Why new runways are not the solution

Only a new hub airport can balance our aviation needs with those of the environment.

A quarter of all those in Europe who are affected by aircraft noise live under the Heathrow flight-path. If there is a single statistic which underlines the failure of British aviation policy it is this. For decades, a combination of powerful lobbyists and weak decision-making has led ministers to slavishly accept the hodgepodge expansion of Heathrow. There has been very little vision, and very little evidence-based policy making.

The previous Labour government, for example, decided to build a third runway at Heathrow, and only then asked the independent Committee on Climate Change (CCC) to figure out how the UK could meet its 2050 carbon reduction target. They didn't allow the facts to affect their policy. But the CCC did some very useful work, and calculated that, based on increased plane loads, new technology and fuel improvements, our carbon budget allows for about a 60% increase on current passenger numbers, bringing us to around 368 million passengers per annum. This is still a very large increase in the proportion of our carbon emissions due to aviation – the industry would emit 37.5MtCO2 a year by 2050. It is harder to decarbonise aviation than other sectors. But this 60% increase represents a lot of opportunities for new destinations and new travellers - within our carbon cap.

So, how much new capacity do we need to build to take us up to this limit? The answer is none. We can reach that 60% increase with no third runway at Heathrow, no new Thames Estuary airport, no second runway at Gatwick or Stansted. And Department for Transport forecasts suggest that we won't get to that point until about 2030. In particular, Gatwick is already expanding into new markets with routes to China, South Korea and Vietnam. Stansted is only around 50% full, and it makes no sense whatsoever to build a second runway at either. Indeed, rather than pushing for new runways, both airports are campaigning for rail links and improved surface access to help their growth, which brings environmental gains too: up to half of emissions from aviation actually come from surface movements, rather than the planes.

It’s clear that Heathrow plays a very important role - it is our only hub airport, and caters for transfer passengers, particularly business users, and that enables flights to emerging markets to become economically viable. It’s also true that Heathrow is almost totally full. While in the short term there are a few tools available to encourage flights to transfer to Gatwick or Stansted, if we are to retain a successful hub airport and all the benefits it brings, we need to look at longer-term solutions. Mixed Mode operation and a large increase in night flights have been proposed, but they fail the same test as the third runway - they affect far too many people who already suffer massively from noise pollution. And it has a huge effect on London’s air quality. Heathrow is, simply put, in the wrong location for our current needs.

Boris Johnson, I suspect for electoral reasons, recognises that Heathrow is not the answer. But his solution is perhaps even more wrong. Located east of London in the Thames estuary, 'Boris Island' would be largely inaccessible for anyone living outside London and the south east, making it even harder to spread economic growth to the north and west of the country. It would essentially be a transfer hub for foreign travellers (paying no APD) and the City. Before construction could even begin, you'd have to somehow move or defuse the remains of the SS Richard Montgomery, a wartime liberty ship whose detonation would cause a small tidal wave up the Thames and possibly one of the world's largest non-nuclear blasts. The chance of bird-strike is also 12 times higher here, let alone the crippling effect it would have on this vital migratory route. The RSPB claimed it would be one of the worst environmental decisions the country has made. Finally, the expense of this project would be astronomical and it would take far too long to construct. You'd have to start the infrastructure from scratch. It's simply not a goer, and I am delighted that I and the Lib Dems rejected it so promptly.

Is there a better option? We have to be clear that total UK aircraft movements in 2050 cannot be above the limit suggested by the CCC. So there is no point in building capacity which would allow us to vastly exceed that limit. Our 2050 carbon reduction target is not some figure that can be fiddled if a future government realises they can't meet it. The effect on our children's economy and their environment would be immense. We must not burden them with an environmental debt from which they cannot escape. But that still leaves us with a 60% increase in passenger movements which is allowed within UK carbon budgets.

For now, we can meet it with the runways we have, using the capacity at Manchester and Birmingham, for example, but it makes sense to consider the option of having a new hub, bringing together runways in one place to link with all the transfer passengers and new routes they bring to bear. That new hub could only happen with the closure of other runways and airports to ensure a future government doesn't exceed the available carbon budget. And this new hub couldn't be just anywhere - it would have to be accessible to north and south of the country, and be somewhere which would pose minimal impact to the local population and to the local environment.

The Labour Party is at best vague on this - they "accept the Government’s decision to cancel the third runway at Heathrow" - but fail to say whether they actually support it or don't - and many of their backbenchers (and frontbenchers) still argue for the third runway. They also argue for more expansion of aviation in the south east, threatening to breach our environmental constraints.

Some Tories, such as the Transport Secretary, Justine Greening, understand the need for environmental considerations to play a key role in aviation policy, in keeping with the Coalition Agreement, but there is a growing band of pro-third runway MPs, including George Osborne. Few seem to take Boris Island that seriously.

This autumn, the Liberal Democrats will vote on a conference motion that presents a proper policy to the public, outside of the vested interests in the aviation industry. The public deserve an airport policy which balances the benefits from aviation with the harm it can do to the environment globally and locally. That is exactly what we’ll deliver.

A British Airways aircraft taxis past other parked aircraft at Terminal 5 of Heathrow Airport. Photograph: Getty Images.

Julian Huppert is the Liberal Democrat MP for Cambridge.

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Inside Big Ben: why the world’s most famous clock will soon lose its bong

Every now and then, even the most famous of clocks need a bit of care.

London is soon going to lose one of its most familiar sounds when the world-famous Big Ben falls silent for repairs. The “bonging” chimes that have marked the passing of time for Londoners since 1859 will fall silent for months beginning in 2017 as part of a three-year £29m conservation project.

Of course, “Big Ben” is the nickname of the Great Bell and the bell itself is not in bad shape – even though it does have a huge crack in it.

The bell weighs nearly 14 tonnes and it cracked in 1859 when it was first bonged with a hammer that was way too heavy.

The crack was never repaired. Instead the bell was rotated one eighth of a turn and a lighter (200kg) hammer was installed. The cracked bell has a characteristic sound which we have all grown to love.

Big Ben strikes. UK Parliament.

Instead, it is the Elizabeth Tower (1859) and the clock mechanism (1854), designed by Denison and Airy, that need attention.

Any building or machine needs regular maintenance – we paint our doors and windows when they need it and we repair or replace our cars quite routinely. It is convenient to choose a day when we’re out of the house to paint the doors, or when we don’t need the car to repair the brakes. But a clock just doesn’t stop – especially not a clock as iconic as the Great Clock at the Palace of Westminster.

Repairs to the tower are long overdue. There is corrosion damage to the cast iron roof and to the belfry structure which keeps the bells in place. There is water damage to the masonry and condensation problems will be addressed, too. There are plumbing and electrical works to be done for a lift to be installed in one of the ventilation shafts, toilet facilities and the fitting of low-energy lighting.

Marvel of engineering

The clock mechanism itself is remarkable. In its 162-year history it has only had one major breakdown. In 1976 the speed regulator for the chimes broke and the mechanism sped up to destruction. The resulting damage took months to repair.

The weights that drive the clock are, like the bells and hammers, unimaginably huge. The “drive train” that keeps the pendulum swinging and that turns the hands is driven by a weight of about 100kg. Two other weights that ring the bells are each over a tonne. If any of these weights falls out of control (as in the 1976 incident), they could do a lot of damage.

The pendulum suspension spring is especially critical because it holds up the huge pendulum bob which weighs 321kg. The swinging pendulum releases the “escapement” every two seconds which then turns the hands on the clock’s four faces. If you look very closely, you will see that the minute hand doesn’t move smoothly but it sits still most of the time, only moving on each tick by 1.5cm.

The pendulum swings back and forth 21,600 times a day. That’s nearly 8m times a year, bending the pendulum spring. Like any metal, it has the potential to suffer from fatigue. The pendulum needs to be lifted out of the clock so that the spring can be closely inspected.

The clock derives its remarkable accuracy in part from the temperature compensation which is built into the construction of the pendulum. This was yet another of John Harrison’s genius ideas (you probably know him from longitude fame). He came up with the solution of using metals of differing temperature expansion coefficient so that the pendulum doesn’t change in length as the temperature changes with the seasons.

In the Westminster clock, the pendulum shaft is made of concentric tubes of steel and zinc. A similar construction is described for the clock in Trinity College Cambridge and near perfect temperature compensation can be achieved. But zinc is a ductile metal and the tube deforms with time under the heavy load of the 321kg pendulum bob. This “creeping” will cause the temperature compensation to jam up and become less effective.

So stopping the clock will also be a good opportunity to dismantle the pendulum completely and to check that the zinc tube is sliding freely. This in itself is a few days' work.

What makes it tick

But the truly clever bit of this clock is the escapement. All clocks have one - it’s what makes the clock tick, quite literally. Denison developed his new gravity escapement especially for the Westminster clock. It decouples the driving force of the falling weight from the periodic force that maintains the motion of the pendulum. To this day, the best tower clocks in England use the gravity escapement leading to remarkable accuracy – better even than that of your quartz crystal wrist watch.

In Denison’s gravity escapement, the “tick” is the impact of the “legs” of the escapement colliding with hardened steel seats. Each collision causes microscopic damage which, accumulated over millions of collisions per year, causes wear and tear affecting the accuracy of the clock. It is impossible to inspect the escapement without stopping the clock. Part of the maintenance proposed during this stoppage is a thorough overhaul of the escapement and the other workings of the clock.

The Westminster clock is a remarkable icon for London and for England. For more than 150 years it has reminded us of each hour, tirelessly. That’s what I love about clocks – they seem to carry on without a fuss. But every now and then even the most famous of clocks need a bit of care. After this period of pampering, “Big Ben” ought to be set for another 100 or so years of trouble-free running.

The Conversation

Hugh Hunt is a Reader in Engineering Dynamics and Vibration at the University of Cambridge.

This article was originally published on The Conversation. Read the original article.