All you wanted to know about Runway re-carpeting

If you’re planning to fly to Mumbai later this year, brace for even more congestion than you’re used to. Mumbai airport, the second busiest in the country, will close its main runway — Runway 27 — from November 1 this year until March 28 next year for major restoration and re-carpeting work.

Airport runways are built to exacting, internationally mandated standards. But frequent landing and take-off of flights lead to wear and tear of runways. Natural weather phenomena like rain and sun also affect the runway surface.

Therefore, depending on the volume of traffic and the variety of aircraft, the runway needs to be ‘re-carpeted’ every few years. How often this is done depends on how busy the airport is and the variety of aircraft that it handles.

Re-carpeting is essential for the safety of flights. All re-carpeting activities on runways are likely to lead to flights being rescheduled though they are not always cancelled or disrupted.

Airport runways at all times need to be of a specified strength or Load Classification Number (LCN), which is a system of classification of the supporting capacity of pavements without cracking or becoming permanently deformed. LCN varies from 60 for heavy aircraft like a Boeing 747 or Airbus A-380 to 15 for smaller Bombardier Q 400 aircraft.

The runway also needs to accommodate weight, length and safety margins for various varieties of aircraft. For example, an Airbus A-319 has a wing span of 34.1 meters and a wing area of 122.4 square meters while a Boeing 777-300 Extended Range aircraft has a wing span of 212.6 feet and a wing area of 4,605 square feet.

An airport like Mumbai which operates all these aircraft has to ensure that the runway is safe enough to ensure that the aircraft engines remain on the concrete area. Otherwise there is a risk of foreign objects getting sucked into the aircraft which could lead to an accident.

Re-carpeting is important as it ensures that the runway is in top condition to receive the aircraft. The process involves examining the runway for a variety of issues including whether the aircraft is having a smooth ride as it lands.

Load testing is usually done every four to five years to check the condition of the runway to see if there are undulations or if its weighing capacity is erratic in some places. If this is found to be so, emergency action is taken otherwise re-carpeting is done in the normal course. Very often when an aircraft lands on the runway some amount of rubber from the tyres can peel off which can be a risk. Sometimes water too accumulates or the runway surface breaks which leaves stones lying around that could get sucked into the aircraft engine and become a safety issue.

Re-carpeting of a runway normally sees operations at the airport being rescheduled. Normally airport operators set aside eight hours daily for re-carpeting work — one hour for preparing, six hours of work and another hour for currying. While this can delay flight schedules, it is important for the safety of operations.

The process could inconvenience flyers and push up ticket prices. But it is a small price to pay for flight safety.

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