The Nightly Race to Resurface a Runway

The countdown starts at midnight. The 30-strong construction crew has six hours to resurface an aging 7,200-square-metre section of runway – and not a minute more.  

They’re working on 15R/33L, one of Toronto Pearson’s north-south landing strips. It’s been a decade since the last major resurfacing work on this runway, and the regular pounding from 70-tonne aircraft touching down at 250 km/h is beginning to show. The asphalt must be stripped away and replaced with a fresh surface. 

Over the course of two months, the crew will move section-by-section down the runway until its entire 2.7-kilometre length is resurfaced. Because of the direction of the airport’s prevailing winds, the north-south runways are used less frequently, so much of the work can be carried out in daylight. But at its far north end, 15R/33L crosses the airport’s longest east-west runway – the busiest in Canada. 

For the period between mid-April and mid-May when the construction crew is working in this area, it’s a different story. The east-west runway can only be shut for a few hours – and only during the dead of night. The pressure is on. 

“That busy runway has to be re-opened at exactly at 6 a.m. – numerous parts of the system depend on it,” says Andrew Payter, Manager of Aviation Programs and Coordination. Long before dawn, the airport’s terminals start filling with passengers and red-eye flights from the West Coast or Europe begin entering Toronto airspace. With traffic controllers already assigning planes to use the east-west runway, missing the deadline is not an option.  

But six hours is not much time to construct a surface that must be built to millimetre accuracy and endure for years to come. “It’s very tight,” says Simon Ho, Senior Project Manager of Capital Restoration. “Everything has to be planned to the minute.” 

Working flat out 

On these crucial nights, workers and machinery are pre-positioned to move in the moment controllers shut down the east-west runway. Over the previous few nights, they removed the embedded runway lighting on the north-south 15R/33L, milled away the old surface, and prepared the ground for the new one. The arrival of around a dozen trucks carrying hot asphalt kicks off the race against time – even the trucks themselves are fast-tracked through airside security as their cargo becomes unusable if it cools below 90C. 

The work crew starts by sending out three paving machines in a flying V formation. Each precisely deposits a layer of tough airport-grade asphalt that can be between 50 and 100 mm thick depending on how heavily used that part of the runway is. Next comes a fleet of compaction rollers with heavy steel drums that compress the asphalt. They are followed by vehicles with rubber rollers to smooth out the surface. And finally, another set of steel rollers, smaller this time, arrive to remove the rubber marks.  

The work has to be meticulous to meet exacting safety standards and carried out under time pressure.  With so little margin for error, every contingency is considered. The crew has spare machines on deck in case of a breakdown and mechanics are on standby to troubleshoot any technical problems.   

“There’s a lot of mitigation planning,” says Ho. “Because once you start the work you’re committed, you have to finish it that night.”   

After the new surface is laid, on subsequent nights the runway lights on 15R/33L will be replaced and markings repainted. Then, the whole show moves on to the next section of runway. And the next.  

Construction season 

The resurfacing of a runway is a big task, but it’s far from the only maintenance project planned for this summer. Between now and the end of October, Toronto Pearson’s annual airfield restoration program will see numerous other parts of the airfield receive some TLC. The list includes repaving several taxiways, replacing some concrete slabs on the apron, and rehabilitating the surfaces around the central de-icing facility.   

Years of design and planning work go into the program, which is carefully sequenced to minimize disruption during the July and August travel peak. The planning team consults with NAV CANADA and airlines, and they must even consider factors such as the airport’s capacity to bus passengers to planes if a gate needs to be temporarily closed.  

“There's a lot of coordination going on in the background,” says Payter.  

The work is part of a five-year rolling program of rehabilitation projects on the airfield. It is also an important step on the road to Pearson LIFT, the airport’s ambitious capital plan to invest in new facilities and upgrades.  

“It may not seem vital that we’re fixing up a runway that’s just used two percent of the time,” says Ho. “But that’s going to be incredibly important for our operational resiliency as we get into major construction in the future.”  

Photo credit: Simon Ho