wikipedia.org/wiki/List_of_busiest_airports_by_passenger_traffic#Preliminary_2018_statistics). – JJJ May 04 '19 at 16:29

Are 700 more planes a day expected to fly because of the Heathrow expansion?

2 Answers2