Heathrow's Northern Runway has tarmac replaced in overnight works

How to replace one of the world's busiest runways - while still using it

We are waiting for the last plane to leave Heathrow.

It is 10:45pm and we are in a convoy of road maintenance vehicles on the edge of the Northern Runway.

We see the plane take off. The call comes through on the radio and 130 vehicles head to the tarmac.

It reminds me of the cartoon Wacky Races, with all vehicles of different shapes and sizes speeding down the runway. The race is now on to replace it.

I have been given exclusive access to see the work. They have just five hours to do a section. Planes with passengers on board are already on their way from the US, Australia or the Far East to land here.

It is an incredible sight. There are 230 specialist workers who soon jump out of the vehicles, set up cones and measure lines. Then, within 10 minutes, the road millers start tearing up the surface.

The clock is ticking and the pressure is on.

The runway needs replacing as there is 10kg of plane tyre rubber embedded into the surface. The work is noisy. There is no pause between each type of work.

Heathrow's infrastructure delivery and strategic planning director is Alistair Awcock.

He is well aware of how important this job is.

"It's a scheme that we undertake about every sort of 10 - 12 years, based on the condition of the runway," said Awcock.

"Obviously, our runways are our most critical asset, it is the thing that keeps our business operating. So, we're willing to invest to make sure that this stays operational all year round.

"It is a big job. Every night our team come out over the whole of the summer, a three-month period, and resurface about 75 metres (246ft) of runway every night."

So how do they do it? Gawaine Yates is the delivery project manager.

"We've carefully planned this work. This team have practised this over and over again and fine-tuned it. This is a skill, they're specialist teams."

He said the old surface is taken off and recycled into making local roads or used in the construction industry.

"Once they've taken all of this material out, we will be ready to start preparing the surface for the new asphalt.

"Because we're creating a hole in Heathrow's most critical asset, we have to make sure that all of the asphalt is back."

The construction team needs the asphalt to be an exact thickness and type and to be ready exactly when they need it.

"We started mixing asphalt at 19:00 hours tonight. On site, we have two [mixers] back in plants at the south side of the airfield.

"Twenty-five wagons will bring the lower layer, and then once they've laid that, the wagons will all go right down to the southern end of the airfield again, and collect the next 500 tonnes worth of material to do our surface course material.

"Once that's all compacted and sealed, cooling will take place between the layers, and then once it's cool enough, we will apply the new paint markings."

This is one of the busiest runways in the world.

There are around 1,300 combined take-offs and landings a day at Heathrow. Most aircraft weigh around 200 tonnes, travelling about 140mph when touching down.

Gawaine Yates says the crews are well aware of the pressure.

They need to set up a construction site, do the work and be ready to leave at 04:30 so the operations team can carry out a foreign object debris inspection to ensure the runway is safe in time for 06:00 when the first plane lands.

"The logistics is very challenging. As far as laying asphalt, it's fairly standard, the sort of thing you see on the roads. It's just in a more concentrated scale. It's a much more difficult material to lay than the highways."

So what if they fall behind or there is a problem?

"Everybody knows what they're doing.
It's a very busy site, but they do this repetitively. We've practised it, we've run trials on it, and they've been learning on this to improve shift by shift."

"There's a lot to be done in a short window. If anything goes wrong, they feel that pressure.

"We have a heavy recovery truck on site every single night, in case one of these bits of equipment breaks down. That's a very rare occurrence, but we have to make sure that we can get that back off the runway."

By the end of the year, the project will have replaced around 200,000 tonnes of asphalt. Some construction jobs are deemed a success if no-one notices it. This is one of them.

Gawaine Yates says so far it has gone well.

"That's what we've been striving to do. We've not had a single late handback.

"The public have not known any dramas from here, because we're dealing with it on the night.

"We have resilience built into the shift, so that everybody knows what they're doing.

"If something goes wrong, we've done exercises to make sure that we can get back on track and deliver that handover by the absolute crystal latest... 05:30.

"We have to be, everybody done and dusted, ready to give it back to air traffic control, at 05:45, to vector that first aircraft into the runway at 06:00."

Any delay in the work would have serious consequences, Awcock said.

"Fingers crossed, we haven't had any operational issues.

"The implications of not handing back this runway to our operation is not just an impact to Heathrow but would impact the whole of the UK airspace."

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