Spring 2023

Vital maintenance

Vital maintenance

In November, the UK’s Birmingham Airport carried out a programme of airfield maintenance work that saw large amounts of runway and taxiway resurfaced and improved, as well as supporting infrastructure repaired or enhanced

The work, which cost in the region of £2 million to execute, was done entirely at night, thus meaning that the airfield’s flight operations were not compromised in any way (the runway closed as scheduled only from 23:15hrs to 06:00hrs each night of the shutdown period). Carrying out this sort of work in November makes sense for the UK airport, given that the hours of darkness then are longer and so the hours of flying operations are fewer.
The project involved removing significant amounts of aircraft tyre rubber from taxiways and runways, as well as resurfacing. In fact, a team of approximately 80 engineers carried out the following improvements:

  • Replaced 500m2 of taxiway concrete located near the airport’s main terminal
  • Removed 16,600m2 of tyre rubber on the runway that had been deposited by landing aircraft
  • Cleared more than 6,000m of airfield drains to reduce the risk of flooding
  • Repaired 110m of cracked runway edge drain surface
  • Removed and replaced 1,100m2 of cracked runway surface
  • Repainted 10,000m of runway and taxiway line markings
  • Surveyed 180,000m2 of runway pavement using mobile vehicle systems to collect data on the surface and below-ground structures
  • Undertook safety-critical testing of airfield lighting and navigational aid systems

Once the day’s flight operations were concluded, specialist machinery was used to mill off 50mm of the existing surface of runway in need of repair before new asphalt was laid and compacted. The asphalt then set and the runway surface was ready to use again by the time flights were scheduled to resume a few hours later as dawn broke over the English West Midlands gateway.
A high-pressure water blasting system was also used to remove the rubber that had accumulated on surfaces from aircraft tyres. Removing this rubber is necessary to ensure that the runway surface retains a safe level of friction, and so grip, when wet.
Birmingham’s runway friction values are assessed using a type of continuous friction measuring equipment (CFME) called a Mu-Meter. The Mu-Muter is a small three-wheeled trailer equipped with a powerful on-board processor that compiles runway friction reports over a 100m rolling average.
The water blasting system is lorry-mounted and used an ultra-high-pressure water pump to deliver water to a rotary cleaning head mounted to the front of the vehicle. The rubber or paint is progressively removed from the surface as the jet head rotates and travels across the surface. Water and rubber is subsequently removed from the head under vacuum and collects in a debris tank.
On affected taxiways, cracked taxiway slabs measuring 5m by 5m are cut and broken out to a depth of up to 535mm. Steel reinforcement was added and different joints installed to prevent large cracks occurring in the new concrete. Fast-setting, pavement-quality concrete was used to replace the cracked slabs.
By the time the first flights pushed back a few hours later, the replaced sections were rock-solid and ready to bear the weight of an aircraft.
Nick Roberts, senior project manager at Birmingham Airport, comments: “Our airfield is vast, so the chances are most people, even those living nearby, won’t have been aware of our night-time activity this autumn.
“We do these vital jobs annually to ensure our runway and its taxiways are safe and in good shape to serve our customers for the next 12 months.”

Prior preparation and planning
The work was undertaken almost every night over the course of the month of November – Roberts confirms that the four-week programme of work encompassed a total of 20 shifts every Monday to Friday – but the project was much longer in the planning. Indeed, thinking about what will be needed a year from now starts pretty much now.
“We start to review the airfield works each January, so it takes around 10-12 months from planning and feasibility, through design and construction, to project handover,” Roberts explains.
First, the airport team needs to work out what resurfacing and other maintenance work will need to be carried out and then a package of work needs to be formalised. This project is then put out to tender. In the case of last November’s work, VolkerFitzpatrick acted as lead contractor, and did much of its work in-house or using airfield-experienced subcontractors.
“VolkerFitzpatrick has carried out major projects at the airport in recent years and was also the main contractor for our works carried during the November 2022 runway closure period,” Roberts confirms. Plus: “Our maintenance teams are supported by a number of specialist contractors who have previously worked at the airport.”
He continues: “During the works, we hold a pre-shift briefing with the contractors each night to discuss the plan and ensure appropriate controls are in place for all activities. Most of the airport team have been involved in these works many times before, so there’s a wealth of experience to draw upon for any challenges that may arise during the construction period.”
A similar process is likely to happen once again later this year, Roberts confirming: “We schedule planned maintenance around the airfield and this is normally carried out during November due to [the availability of] access to the runway.”